Merge remote-tracking branch 'scrapy/master' into dupefilter-redirects

.bandit.yml

@@ -1,5 +1,6 @@
 skips:
 - B101
+- B113  # https://github.com/PyCQA/bandit/issues/1010
 - B105
 - B301
 - B303
@@ -8,6 +9,7 @@ skips:
 - B311
 - B320
 - B321
+- B324
 - B402  # https://github.com/scrapy/scrapy/issues/4180
 - B403
 - B404
@@ -16,3 +18,4 @@ skips:
 - B503
 - B603
 - B605
+exclude_dirs: ['tests']

.bumpversion.cfg

@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 2.3.0
+current_version = 2.11.0
 commit = True
 tag = True
 tag_name = {new_version}

.coveragerc

@@ -3,3 +3,4 @@ branch = true
 include = scrapy/*
 omit =
   tests/*
+disable_warnings = include-ignored

.flake8

@@ -0,0 +1,22 @@
+[flake8]
+
+max-line-length = 119
+ignore = W503, E203
+
+exclude =
+    docs/conf.py
+
+per-file-ignores =
+# Exclude files that are meant to provide top-level imports
+# E402: Module level import not at top of file
+# F401: Module imported but unused
+    scrapy/__init__.py:E402
+    scrapy/core/downloader/handlers/http.py:F401
+    scrapy/http/__init__.py:F401
+    scrapy/linkextractors/__init__.py:E402,F401
+    scrapy/selector/__init__.py:F401
+    scrapy/spiders/__init__.py:E402,F401
+
+    # Issues pending a review:
+    scrapy/utils/url.py:F403,F405
+    tests/test_loader.py:E741

.git-blame-ignore-revs

@@ -0,0 +1,7 @@
+# .git-blame-ignore-revs
+# adding black formatter to all the code
+e211ec0aa26ecae0da8ae55d064ea60e1efe4d0d
+# re applying black to the code with default line length
+303f0a70fcf8067adf0a909c2096a5009162383a
+# reaplying black again and removing line length on pre-commit black config
+c5cdd0d30ceb68ccba04af0e71d1b8e6678e2962

.github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,13 @@
+---
+name: Question / Help
+about: Ask a question about Scrapy or ask for help with your Scrapy code.
+---
+
+Thanks for taking an interest in Scrapy!
+
+The Scrapy GitHub issue tracker is not meant for questions or help. Please ask
+for help in the [Scrapy community resources](https://scrapy.org/community/)
+instead.
+
+The GitHub issue tracker's purpose is to deal with bug reports and feature
+requests for the project itself.

.github/workflows/checks.yml

@@ -0,0 +1,46 @@
+name: Checks
+on: [push, pull_request]
+
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  checks:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: "3.12"
+          env:
+            TOXENV: pylint
+        - python-version: 3.8
+          env:
+            TOXENV: typing
+        - python-version: "3.11"  # Keep in sync with .readthedocs.yml
+          env:
+            TOXENV: docs
+        - python-version: "3.12"
+          env:
+            TOXENV: twinecheck
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Run check
+      env: ${{ matrix.env }}
+      run: |
+        pip install -U tox
+        tox
+
+  pre-commit:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: pre-commit/action@v3.0.0

.github/workflows/publish.yml

@@ -0,0 +1,25 @@
+name: Publish
+on:
+  push:
+    tags:
+      - '[0-9]+.[0-9]+.[0-9]+'
+
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.12
+      - run: | 
+          pip install --upgrade build twine
+          python -m build
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@v1.6.4
+        with:
+          password: ${{ secrets.PYPI_TOKEN }}

.github/workflows/tests-macos.yml

@@ -0,0 +1,30 @@
+name: macOS
+on: [push, pull_request]
+
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  tests:
+    runs-on: macos-11
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Run tests
+      run: |
+        pip install -U tox
+        tox -e py
+
+    - name: Upload coverage report
+      run: bash <(curl -s https://codecov.io/bash)

.github/workflows/tests-ubuntu.yml

@@ -0,0 +1,82 @@
+name: Ubuntu
+on: [push, pull_request]
+
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: 3.9
+          env:
+            TOXENV: py
+        - python-version: "3.10"
+          env:
+            TOXENV: py
+        - python-version: "3.11"
+          env:
+            TOXENV: py
+        - python-version: "3.12"
+          env:
+            TOXENV: py
+        - python-version: "3.12"
+          env:
+            TOXENV: asyncio
+        - python-version: pypy3.9
+          env:
+            TOXENV: pypy3
+        - python-version: pypy3.10
+          env:
+            TOXENV: pypy3
+
+        # pinned deps
+        - python-version: 3.8.17
+          env:
+            TOXENV: pinned
+        - python-version: 3.8.17
+          env:
+            TOXENV: asyncio-pinned
+        - python-version: pypy3.8
+          env:
+            TOXENV: pypy3-pinned
+        - python-version: 3.8.17
+          env:
+            TOXENV: extra-deps-pinned
+        - python-version: 3.8.17
+          env:
+            TOXENV: botocore-pinned
+
+        - python-version: "3.12"
+          env:
+            TOXENV: extra-deps
+        - python-version: "3.12"
+          env:
+            TOXENV: botocore
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install system libraries
+      if: contains(matrix.python-version, 'pypy') || contains(matrix.env.TOXENV, 'pinned')
+      run: |
+        sudo apt-get update
+        sudo apt-get install libxml2-dev libxslt-dev
+
+    - name: Run tests
+      env: ${{ matrix.env }}
+      run: |
+        pip install -U tox
+        tox
+
+    - name: Upload coverage report
+      run: bash <(curl -s https://codecov.io/bash)

.github/workflows/tests-windows.yml

@@ -0,0 +1,46 @@
+name: Windows
+on: [push, pull_request]
+
+concurrency:
+  group: ${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  tests:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: 3.8
+          env:
+            TOXENV: windows-pinned
+        - python-version: 3.9
+          env:
+            TOXENV: py
+        - python-version: "3.10"
+          env:
+            TOXENV: py
+        - python-version: "3.11"
+          env:
+            TOXENV: py
+        - python-version: "3.12"
+          env:
+            TOXENV: py
+        - python-version: "3.12"
+          env:
+            TOXENV: asyncio
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Run tests
+      env: ${{ matrix.env }}
+      run: |
+        pip install -U tox
+        tox

.gitignore

@@ -14,6 +14,8 @@ htmlcov/
 .coverage
 .pytest_cache/
 .coverage.*
+coverage.*
+test-output.*
 .cache/
 .mypy_cache/
 /tests/keys/localhost.crt
@@ -21,3 +23,6 @@ htmlcov/
 
 # Windows
 Thumbs.db
+
+# OSX miscellaneous
+.DS_Store

.isort.cfg

@@ -0,0 +1,2 @@
+[settings]
+profile = black

.pre-commit-config.yaml

@@ -0,0 +1,24 @@
+repos:
+- repo: https://github.com/PyCQA/bandit
+  rev: 1.7.5
+  hooks:
+  - id: bandit
+    args: [-r, -c, .bandit.yml]
+- repo: https://github.com/PyCQA/flake8
+  rev: 6.1.0
+  hooks:
+  - id: flake8
+- repo: https://github.com/psf/black.git
+  rev: 23.9.1
+  hooks:
+  - id: black
+- repo: https://github.com/pycqa/isort
+  rev: 5.12.0
+  hooks:
+  - id: isort
+- repo: https://github.com/adamchainz/blacken-docs
+  rev: 1.16.0
+  hooks:
+  - id: blacken-docs
+    additional_dependencies:
+    - black==23.9.1

.readthedocs.yml

@@ -3,10 +3,15 @@ formats: all
 sphinx:
   configuration: docs/conf.py
   fail_on_warning: true
+
+build:
+  os: ubuntu-20.04
+  tools:
+    # For available versions, see:
+    # https://docs.readthedocs.io/en/stable/config-file/v2.html#build-tools-python
+    python: "3.11"  # Keep in sync with .github/workflows/checks.yml
+
 python:
-  # For available versions, see:
-  # https://docs.readthedocs.io/en/stable/config-file/v2.html#build-image
-  version: 3.7  # Keep in sync with .travis.yml
   install:
     - requirements: docs/requirements.txt
     - path: .

.travis.yml

@@ -1,75 +0,0 @@
-language: python
-dist: xenial
-branches:
-  only:
-    - master
-    - /^\d\.\d+$/
-    - /^\d\.\d+\.\d+(rc\d+|\.dev\d+)?$/
-matrix:
-  include:
-    - env: TOXENV=security
-      python: 3.8
-    - env: TOXENV=flake8
-      python: 3.8
-    - env: TOXENV=pylint
-      python: 3.8
-    - env: TOXENV=docs
-      python: 3.7  # Keep in sync with .readthedocs.yml
-    - env: TOXENV=typing
-      python: 3.8
-
-    - env: TOXENV=pinned
-      python: 3.6.1
-    - env: TOXENV=asyncio-pinned
-      python: 3.6.1
-    - env: TOXENV=pypy3-pinned PYPY_VERSION=3.6-v7.2.0
-
-    - env: TOXENV=py
-      python: 3.6
-    - env: TOXENV=pypy3 PYPY_VERSION=3.6-v7.3.1
-
-    - env: TOXENV=py
-      python: 3.7
-
-    - env: TOXENV=py PYPI_RELEASE_JOB=true
-      python: 3.8
-      dist: bionic
-    - env: TOXENV=extra-deps
-      python: 3.8
-      dist: bionic
-    - env: TOXENV=asyncio
-      python: 3.8
-      dist: bionic
-install:
-  - |
-      if [[ ! -z "$PYPY_VERSION" ]]; then
-        export PYPY_VERSION="pypy$PYPY_VERSION-linux64"
-        wget "https://downloads.python.org/pypy/${PYPY_VERSION}.tar.bz2"
-        tar -jxf ${PYPY_VERSION}.tar.bz2
-        virtualenv --python="$PYPY_VERSION/bin/pypy3" "$HOME/virtualenvs/$PYPY_VERSION"
-        source "$HOME/virtualenvs/$PYPY_VERSION/bin/activate"
-      fi
-  - pip install -U tox twine wheel codecov
-
-script: tox
-after_success:
-  - codecov
-notifications:
-  irc:
-    use_notice: true
-    skip_join: true
-    channels:
-    - irc.freenode.org#scrapy
-cache:
-  directories:
-    - $HOME/.cache/pip
-deploy:
-  provider: pypi
-  distributions: "sdist bdist_wheel"
-  user: scrapy
-  password:
-    secure: JaAKcy1AXWXDK3LXdjOtKyaVPCSFoCGCnW15g4f65E/8Fsi9ZzDfmBa4Equs3IQb/vs/if2SVrzJSr7arN7r9Z38Iv1mUXHkFAyA3Ym8mThfABBzzcUWEQhIHrCX0Tdlx9wQkkhs+PZhorlmRS4gg5s6DzPaeA2g8SCgmlRmFfA=
-  on:
-    tags: true
-    repo: scrapy/scrapy
-    condition: "$PYPI_RELEASE_JOB == true && $TRAVIS_TAG =~ ^[0-9]+[.][0-9]+[.][0-9]+(rc[0-9]+|[.]dev[0-9]+)?$"

AUTHORS

@@ -1,8 +1,8 @@
 Scrapy was brought to life by Shane Evans while hacking a scraping framework
 prototype for Mydeco (mydeco.com). It soon became maintained, extended and
 improved by Insophia (insophia.com), with the initial sponsorship of Mydeco to
-bootstrap the project. In mid-2011, Scrapinghub became the new official
-maintainer.
+bootstrap the project. In mid-2011, Scrapinghub (now Zyte) became the new
+official maintainer.
 
 Here is the list of the primary authors & contributors:
 

CODE_OF_CONDUCT.md

@@ -1,74 +1,133 @@
+
 # Contributor Covenant Code of Conduct
 
 ## Our Pledge
 
-In the interest of fostering an open and welcoming environment, we as
-contributors and maintainers pledge to make participation in our project and
-our community a harassment-free experience for everyone, regardless of age, body
-size, disability, ethnicity, gender identity and expression, level of experience,
-nationality, personal appearance, race, religion, or sexual identity and
-orientation.
+We as members, contributors, and leaders pledge to make participation in our
+community a harassment-free experience for everyone, regardless of age, body
+size, visible or invisible disability, ethnicity, sex characteristics, gender
+identity and expression, level of experience, education, socio-economic status,
+nationality, personal appearance, race, caste, color, religion, or sexual
+identity and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming,
+diverse, inclusive, and healthy community.
 
 ## Our Standards
 
-Examples of behavior that contributes to creating a positive environment
-include:
+Examples of behavior that contributes to a positive environment for our
+community include:
 
-* Using welcoming and inclusive language
-* Being respectful of differing viewpoints and experiences
-* Gracefully accepting constructive criticism
-* Focusing on what is best for the community
-* Showing empathy towards other community members
+* Demonstrating empathy and kindness toward other people
+* Being respectful of differing opinions, viewpoints, and experiences
+* Giving and gracefully accepting constructive feedback
+* Accepting responsibility and apologizing to those affected by our mistakes,
+  and learning from the experience
+* Focusing on what is best not just for us as individuals, but for the overall
+  community
 
-Examples of unacceptable behavior by participants include:
+Examples of unacceptable behavior include:
 
-* The use of sexualized language or imagery and unwelcome sexual attention or
-  advances
-* Trolling, insulting/derogatory comments, and personal or political attacks
+* The use of sexualized language or imagery, and sexual attention or advances of
+  any kind
+* Trolling, insulting or derogatory comments, and personal or political attacks
 * Public or private harassment
-* Publishing others' private information, such as a physical or electronic
-  address, without explicit permission
+* Publishing others' private information, such as a physical or email address,
+  without their explicit permission
 * Other conduct which could reasonably be considered inappropriate in a
   professional setting
 
-## Our Responsibilities
+## Enforcement Responsibilities
 
-Project maintainers are responsible for clarifying the standards of acceptable
-behavior and are expected to take appropriate and fair corrective action in
-response to any instances of unacceptable behavior.
+Community leaders are responsible for clarifying and enforcing our standards of
+acceptable behavior and will take appropriate and fair corrective action in
+response to any behavior that they deem inappropriate, threatening, offensive,
+or harmful.
 
-Project maintainers have the right and responsibility to remove, edit, or
-reject comments, commits, code, wiki edits, issues, and other contributions
-that are not aligned to this Code of Conduct, or to ban temporarily or
-permanently any contributor for other behaviors that they deem inappropriate,
-threatening, offensive, or harmful.
+Community leaders have the right and responsibility to remove, edit, or reject
+comments, commits, code, wiki edits, issues, and other contributions that are
+not aligned to this Code of Conduct, and will communicate reasons for moderation
+decisions when appropriate.
 
 ## Scope
 
-This Code of Conduct applies both within project spaces and in public spaces
-when an individual is representing the project or its community. Examples of
-representing a project or community include using an official project e-mail
-address, posting via an official social media account, or acting as an appointed
-representative at an online or offline event. Representation of a project may be
-further defined and clarified by project maintainers.
+This Code of Conduct applies within all community spaces, and also applies when
+an individual is officially representing the community in public spaces.
+Examples of representing our community include using an official e-mail address,
+posting via an official social media account, or acting as an appointed
+representative at an online or offline event.
 
 ## Enforcement
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at opensource@scrapinghub.com. All
-complaints will be reviewed and investigated and will result in a response that
-is deemed necessary and appropriate to the circumstances. The project team is
-obligated to maintain confidentiality with regard to the reporter of an incident.
-Further details of specific enforcement policies may be posted separately.
+reported to the community leaders responsible for enforcement at
+opensource@zyte.com.
+All complaints will be reviewed and investigated promptly and fairly.
 
-Project maintainers who do not follow or enforce the Code of Conduct in good
-faith may face temporary or permanent repercussions as determined by other
-members of the project's leadership.
+All community leaders are obligated to respect the privacy and security of the
+reporter of any incident.
+
+## Enforcement Guidelines
+
+Community leaders will follow these Community Impact Guidelines in determining
+the consequences for any action they deem in violation of this Code of Conduct:
+
+### 1. Correction
+
+**Community Impact**: Use of inappropriate language or other behavior deemed
+unprofessional or unwelcome in the community.
+
+**Consequence**: A private, written warning from community leaders, providing
+clarity around the nature of the violation and an explanation of why the
+behavior was inappropriate. A public apology may be requested.
+
+### 2. Warning
+
+**Community Impact**: A violation through a single incident or series of
+actions.
+
+**Consequence**: A warning with consequences for continued behavior. No
+interaction with the people involved, including unsolicited interaction with
+those enforcing the Code of Conduct, for a specified period of time. This
+includes avoiding interactions in community spaces as well as external channels
+like social media. Violating these terms may lead to a temporary or permanent
+ban.
+
+### 3. Temporary Ban
+
+**Community Impact**: A serious violation of community standards, including
+sustained inappropriate behavior.
+
+**Consequence**: A temporary ban from any sort of interaction or public
+communication with the community for a specified period of time. No public or
+private interaction with the people involved, including unsolicited interaction
+with those enforcing the Code of Conduct, is allowed during this period.
+Violating these terms may lead to a permanent ban.
+
+### 4. Permanent Ban
+
+**Community Impact**: Demonstrating a pattern of violation of community
+standards, including sustained inappropriate behavior, harassment of an
+individual, or aggression toward or disparagement of classes of individuals.
+
+**Consequence**: A permanent ban from any sort of public interaction within the
+community.
 
 ## Attribution
 
-This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
-available at [http://contributor-covenant.org/version/1/4][version].
+This Code of Conduct is adapted from the [Contributor Covenant][homepage],
+version 2.1, available at
+[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html][v2.1].
 
-[homepage]: http://contributor-covenant.org
-[version]: http://contributor-covenant.org/version/1/4/
+Community Impact Guidelines were inspired by
+[Mozilla's code of conduct enforcement ladder][Mozilla CoC].
+
+For answers to common questions about this code of conduct, see the FAQ at
+[https://www.contributor-covenant.org/faq][FAQ]. Translations are available at
+[https://www.contributor-covenant.org/translations][translations].
+
+[homepage]: https://www.contributor-covenant.org
+[v2.1]: https://www.contributor-covenant.org/version/2/1/code_of_conduct.html
+[Mozilla CoC]: https://github.com/mozilla/diversity
+[FAQ]: https://www.contributor-covenant.org/faq
+[translations]: https://www.contributor-covenant.org/translations

INSTALL

@@ -1,4 +0,0 @@
-For information about installing Scrapy see:
-
-* docs/intro/install.rst (local file)
-* https://docs.scrapy.org/en/latest/intro/install.html (online version)

INSTALL.md

@@ -0,0 +1,4 @@
+For information about installing Scrapy see:
+
+* [Local docs](docs/intro/install.rst)
+* [Online docs](https://docs.scrapy.org/en/latest/intro/install.html)

MANIFEST.in

@@ -7,6 +7,7 @@ include NEWS
 
 include scrapy/VERSION
 include scrapy/mime.types
+include scrapy/py.typed
 
 include codecov.yml
 include conftest.py

README.rst

@@ -1,3 +1,6 @@
+.. image:: https://scrapy.org/img/scrapylogo.png
+   :target: https://scrapy.org/
+   
 ======
 Scrapy
 ======
@@ -10,9 +13,18 @@ Scrapy
    :target: https://pypi.python.org/pypi/Scrapy
    :alt: Supported Python Versions
 
-.. image:: https://img.shields.io/travis/scrapy/scrapy/master.svg
-   :target: https://travis-ci.org/scrapy/scrapy
-   :alt: Build Status
+.. image:: https://github.com/scrapy/scrapy/workflows/Ubuntu/badge.svg
+   :target: https://github.com/scrapy/scrapy/actions?query=workflow%3AUbuntu
+   :alt: Ubuntu
+
+.. .. image:: https://github.com/scrapy/scrapy/workflows/macOS/badge.svg
+   .. :target: https://github.com/scrapy/scrapy/actions?query=workflow%3AmacOS
+   .. :alt: macOS
+
+
+.. image:: https://github.com/scrapy/scrapy/workflows/Windows/badge.svg
+   :target: https://github.com/scrapy/scrapy/actions?query=workflow%3AWindows
+   :alt: Windows
 
 .. image:: https://img.shields.io/badge/wheel-yes-brightgreen.svg
    :target: https://pypi.python.org/pypi/Scrapy
@@ -30,23 +42,32 @@ Scrapy
 Overview
 ========
 
-Scrapy is a fast high-level web crawling and web scraping framework, used to
+Scrapy is a BSD-licensed fast high-level web crawling and web scraping framework, used to
 crawl websites and extract structured data from their pages. It can be used for
 a wide range of purposes, from data mining to monitoring and automated testing.
 
+Scrapy is maintained by Zyte_ (formerly Scrapinghub) and `many other
+contributors`_.
+
+.. _many other contributors: https://github.com/scrapy/scrapy/graphs/contributors
+.. _Zyte: https://www.zyte.com/
+
 Check the Scrapy homepage at https://scrapy.org for more information,
 including a list of features.
 
+
 Requirements
 ============
 
-* Python 3.6+
+* Python 3.8+
 * Works on Linux, Windows, macOS, BSD
 
 Install
 =======
 
-The quick way::
+The quick way:
+
+.. code:: bash
 
     pip install scrapy
 
@@ -77,11 +98,10 @@ See https://docs.scrapy.org/en/master/contributing.html for details.
 Code of Conduct
 ---------------
 
-Please note that this project is released with a Contributor Code of Conduct
-(see https://github.com/scrapy/scrapy/blob/master/CODE_OF_CONDUCT.md).
+Please note that this project is released with a Contributor `Code of Conduct <https://github.com/scrapy/scrapy/blob/master/CODE_OF_CONDUCT.md>`_.
 
 By participating in this project you agree to abide by its terms.
-Please report unacceptable behavior to opensource@scrapinghub.com.
+Please report unacceptable behavior to opensource@zyte.com.
 
 Companies using Scrapy
 ======================
@@ -91,4 +111,4 @@ See https://scrapy.org/companies/ for a list.
 Commercial Support
 ==================
 
-See https://scrapy.org/support/ for details.
+See https://scrapy.org/support/ for details.

artwork/README.rst

@@ -2,19 +2,19 @@
 Scrapy artwork
 ==============
 
-This folder contains Scrapy artwork resources such as logos and fonts.
+This folder contains the Scrapy artwork resources such as logos and fonts.
 
 scrapy-logo.jpg
 ---------------
 
-Main Scrapy logo, in JPEG format.
+The main Scrapy logo, in JPEG format.
 
 qlassik.zip
 -----------
 
-Font used for Scrapy logo. Homepage: https://www.dafont.com/qlassik.font
+The font used for the Scrapy logo. Homepage: https://www.dafont.com/qlassik.font
 
 scrapy-blog.logo.xcf
 --------------------
 
-The logo used in Scrapy blog, in Gimp format.
+The logo used in the Scrapy blog, in Gimp format.

azure-pipelines.yml

@@ -1,22 +0,0 @@
-variables:
-  TOXENV: py
-pool:
-  vmImage: 'windows-latest'
-strategy:
-  matrix:
-    Python36:
-      python.version: '3.6'
-      TOXENV: windows-pinned
-    Python37:
-      python.version: '3.7'
-    Python38:
-      python.version: '3.8'
-steps:
-- task: UsePythonVersion@0
-  inputs:
-    versionSpec: '$(python.version)'
-  displayName: 'Use Python $(python.version)'
-- script: |
-    pip install -U tox twine wheel codecov
-    tox
-  displayName: 'Run test suite'

conftest.py

@@ -1,27 +1,46 @@
+import platform
+import sys
 from pathlib import Path
 
 import pytest
+from twisted import version as twisted_version
+from twisted.python.versions import Version
+from twisted.web.http import H2_ENABLED
 
+from scrapy.utils.reactor import install_reactor
 from tests.keys import generate_keys
 
 
 def _py_files(folder):
-    return (str(p) for p in Path(folder).rglob('*.py'))
+    return (str(p) for p in Path(folder).rglob("*.py"))
 
 
 collect_ignore = [
     # not a test, but looks like a test
     "scrapy/utils/testsite.py",
+    "tests/ftpserver.py",
+    "tests/mockserver.py",
+    "tests/pipelines.py",
+    "tests/spiders.py",
     # contains scripts to be run by tests/test_crawler.py::CrawlerProcessSubprocess
     *_py_files("tests/CrawlerProcess"),
     # contains scripts to be run by tests/test_crawler.py::CrawlerRunnerSubprocess
     *_py_files("tests/CrawlerRunner"),
 ]
 
-for line in open('tests/ignores.txt'):
-    file_path = line.strip()
-    if file_path and file_path[0] != '#':
-        collect_ignore.append(file_path)
+with Path("tests/ignores.txt").open(encoding="utf-8") as reader:
+    for line in reader:
+        file_path = line.strip()
+        if file_path and file_path[0] != "#":
+            collect_ignore.append(file_path)
+
+if not H2_ENABLED:
+    collect_ignore.extend(
+        (
+            "scrapy/core/downloader/handlers/http2.py",
+            *_py_files("scrapy/core/http2"),
+        )
+    )
 
 
 @pytest.fixture()
@@ -30,17 +49,15 @@ def chdir(tmpdir):
     tmpdir.chdir()
 
 
-def pytest_collection_modifyitems(session, config, items):
-    # Avoid executing tests when executing `--flake8` flag (pytest-flake8)
-    try:
-        from pytest_flake8 import Flake8Item
-        if config.getoption('--flake8'):
-            items[:] = [item for item in items if isinstance(item, Flake8Item)]
-    except ImportError:
-        pass
+def pytest_addoption(parser):
+    parser.addoption(
+        "--reactor",
+        default="default",
+        choices=["default", "asyncio"],
+    )
 
 
-@pytest.fixture(scope='class')
+@pytest.fixture(scope="class")
 def reactor_pytest(request):
     if not request.cls:
         # doctests
@@ -51,8 +68,36 @@ def reactor_pytest(request):
 
 @pytest.fixture(autouse=True)
 def only_asyncio(request, reactor_pytest):
-    if request.node.get_closest_marker('only_asyncio') and reactor_pytest != 'asyncio':
-        pytest.skip('This test is only run with --reactor=asyncio')
+    if request.node.get_closest_marker("only_asyncio") and reactor_pytest != "asyncio":
+        pytest.skip("This test is only run with --reactor=asyncio")
+
+
+@pytest.fixture(autouse=True)
+def only_not_asyncio(request, reactor_pytest):
+    if (
+        request.node.get_closest_marker("only_not_asyncio")
+        and reactor_pytest == "asyncio"
+    ):
+        pytest.skip("This test is only run without --reactor=asyncio")
+
+
+@pytest.fixture(autouse=True)
+def requires_uvloop(request):
+    if not request.node.get_closest_marker("requires_uvloop"):
+        return
+    if sys.implementation.name == "pypy":
+        pytest.skip("uvloop does not support pypy properly")
+    if platform.system() == "Windows":
+        pytest.skip("uvloop does not support Windows")
+    if twisted_version == Version("twisted", 21, 2, 0):
+        pytest.skip("https://twistedmatrix.com/trac/ticket/10106")
+    if sys.version_info >= (3, 12):
+        pytest.skip("uvloop doesn't support Python 3.12 yet")
+
+
+def pytest_configure(config):
+    if config.getoption("--reactor") == "asyncio":
+        install_reactor("twisted.internet.asyncioreactor.AsyncioSelectorReactor")
 
 
 # Generate localhost certificate files, needed by some tests

docs/Makefile

@@ -8,7 +8,7 @@ PYTHON       = python
 SPHINXOPTS   =
 PAPER        =
 SOURCES      =
-SHELL        = /bin/bash
+SHELL        = /usr/bin/env bash
 
 ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees \
                 -D latex_elements.papersize=$(PAPER) \
@@ -86,8 +86,8 @@ coverage: BUILDER = coverage
 coverage: build
 
 htmlview: html
-	 $(PYTHON) -c "import webbrowser, os; webbrowser.open('file://' + \
-	 os.path.realpath('build/html/index.html'))"
+	 $(PYTHON) -c "import webbrowser; from pathlib import Path; \
+	 webbrowser.open(Path('build/html/index.html').resolve().as_uri())"
 
 clean:
 	-rm -rf build/*

docs/README.rst

@@ -43,7 +43,7 @@ This command will fire up your default browser and open the main page of your
 Start over
 ----------
 
-To cleanup all generated documentation files and start from scratch run::
+To clean up all generated documentation files and start from scratch run::
 
     make clean
 

docs/_ext/scrapydocs.py

@@ -1,8 +1,9 @@
-from docutils.parsers.rst.roles import set_classes
+from operator import itemgetter
+
 from docutils import nodes
 from docutils.parsers.rst import Directive
+from docutils.parsers.rst.roles import set_classes
 from sphinx.util.nodes import make_refnode
-from operator import itemgetter
 
 
 class settingslist_node(nodes.General, nodes.Element):
@@ -11,15 +12,15 @@ class settingslist_node(nodes.General, nodes.Element):
 
 class SettingsListDirective(Directive):
     def run(self):
-        return [settingslist_node('')]
+        return [settingslist_node("")]
 
 
 def is_setting_index(node):
-    if node.tagname == 'index':
+    if node.tagname == "index" and node["entries"]:
         # index entries for setting directives look like:
         # [('pair', 'SETTING_NAME; setting', 'std:setting-SETTING_NAME', '')]
-        entry_type, info, refid = node['entries'][0][:3]
-        return entry_type == 'pair' and info.endswith('; setting')
+        entry_type, info, refid = node["entries"][0][:3]
+        return entry_type == "pair" and info.endswith("; setting")
     return False
 
 
@@ -30,14 +31,14 @@ def get_setting_target(node):
 
 def get_setting_name_and_refid(node):
     """Extract setting name from directive index node"""
-    entry_type, info, refid = node['entries'][0][:3]
-    return info.replace('; setting', ''), refid
+    entry_type, info, refid = node["entries"][0][:3]
+    return info.replace("; setting", ""), refid
 
 
 def collect_scrapy_settings_refs(app, doctree):
     env = app.builder.env
 
-    if not hasattr(env, 'scrapy_all_settings'):
+    if not hasattr(env, "scrapy_all_settings"):
         env.scrapy_all_settings = []
 
     for node in doctree.traverse(is_setting_index):
@@ -46,18 +47,23 @@ def collect_scrapy_settings_refs(app, doctree):
 
         setting_name, refid = get_setting_name_and_refid(node)
 
-        env.scrapy_all_settings.append({
-            'docname': env.docname,
-            'setting_name': setting_name,
-            'refid': refid,
-        })
+        env.scrapy_all_settings.append(
+            {
+                "docname": env.docname,
+                "setting_name": setting_name,
+                "refid": refid,
+            }
+        )
 
 
 def make_setting_element(setting_data, app, fromdocname):
-    refnode = make_refnode(app.builder, fromdocname,
-                           todocname=setting_data['docname'],
-                           targetid=setting_data['refid'],
-                           child=nodes.Text(setting_data['setting_name']))
+    refnode = make_refnode(
+        app.builder,
+        fromdocname,
+        todocname=setting_data["docname"],
+        targetid=setting_data["refid"],
+        child=nodes.Text(setting_data["setting_name"]),
+    )
     p = nodes.paragraph()
     p += refnode
 
@@ -71,69 +77,72 @@ def replace_settingslist_nodes(app, doctree, fromdocname):
 
     for node in doctree.traverse(settingslist_node):
         settings_list = nodes.bullet_list()
-        settings_list.extend([make_setting_element(d, app, fromdocname)
-                              for d in sorted(env.scrapy_all_settings,
-                                              key=itemgetter('setting_name'))
-                              if fromdocname != d['docname']])
+        settings_list.extend(
+            [
+                make_setting_element(d, app, fromdocname)
+                for d in sorted(env.scrapy_all_settings, key=itemgetter("setting_name"))
+                if fromdocname != d["docname"]
+            ]
+        )
         node.replace_self(settings_list)
 
 
 def setup(app):
     app.add_crossref_type(
-        directivename = "setting",
-        rolename      = "setting",
-        indextemplate = "pair: %s; setting",
+        directivename="setting",
+        rolename="setting",
+        indextemplate="pair: %s; setting",
     )
     app.add_crossref_type(
-        directivename = "signal",
-        rolename      = "signal",
-        indextemplate = "pair: %s; signal",
+        directivename="signal",
+        rolename="signal",
+        indextemplate="pair: %s; signal",
     )
     app.add_crossref_type(
-        directivename = "command",
-        rolename      = "command",
-        indextemplate = "pair: %s; command",
+        directivename="command",
+        rolename="command",
+        indextemplate="pair: %s; command",
     )
     app.add_crossref_type(
-        directivename = "reqmeta",
-        rolename      = "reqmeta",
-        indextemplate = "pair: %s; reqmeta",
+        directivename="reqmeta",
+        rolename="reqmeta",
+        indextemplate="pair: %s; reqmeta",
     )
-    app.add_role('source', source_role)
-    app.add_role('commit', commit_role)
-    app.add_role('issue', issue_role)
-    app.add_role('rev', rev_role)
+    app.add_role("source", source_role)
+    app.add_role("commit", commit_role)
+    app.add_role("issue", issue_role)
+    app.add_role("rev", rev_role)
 
     app.add_node(settingslist_node)
-    app.add_directive('settingslist', SettingsListDirective)
+    app.add_directive("settingslist", SettingsListDirective)
 
-    app.connect('doctree-read', collect_scrapy_settings_refs)
-    app.connect('doctree-resolved', replace_settingslist_nodes)
+    app.connect("doctree-read", collect_scrapy_settings_refs)
+    app.connect("doctree-resolved", replace_settingslist_nodes)
 
 
 def source_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
-    ref = 'https://github.com/scrapy/scrapy/blob/master/' + text
+    ref = "https://github.com/scrapy/scrapy/blob/master/" + text
     set_classes(options)
     node = nodes.reference(rawtext, text, refuri=ref, **options)
     return [node], []
 
 
 def issue_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
-    ref = 'https://github.com/scrapy/scrapy/issues/' + text
+    ref = "https://github.com/scrapy/scrapy/issues/" + text
     set_classes(options)
-    node = nodes.reference(rawtext, 'issue ' + text, refuri=ref, **options)
+    node = nodes.reference(rawtext, "issue " + text, refuri=ref, **options)
     return [node], []
 
 
 def commit_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
-    ref = 'https://github.com/scrapy/scrapy/commit/' + text
+    ref = "https://github.com/scrapy/scrapy/commit/" + text
     set_classes(options)
-    node = nodes.reference(rawtext, 'commit ' + text, refuri=ref, **options)
+    node = nodes.reference(rawtext, "commit " + text, refuri=ref, **options)
     return [node], []
 
 
 def rev_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
-    ref = 'http://hg.scrapy.org/scrapy/changeset/' + text
+    ref = "http://hg.scrapy.org/scrapy/changeset/" + text
     set_classes(options)
-    node = nodes.reference(rawtext, 'r' + text, refuri=ref, **options)
+    node = nodes.reference(rawtext, "r" + text, refuri=ref, **options)
     return [node], []

docs/_static/custom.css

@@ -0,0 +1,10 @@
+/* Move lists closer to their introducing paragraph */
+.rst-content .section ol p, .rst-content .section ul p {
+    margin-bottom: 0px;
+}
+.rst-content p + ol, .rst-content p + ul {
+    margin-top: -18px; /* Compensates margin-top: 24px of p  */
+}
+.rst-content dl p + ol, .rst-content dl p + ul {
+    margin-top: -6px; /* Compensates margin-top: 12px of p  */
+}

docs/_static/selectors-sample1.html

@@ -1,16 +1,17 @@
-<html>
- <head>
-  <base href='http://example.com/' />
-  <title>Example website</title>
- </head>
- <body>
-  <div id='images'>
-   <a href='image1.html'>Name: My image 1 <br /><img src='image1_thumb.jpg' /></a>
-   <a href='image2.html'>Name: My image 2 <br /><img src='image2_thumb.jpg' /></a>
-   <a href='image3.html'>Name: My image 3 <br /><img src='image3_thumb.jpg' /></a>
-   <a href='image4.html'>Name: My image 4 <br /><img src='image4_thumb.jpg' /></a>
-   <a href='image5.html'>Name: My image 5 <br /><img src='image5_thumb.jpg' /></a>
-  </div>
- </body>
-</html>
+<!DOCTYPE html>
 
+<html>
+  <head>
+    <base href='http://example.com/' />
+    <title>Example website</title>
+  </head>
+  <body>
+    <div id='images'>
+      <a href='image1.html'>Name: My image 1 <br /><img src='image1_thumb.jpg' alt='image1'/></a>
+      <a href='image2.html'>Name: My image 2 <br /><img src='image2_thumb.jpg' alt='image2'/></a>
+      <a href='image3.html'>Name: My image 3 <br /><img src='image3_thumb.jpg' alt='image3'/></a>
+      <a href='image4.html'>Name: My image 4 <br /><img src='image4_thumb.jpg' alt='image4'/></a>
+      <a href='image5.html'>Name: My image 5 <br /><img src='image5_thumb.jpg' alt='image5'/></a>
+    </div>
+  </body>
+</html>

docs/_templates/layout.html

@@ -1,16 +0,0 @@
-{% extends "!layout.html" %}
-
-{% block footer %}
-{{ super() }}
-<script type="text/javascript">
-!function(){var analytics=window.analytics=window.analytics||[];if(!analytics.initialize)if(analytics.invoked)window.console&&console.error&&console.error("Segment snippet included twice.");else{analytics.invoked=!0;analytics.methods=["trackSubmit","trackClick","trackLink","trackForm","pageview","identify","reset","group","track","ready","alias","page","once","off","on"];analytics.factory=function(t){return function(){var e=Array.prototype.slice.call(arguments);e.unshift(t);analytics.push(e);return analytics}};for(var t=0;t<analytics.methods.length;t++){var e=analytics.methods[t];analytics[e]=analytics.factory(e)}analytics.load=function(t){var e=document.createElement("script");e.type="text/javascript";e.async=!0;e.src=("https:"===document.location.protocol?"https://":"http://")+"cdn.segment.com/analytics.js/v1/"+t+"/analytics.min.js";var n=document.getElementsByTagName("script")[0];n.parentNode.insertBefore(e,n)};analytics.SNIPPET_VERSION="3.1.0";
-analytics.load("8UDQfnf3cyFSTsM4YANnW5sXmgZVILbA");
-analytics.page();
-}}();
-
-analytics.ready(function () {
-    ga('require', 'linker');
-    ga('linker:autoLink', ['scrapinghub.com', 'crawlera.com']);
-});
-</script>
-{% endblock %}

docs/_tests/quotes.html

@@ -273,7 +273,7 @@
                 Quotes by: <a href="https://www.goodreads.com/quotes">GoodReads.com</a>
             </p>
             <p class="copyright">
-                Made with <span class='sh-red'>❤</span> by <a href="https://scrapinghub.com">Scrapinghub</a>
+                Made with <span class='sh-red'>❤</span> by <a href="https://www.zyte.com">Zyte</a>
             </p>
         </div>
     </footer>

docs/_tests/quotes1.html

@@ -273,7 +273,7 @@
                 Quotes by: <a href="https://www.goodreads.com/quotes">GoodReads.com</a>
             </p>
             <p class="copyright">
-                Made with <span class='sh-red'>❤</span> by <a href="https://scrapinghub.com">Scrapinghub</a>
+                Made with <span class='sh-red'>❤</span> by <a href="https://www.zyte.com">Zyte</a>
             </p>
         </div>
     </footer>

docs/conf.py

@@ -11,13 +11,12 @@
 
 import sys
 from datetime import datetime
-from os import path
+from pathlib import Path
 
 # If your extensions are in another directory, add it here. If the directory
-# is relative to the documentation root, use os.path.abspath to make it
-# absolute, like shown here.
-sys.path.append(path.join(path.dirname(__file__), "_ext"))
-sys.path.insert(0, path.dirname(path.dirname(__file__)))
+# is relative to the documentation root, use Path.absolute to make it absolute.
+sys.path.append(str(Path(__file__).parent / "_ext"))
+sys.path.insert(0, str(Path(__file__).parent.parent))
 
 
 # General configuration
@@ -26,30 +25,30 @@ sys.path.insert(0, path.dirname(path.dirname(__file__)))
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
-    'hoverxref.extension',
-    'notfound.extension',
-    'scrapydocs',
-    'sphinx.ext.autodoc',
-    'sphinx.ext.coverage',
-    'sphinx.ext.intersphinx',
-    'sphinx.ext.viewcode',
+    "hoverxref.extension",
+    "notfound.extension",
+    "scrapydocs",
+    "sphinx.ext.autodoc",
+    "sphinx.ext.coverage",
+    "sphinx.ext.intersphinx",
+    "sphinx.ext.viewcode",
 ]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
-#source_encoding = 'utf-8'
+# source_encoding = 'utf-8'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'Scrapy'
-copyright = f'2008–{datetime.now().year}, Scrapy developers'
+project = "Scrapy"
+copyright = f"2008–{datetime.now().year}, Scrapy developers"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -58,50 +57,51 @@ copyright = f'2008–{datetime.now().year}, Scrapy developers'
 # The short X.Y version.
 try:
     import scrapy
-    version = '.'.join(map(str, scrapy.version_info[:2]))
+
+    version = ".".join(map(str, scrapy.version_info[:2]))
     release = scrapy.__version__
 except ImportError:
-    version = ''
-    release = ''
+    version = ""
+    release = ""
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-language = 'en'
+language = "en"
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
-#today = ''
+# today = ''
 # Else, today_fmt is used as the format for a strftime call.
-#today_fmt = '%B %d, %Y'
+# today_fmt = '%B %d, %Y'
 
 # List of documents that shouldn't be included in the build.
-#unused_docs = []
+# unused_docs = []
 
-exclude_patterns = ['build']
+exclude_patterns = ["build"]
 
 # List of directories, relative to source directory, that shouldn't be searched
 # for source files.
-exclude_trees = ['.build']
+exclude_trees = [".build"]
 
 # The reST default role (used for this markup: `text`) to use for all documents.
-#default_role = None
+# default_role = None
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
-#add_function_parentheses = True
+# add_function_parentheses = True
 
 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
-#add_module_names = True
+# add_module_names = True
 
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
-#show_authors = False
+# show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # List of Sphinx warnings that will not be raised
-suppress_warnings = ['epub.unknown_project_files']
+suppress_warnings = ["epub.unknown_project_files"]
 
 
 # Options for HTML output
@@ -109,19 +109,19 @@ suppress_warnings = ['epub.unknown_project_files']
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'sphinx_rtd_theme'
+html_theme = "sphinx_rtd_theme"
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-#html_theme_options = {}
+# html_theme_options = {}
 
 # Add any paths that contain custom themes here, relative to this directory.
 # Add path to the RTD explicitly to robustify builds (otherwise might
 # fail in a clean Debian build env)
 import sphinx_rtd_theme
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
+html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # The style sheet to use for HTML and HTML Help pages. A file of that name
 # must exist either in Sphinx' static/ path, or in one of the custom paths
@@ -130,44 +130,44 @@ html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-#html_title = None
+# html_title = None
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
-#html_short_title = None
+# html_short_title = None
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-#html_logo = None
+# html_logo = None
 
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.
-#html_favicon = None
+# html_favicon = None
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+html_static_path = ["_static"]
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-html_last_updated_fmt = '%b %d, %Y'
+html_last_updated_fmt = "%b %d, %Y"
 
 # Custom sidebar templates, maps document names to template names.
-#html_sidebars = {}
+# html_sidebars = {}
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-#html_additional_pages = {}
+# html_additional_pages = {}
 
 # If false, no module index is generated.
-#html_use_modindex = True
+# html_use_modindex = True
 
 # If false, no index is generated.
-#html_use_index = True
+# html_use_index = True
 
 # If true, the index is split into individual pages for each letter.
-#html_split_index = False
+# html_split_index = False
 
 # If true, the reST sources are included in the HTML build as _sources/<name>.
 html_copy_source = True
@@ -175,47 +175,50 @@ html_copy_source = True
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-#html_use_opensearch = ''
+# html_use_opensearch = ''
 
 # If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
-#html_file_suffix = ''
+# html_file_suffix = ''
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'Scrapydoc'
+htmlhelp_basename = "Scrapydoc"
+
+html_css_files = [
+    "custom.css",
+]
 
 
 # Options for LaTeX output
 # ------------------------
 
 # The paper size ('letter' or 'a4').
-#latex_paper_size = 'letter'
+# latex_paper_size = 'letter'
 
 # The font size ('10pt', '11pt' or '12pt').
-#latex_font_size = '10pt'
+# latex_font_size = '10pt'
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, document class [howto/manual]).
 latex_documents = [
-  ('index', 'Scrapy.tex', 'Scrapy Documentation',
-   'Scrapy developers', 'manual'),
+    ("index", "Scrapy.tex", "Scrapy Documentation", "Scrapy developers", "manual"),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
-#latex_logo = None
+# latex_logo = None
 
 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
-#latex_use_parts = False
+# latex_use_parts = False
 
 # Additional stuff for the LaTeX preamble.
-#latex_preamble = ''
+# latex_preamble = ''
 
 # Documents to append as an appendix to all manuals.
-#latex_appendices = []
+# latex_appendices = []
 
 # If false, no module index is generated.
-#latex_use_modindex = True
+# latex_use_modindex = True
 
 
 # Options for the linkcheck builder
@@ -224,8 +227,9 @@ latex_documents = [
 # A list of regular expressions that match URIs that should not be checked when
 # doing a linkcheck build.
 linkcheck_ignore = [
-    'http://localhost:\d+', 'http://hg.scrapy.org',
-    'http://directory.google.com/'
+    "http://localhost:\d+",
+    "http://hg.scrapy.org",
+    "http://directory.google.com/",
 ]
 
 
@@ -235,45 +239,35 @@ coverage_ignore_pyobjects = [
     # Contract’s add_pre_hook and add_post_hook are not documented because
     # they should be transparent to contract developers, for whom pre_hook and
     # post_hook should be the actual concern.
-    r'\bContract\.add_(pre|post)_hook$',
-
+    r"\bContract\.add_(pre|post)_hook$",
     # ContractsManager is an internal class, developers are not expected to
     # interact with it directly in any way.
-    r'\bContractsManager\b$',
-
+    r"\bContractsManager\b$",
     # For default contracts we only want to document their general purpose in
     # their __init__ method, the methods they reimplement to achieve that purpose
     # should be irrelevant to developers using those contracts.
-    r'\w+Contract\.(adjust_request_args|(pre|post)_process)$',
-
+    r"\w+Contract\.(adjust_request_args|(pre|post)_process)$",
     # Methods of downloader middlewares are not documented, only the classes
     # themselves, since downloader middlewares are controlled through Scrapy
     # settings.
-    r'^scrapy\.downloadermiddlewares\.\w*?\.(\w*?Middleware|DownloaderStats)\.',
-
+    r"^scrapy\.downloadermiddlewares\.\w*?\.(\w*?Middleware|DownloaderStats)\.",
     # Base classes of downloader middlewares are implementation details that
     # are not meant for users.
-    r'^scrapy\.downloadermiddlewares\.\w*?\.Base\w*?Middleware',
-
+    r"^scrapy\.downloadermiddlewares\.\w*?\.Base\w*?Middleware",
     # Private exception used by the command-line interface implementation.
-    r'^scrapy\.exceptions\.UsageError',
-
+    r"^scrapy\.exceptions\.UsageError",
     # Methods of BaseItemExporter subclasses are only documented in
     # BaseItemExporter.
-    r'^scrapy\.exporters\.(?!BaseItemExporter\b)\w*?\.',
-
+    r"^scrapy\.exporters\.(?!BaseItemExporter\b)\w*?\.",
     # Extension behavior is only modified through settings. Methods of
     # extension classes, as well as helper functions, are implementation
     # details that are not documented.
-    r'^scrapy\.extensions\.[a-z]\w*?\.[A-Z]\w*?\.',  # methods
-    r'^scrapy\.extensions\.[a-z]\w*?\.[a-z]',  # helper functions
-
+    r"^scrapy\.extensions\.[a-z]\w*?\.[A-Z]\w*?\.",  # methods
+    r"^scrapy\.extensions\.[a-z]\w*?\.[a-z]",  # helper functions
     # Never documented before, and deprecated now.
-    r'^scrapy\.item\.DictItem$',
-    r'^scrapy\.linkextractors\.FilteringLinkExtractor$',
-
+    r"^scrapy\.linkextractors\.FilteringLinkExtractor$",
     # Implementation detail of LxmlLinkExtractor
-    r'^scrapy\.linkextractors\.lxmlhtml\.LxmlParserLinkExtractor',
+    r"^scrapy\.linkextractors\.lxmlhtml\.LxmlParserLinkExtractor",
 ]
 
 
@@ -281,17 +275,20 @@ coverage_ignore_pyobjects = [
 # -------------------------------------
 
 intersphinx_mapping = {
-    'attrs': ('https://www.attrs.org/en/stable/', None),
-    'coverage': ('https://coverage.readthedocs.io/en/stable', None),
-    'cssselect': ('https://cssselect.readthedocs.io/en/latest', None),
-    'itemloaders': ('https://itemloaders.readthedocs.io/en/latest/', None),
-    'pytest': ('https://docs.pytest.org/en/latest', None),
-    'python': ('https://docs.python.org/3', None),
-    'sphinx': ('https://www.sphinx-doc.org/en/master', None),
-    'tox': ('https://tox.readthedocs.io/en/latest', None),
-    'twisted': ('https://twistedmatrix.com/documents/current', None),
-    'twistedapi': ('https://twistedmatrix.com/documents/current/api', None),
+    "attrs": ("https://www.attrs.org/en/stable/", None),
+    "coverage": ("https://coverage.readthedocs.io/en/latest", None),
+    "cryptography": ("https://cryptography.io/en/latest/", None),
+    "cssselect": ("https://cssselect.readthedocs.io/en/latest", None),
+    "itemloaders": ("https://itemloaders.readthedocs.io/en/latest/", None),
+    "pytest": ("https://docs.pytest.org/en/latest", None),
+    "python": ("https://docs.python.org/3", None),
+    "sphinx": ("https://www.sphinx-doc.org/en/master", None),
+    "tox": ("https://tox.wiki/en/latest/", None),
+    "twisted": ("https://docs.twisted.org/en/stable/", None),
+    "twistedapi": ("https://docs.twisted.org/en/stable/api/", None),
+    "w3lib": ("https://w3lib.readthedocs.io/en/latest", None),
 }
+intersphinx_disabled_reftypes = []
 
 
 # Options for sphinx-hoverxref options
@@ -300,21 +297,25 @@ intersphinx_mapping = {
 hoverxref_auto_ref = True
 hoverxref_role_types = {
     "class": "tooltip",
+    "command": "tooltip",
     "confval": "tooltip",
     "hoverxref": "tooltip",
     "mod": "tooltip",
     "ref": "tooltip",
+    "reqmeta": "tooltip",
+    "setting": "tooltip",
+    "signal": "tooltip",
 }
-hoverxref_roles = ['command', 'reqmeta', 'setting', 'signal']
+hoverxref_roles = ["command", "reqmeta", "setting", "signal"]
 
 
 def setup(app):
-    app.connect('autodoc-skip-member', maybe_skip_member)
+    app.connect("autodoc-skip-member", maybe_skip_member)
 
 
 def maybe_skip_member(app, what, name, obj, skip, options):
     if not skip:
         # autodocs was generating a text "alias of" for the following members
         # https://github.com/sphinx-doc/sphinx/issues/4422
-        return name in {'default_item_class', 'default_selector_class'}
+        return name in {"default_item_class", "default_selector_class"}
     return skip

docs/conftest.py

@@ -1,29 +1,34 @@
-import os
 from doctest import ELLIPSIS, NORMALIZE_WHITESPACE
+from pathlib import Path
 
-from scrapy.http.response.html import HtmlResponse
 from sybil import Sybil
-from sybil.parsers.codeblock import CodeBlockParser
 from sybil.parsers.doctest import DocTestParser
 from sybil.parsers.skip import skip
 
+try:
+    # >2.0.1
+    from sybil.parsers.codeblock import PythonCodeBlockParser
+except ImportError:
+    from sybil.parsers.codeblock import CodeBlockParser as PythonCodeBlockParser
 
-def load_response(url, filename):
-    input_path = os.path.join(os.path.dirname(__file__), '_tests', filename)
-    with open(input_path, 'rb') as input_file:
-        return HtmlResponse(url, body=input_file.read())
+from scrapy.http.response.html import HtmlResponse
+
+
+def load_response(url: str, filename: str) -> HtmlResponse:
+    input_path = Path(__file__).parent / "_tests" / filename
+    return HtmlResponse(url, body=input_path.read_bytes())
 
 
 def setup(namespace):
-    namespace['load_response'] = load_response
+    namespace["load_response"] = load_response
 
 
 pytest_collect_file = Sybil(
     parsers=[
         DocTestParser(optionflags=ELLIPSIS | NORMALIZE_WHITESPACE),
-        CodeBlockParser(future_imports=['print_function']),
+        PythonCodeBlockParser(future_imports=["print_function"]),
         skip,
     ],
-    pattern='*.rst',
+    pattern="*.rst",
     setup=setup,
 ).pytest()

docs/contributing.rst

@@ -11,10 +11,6 @@ Contributing to Scrapy
 
 There are many ways to contribute to Scrapy. Here are some of them:
 
-* Blog about Scrapy. Tell the world how you're using Scrapy. This will help
-  newcomers with more examples and will help the Scrapy project to increase its
-  visibility.
-
 * Report bugs and request features in the `issue tracker`_, trying to follow
   the guidelines detailed in `Reporting bugs`_ below.
 
@@ -22,13 +18,16 @@ There are many ways to contribute to Scrapy. Here are some of them:
   :ref:`writing-patches` and `Submitting patches`_ below for details on how to
   write and submit a patch.
 
+* Blog about Scrapy. Tell the world how you're using Scrapy. This will help
+  newcomers with more examples and will help the Scrapy project to increase its
+  visibility.
+
 * Join the `Scrapy subreddit`_ and share your ideas on how to
   improve Scrapy. We're always open to suggestions.
 
 * Answer Scrapy questions at
   `Stack Overflow <https://stackoverflow.com/questions/tagged/scrapy>`__.
 
-
 Reporting bugs
 ==============
 
@@ -49,7 +48,7 @@ guidelines when you're going to report a new bug.
   (use "scrapy" tag).
 
 * check the `open issues`_ to see if the issue has already been reported. If it
-  has, don't dismiss the report, but check the ticket history and comments. If 
+  has, don't dismiss the report, but check the ticket history and comments. If
   you have additional useful information, please leave a comment, or consider
   :ref:`sending a pull request <writing-patches>` with a fix.
 
@@ -80,6 +79,13 @@ guidelines when you're going to report a new bug.
 Writing patches
 ===============
 
+Scrapy has a list of `good first issues`_ and `help wanted issues`_ that you
+can work on. These issues are a great way to get started with contributing to
+Scrapy. If you're new to the codebase, you may want to focus on documentation
+or testing-related issues, as they are always useful and can help you get
+more familiar with the project. You can also check Scrapy's `test coverage`_
+to see which areas may benefit from more tests.
+
 The better a patch is written, the higher the chances that it'll get accepted and the sooner it will be merged.
 
 Well-written patches should:
@@ -169,16 +175,43 @@ Coding style
 Please follow these coding conventions when writing code for inclusion in
 Scrapy:
 
-* Unless otherwise specified, follow :pep:`8`.
-
-* It's OK to use lines longer than 79 chars if it improves the code
-  readability.
+* We use `black <https://black.readthedocs.io/en/stable/>`_ for code formatting.
+  There is a hook in the pre-commit config
+  that will automatically format your code before every commit. You can also
+  run black manually with ``tox -e black``.
 
 * Don't put your name in the code you contribute; git provides enough
   metadata to identify author of the code.
   See https://help.github.com/en/github/using-git/setting-your-username-in-git for
   setup instructions.
 
+.. _scrapy-pre-commit:
+
+Pre-commit
+==========
+
+We use `pre-commit`_ to automatically address simple code issues before every
+commit.
+
+.. _pre-commit: https://pre-commit.com/
+
+After your create a local clone of your fork of the Scrapy repository:
+
+#.  `Install pre-commit <https://pre-commit.com/#installation>`_.
+
+#.  On the root of your local clone of the Scrapy repository, run the following
+    command:
+
+    .. code-block:: bash
+
+       pre-commit install
+
+Now pre-commit will check your changes every time you create a Git commit. Upon
+finding issues, pre-commit aborts your commit, and either fixes those issues
+automatically, or only reports them to you. If it fixes those issues
+automatically, creating your commit again should succeed. Otherwise, you may
+need to address the corresponding issues manually first.
+
 .. _documentation-policies:
 
 Documentation policies
@@ -214,7 +247,7 @@ Tests
 =====
 
 Tests are implemented using the :doc:`Twisted unit-testing framework
-<twisted:core/development/policy/test-standard>`. Running tests requires
+<twisted:development/test-standard>`. Running tests requires
 :doc:`tox <tox:index>`.
 
 .. _running-tests:
@@ -232,15 +265,15 @@ To run a specific test (say ``tests/test_loader.py``) use:
 
 To run the tests on a specific :doc:`tox <tox:index>` environment, use
 ``-e <name>`` with an environment name from ``tox.ini``. For example, to run
-the tests with Python 3.6 use::
+the tests with Python 3.10 use::
 
-    tox -e py36
+    tox -e py310
 
 You can also specify a comma-separated list of environments, and use :ref:`tox’s
 parallel mode <tox:parallel_mode>` to run the tests on multiple environments in
 parallel::
 
-    tox -e py36,py38 -p auto
+    tox -e py39,py310 -p auto
 
 To pass command-line options to :doc:`pytest <pytest:index>`, add them after
 ``--`` in your call to :doc:`tox <tox:index>`. Using ``--`` overrides the
@@ -250,9 +283,9 @@ default positional arguments (``scrapy tests``) after ``--`` as well::
     tox -- scrapy tests -x  # stop after first failure
 
 You can also use the `pytest-xdist`_ plugin. For example, to run all tests on
-the Python 3.6 :doc:`tox <tox:index>` environment using all your CPU cores::
+the Python 3.10 :doc:`tox <tox:index>` environment using all your CPU cores::
 
-    tox -e py36 -- scrapy tests -n auto
+    tox -e py310 -- scrapy tests -n auto
 
 To see coverage report install :doc:`coverage <coverage:index>`
 (``pip install coverage``) and run:
@@ -287,3 +320,6 @@ And their unit-tests are in::
 .. _PEP 257: https://www.python.org/dev/peps/pep-0257/
 .. _pull request: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request
 .. _pytest-xdist: https://github.com/pytest-dev/pytest-xdist
+.. _good first issues: https://github.com/scrapy/scrapy/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22
+.. _help wanted issues: https://github.com/scrapy/scrapy/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22
+.. _test coverage: https://app.codecov.io/gh/scrapy/scrapy

docs/faq.rst

@@ -35,8 +35,10 @@ for parsing HTML responses in Scrapy callbacks.
 You just have to feed the response's body into a ``BeautifulSoup`` object
 and extract whatever data you need from it.
 
-Here's an example spider using BeautifulSoup API, with ``lxml`` as the HTML parser::
+Here's an example spider using BeautifulSoup API, with ``lxml`` as the HTML parser:
 
+.. skip: next
+.. code-block:: python
 
     from bs4 import BeautifulSoup
     import scrapy
@@ -45,17 +47,12 @@ Here's an example spider using BeautifulSoup API, with ``lxml`` as the HTML pars
     class ExampleSpider(scrapy.Spider):
         name = "example"
         allowed_domains = ["example.com"]
-        start_urls = (
-            'http://www.example.com/',
-        )
+        start_urls = ("http://www.example.com/",)
 
         def parse(self, response):
             # use lxml to get decent HTML parsing speed
-            soup = BeautifulSoup(response.text, 'lxml')
-            yield {
-                "url": response.url,
-                "title": soup.h1.string
-            }
+            soup = BeautifulSoup(response.text, "lxml")
+            yield {"url": response.url, "title": soup.h1.string}
 
 .. note::
 
@@ -94,15 +91,6 @@ How can I scrape an item with attributes in different pages?
 
 See :ref:`topics-request-response-ref-request-callback-arguments`.
 
-
-Scrapy crashes with: ImportError: No module named win32api
-----------------------------------------------------------
-
-You need to install `pywin32`_ because of `this Twisted bug`_.
-
-.. _pywin32: https://sourceforge.net/projects/pywin32/
-.. _this Twisted bug: https://twistedmatrix.com/trac/ticket/3707
-
 How can I simulate a user login in my spider?
 ---------------------------------------------
 
@@ -118,11 +106,13 @@ basically means that it crawls in `DFO order`_. This order is more convenient
 in most cases.
 
 If you do want to crawl in true `BFO order`_, you can do it by
-setting the following settings::
+setting the following settings:
+
+.. code-block:: python
 
     DEPTH_PRIORITY = 1
-    SCHEDULER_DISK_QUEUE = 'scrapy.squeues.PickleFifoDiskQueue'
-    SCHEDULER_MEMORY_QUEUE = 'scrapy.squeues.FifoMemoryQueue'
+    SCHEDULER_DISK_QUEUE = "scrapy.squeues.PickleFifoDiskQueue"
+    SCHEDULER_MEMORY_QUEUE = "scrapy.squeues.FifoMemoryQueue"
 
 While pending requests are below the configured values of
 :setting:`CONCURRENT_REQUESTS`, :setting:`CONCURRENT_REQUESTS_PER_DOMAIN` or
@@ -145,6 +135,43 @@ How can I make Scrapy consume less memory?
 
 See previous question.
 
+How can I prevent memory errors due to many allowed domains?
+------------------------------------------------------------
+
+If you have a spider with a long list of
+:attr:`~scrapy.Spider.allowed_domains` (e.g. 50,000+), consider
+replacing the default
+:class:`~scrapy.spidermiddlewares.offsite.OffsiteMiddleware` spider middleware
+with a :ref:`custom spider middleware <custom-spider-middleware>` that requires
+less memory. For example:
+
+-   If your domain names are similar enough, use your own regular expression
+    instead joining the strings in
+    :attr:`~scrapy.Spider.allowed_domains` into a complex regular
+    expression.
+
+-   If you can `meet the installation requirements`_, use pyre2_ instead of
+    Python’s re_ to compile your URL-filtering regular expression. See
+    :issue:`1908`.
+
+See also other suggestions at `StackOverflow`_.
+
+.. note:: Remember to disable
+   :class:`scrapy.spidermiddlewares.offsite.OffsiteMiddleware` when you enable
+   your custom implementation:
+
+   .. code-block:: python
+
+       SPIDER_MIDDLEWARES = {
+           "scrapy.spidermiddlewares.offsite.OffsiteMiddleware": None,
+           "myproject.middlewares.CustomOffsiteMiddleware": 500,
+       }
+
+.. _meet the installation requirements: https://github.com/andreasvc/pyre2#installation
+.. _pyre2: https://github.com/andreasvc/pyre2
+.. _re: https://docs.python.org/library/re.html
+.. _StackOverflow: https://stackoverflow.com/q/36440681/939364
+
 Can I use Basic HTTP Authentication in my spiders?
 --------------------------------------------------
 
@@ -204,16 +231,20 @@ Can I return (Twisted) deferreds from signal handlers?
 Some signals support returning deferreds from their handlers, others don't. See
 the :ref:`topics-signals-ref` to know which ones.
 
-What does the response status code 999 means?
----------------------------------------------
+What does the response status code 999 mean?
+--------------------------------------------
 
 999 is a custom response status code used by Yahoo sites to throttle requests.
 Try slowing down the crawling speed by using a download delay of ``2`` (or
-higher) in your spider::
+higher) in your spider:
+
+.. code-block:: python
+
+    from scrapy.spiders import CrawlSpider
+
 
     class MySpider(CrawlSpider):
-
-        name = 'myspider'
+        name = "myspider"
 
         download_delay = 2
 
@@ -315,6 +346,7 @@ I'm scraping a XML document and my XPath selector doesn't return any items
 
 You may need to remove namespaces. See :ref:`removing-namespaces`.
 
+
 .. _faq-split-item:
 
 How to split an item into multiple items in an item pipeline?
@@ -324,19 +356,21 @@ How to split an item into multiple items in an item pipeline?
 input item. :ref:`Create a spider middleware <custom-spider-middleware>`
 instead, and use its
 :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output`
-method for this purpose. For example::
+method for this purpose. For example:
+
+.. code-block:: python
 
     from copy import deepcopy
 
     from itemadapter import is_item, ItemAdapter
 
-    class MultiplyItemsMiddleware:
 
+    class MultiplyItemsMiddleware:
         def process_spider_output(self, response, result, spider):
             for item in result:
                 if is_item(item):
                     adapter = ItemAdapter(item)
-                    for _ in range(adapter['multiply_by']):
+                    for _ in range(adapter["multiply_by"]):
                         yield deepcopy(item)
 
 Does Scrapy support IPv6 addresses?
@@ -363,14 +397,26 @@ How can I cancel the download of a given response?
 --------------------------------------------------
 
 In some situations, it might be useful to stop the download of a certain response.
-For instance, if you only need the first part of a large response and you would like
-to save resources by avoiding the download of the whole body.
-In that case, you could attach a handler to the :class:`~scrapy.signals.bytes_received`
-signal and raise a :exc:`~scrapy.exceptions.StopDownload` exception. Please refer to
-the :ref:`topics-stop-response-download` topic for additional information and examples.
+For instance, sometimes you can determine whether or not you need the full contents
+of a response by inspecting its headers or the first bytes of its body. In that case,
+you could save resources by attaching a handler to the :class:`~scrapy.signals.bytes_received`
+or :class:`~scrapy.signals.headers_received` signals and raising a
+:exc:`~scrapy.exceptions.StopDownload` exception. Please refer to the
+:ref:`topics-stop-response-download` topic for additional information and examples.
+
+
+Running ``runspider`` I get ``error: No spider found in file: <filename>``
+--------------------------------------------------------------------------
+
+This may happen if your Scrapy project has a spider module with a name that
+conflicts with the name of one of the `Python standard library modules`_, such
+as ``csv.py`` or ``os.py``, or any `Python package`_ that you have installed.
+See :issue:`2680`.
 
 
 .. _has been reported: https://github.com/scrapy/scrapy/issues/2905
+.. _Python standard library modules: https://docs.python.org/py-modindex.html
+.. _Python package: https://pypi.org/
 .. _user agents: https://en.wikipedia.org/wiki/User_agent
 .. _LIFO: https://en.wikipedia.org/wiki/Stack_(abstract_data_type)
 .. _DFO order: https://en.wikipedia.org/wiki/Depth-first_search

docs/index.rst

@@ -12,6 +12,8 @@ testing.
 .. _web crawling: https://en.wikipedia.org/wiki/Web_crawler
 .. _web scraping: https://en.wikipedia.org/wiki/Web_scraping
 
+.. _getting-help:
+
 Getting help
 ============
 
@@ -24,12 +26,14 @@ Having trouble? We'd like to help!
 * Search for questions on the archives of the `scrapy-users mailing list`_.
 * Ask a question in the `#scrapy IRC channel`_,
 * Report bugs with Scrapy in our `issue tracker`_.
+* Join the Discord community `Scrapy Discord`_.
 
 .. _scrapy-users mailing list: https://groups.google.com/forum/#!forum/scrapy-users
 .. _Scrapy subreddit: https://www.reddit.com/r/scrapy/
 .. _StackOverflow using the scrapy tag: https://stackoverflow.com/tags/scrapy
 .. _#scrapy IRC channel: irc://irc.freenode.net/scrapy
 .. _issue tracker: https://github.com/scrapy/scrapy/issues
+.. _Scrapy Discord: https://discord.gg/mv3yErfpvq
 
 
 First steps
@@ -126,7 +130,6 @@ Built-in services
    topics/stats
    topics/email
    topics/telnetconsole
-   topics/webservice
 
 :doc:`topics/logging`
     Learn how to use Python's builtin logging on Scrapy.
@@ -140,9 +143,6 @@ Built-in services
 :doc:`topics/telnetconsole`
     Inspect a running crawler using a built-in Python console.
 
-:doc:`topics/webservice`
-    Monitor and control a crawler using a web service.
-
 
 Solving specific problems
 =========================
@@ -222,17 +222,23 @@ Extending Scrapy
    :hidden:
 
    topics/architecture
+   topics/addons
    topics/downloader-middleware
    topics/spider-middleware
    topics/extensions
-   topics/api
    topics/signals
+   topics/scheduler
    topics/exporters
+   topics/components
+   topics/api
 
 
 :doc:`topics/architecture`
     Understand the Scrapy architecture.
 
+:doc:`topics/addons`
+    Enable and configure third-party extensions.
+
 :doc:`topics/downloader-middleware`
     Customize how pages get requested and downloaded.
 
@@ -242,15 +248,22 @@ Extending Scrapy
 :doc:`topics/extensions`
     Extend Scrapy with your custom functionality
 
-:doc:`topics/api`
-    Use it on extensions and middlewares to extend Scrapy functionality
-
 :doc:`topics/signals`
     See all available signals and how to work with them.
 
+:doc:`topics/scheduler`
+    Understand the scheduler component.
+
 :doc:`topics/exporters`
     Quickly export your scraped items to a file (XML, CSV, etc).
 
+:doc:`topics/components`
+    Learn the common API and some good practices when building custom Scrapy
+    components.
+
+:doc:`topics/api`
+    Use it on extensions and middlewares to extend Scrapy functionality.
+
 
 All the rest
 ============

docs/intro/examples.rst

@@ -7,7 +7,7 @@ Examples
 The best way to learn is with examples, and Scrapy is no exception. For this
 reason, there is an example Scrapy project named quotesbot_, that you can use to
 play and learn more about Scrapy. It contains two spiders for
-http://quotes.toscrape.com, one using CSS selectors and another one using XPath
+https://quotes.toscrape.com, one using CSS selectors and another one using XPath
 expressions.
 
 The quotesbot_ project is available at: https://github.com/scrapy/quotesbot.

docs/intro/install.rst

@@ -9,9 +9,10 @@ Installation guide
 Supported Python versions
 =========================
 
-Scrapy requires Python 3.6+, either the CPython implementation (default) or
-the PyPy 7.2.0+ implementation (see :ref:`python:implementations`).
+Scrapy requires Python 3.8+, either the CPython implementation (default) or
+the PyPy implementation (see :ref:`python:implementations`).
 
+.. _intro-install-scrapy:
 
 Installing Scrapy
 =================
@@ -29,13 +30,13 @@ you can install Scrapy and its dependencies from PyPI with::
 
     pip install Scrapy
 
+We strongly recommend that you install Scrapy in :ref:`a dedicated virtualenv <intro-using-virtualenv>`,
+to avoid conflicting with your system packages.
+
 Note that sometimes this may require solving compilation issues for some Scrapy
 dependencies depending on your operating system, so be sure to check the
 :ref:`intro-install-platform-notes`.
 
-We strongly recommend that you install Scrapy in :ref:`a dedicated virtualenv <intro-using-virtualenv>`,
-to avoid conflicting with your system packages.
-
 For more detailed and platform specifics instructions, as well as
 troubleshooting information, read on.
 
@@ -51,17 +52,7 @@ Scrapy is written in pure Python and depends on a few key Python packages (among
 * `twisted`_, an asynchronous networking framework
 * `cryptography`_ and `pyOpenSSL`_, to deal with various network-level security needs
 
-The minimal versions which Scrapy is tested against are:
-
-* Twisted 14.0
-* lxml 3.4
-* pyOpenSSL 0.14
-
-Scrapy may work with older versions of these packages
-but it is not guaranteed it will continue working
-because it’s not being tested against them.
-
-Some of these packages themselves depends on non-Python packages
+Some of these packages themselves depend on non-Python packages
 that might require additional installation steps depending on your platform.
 Please check :ref:`platform-specific guides below <intro-install-platform-notes>`.
 
@@ -69,10 +60,9 @@ In case of any trouble related to these dependencies,
 please refer to their respective installation instructions:
 
 * `lxml installation`_
-* `cryptography installation`_
+* :doc:`cryptography installation <cryptography:installation>`
 
 .. _lxml installation: https://lxml.de/installation.html
-.. _cryptography installation: https://cryptography.io/en/latest/installation/
 
 
 .. _intro-using-virtualenv:
@@ -118,6 +108,27 @@ Once you've installed `Anaconda`_ or `Miniconda`_, install Scrapy with::
 
   conda install -c conda-forge scrapy
 
+To install Scrapy on Windows using ``pip``:
+
+.. warning::
+    This installation method requires “Microsoft Visual C++” for installing some 
+    Scrapy dependencies, which demands significantly more disk space than Anaconda.
+
+#. Download and execute `Microsoft C++ Build Tools`_ to install the Visual Studio Installer.
+
+#. Run the Visual Studio Installer.
+
+#. Under the Workloads section, select **C++ build tools**.
+
+#. Check the installation details and make sure following packages are selected as optional components:
+
+    * **MSVC**  (e.g MSVC v142 - VS 2019 C++ x64/x86 build tools (v14.23) )
+    
+    * **Windows SDK**  (e.g Windows 10 SDK (10.0.18362.0))
+
+#. Install the Visual Studio Build Tools.
+
+Now, you should be able to :ref:`install Scrapy <intro-install-scrapy>` using ``pip``.
 
 .. _intro-install-ubuntu:
 
@@ -169,14 +180,14 @@ prevents ``pip`` from updating system packages. This has to be addressed to
 successfully install Scrapy and its dependencies. Here are some proposed
 solutions:
 
-* *(Recommended)* **Don't** use system python, install a new, updated version
+* *(Recommended)* **Don't** use system Python. Install a new, updated version
   that doesn't conflict with the rest of your system. Here's how to do it using
   the `homebrew`_ package manager:
 
   * Install `homebrew`_ following the instructions in https://brew.sh/
 
   * Update your ``PATH`` variable to state that homebrew packages should be
-    used before system packages (Change ``.bashrc`` to ``.zshrc`` accordantly
+    used before system packages (Change ``.bashrc`` to ``.zshrc`` accordingly
     if you're using `zsh`_ as default shell)::
 
       echo "export PATH=/usr/local/bin:/usr/local/sbin:$PATH" >> ~/.bashrc
@@ -208,13 +219,13 @@ After any of these workarounds you should be able to install Scrapy::
 PyPy
 ----
 
-We recommend using the latest PyPy version. The version tested is 5.9.0.
+We recommend using the latest PyPy version.
 For PyPy3, only Linux installation was tested.
 
 Most Scrapy dependencies now have binary wheels for CPython, but not for PyPy.
 This means that these dependencies will be built during installation.
-On macOS, you are likely to face an issue with building Cryptography dependency,
-solution to this problem is described
+On macOS, you are likely to face an issue with building the Cryptography
+dependency. The solution to this problem is described
 `here <https://github.com/pyca/cryptography/issues/2692#issuecomment-272773481>`_,
 that is to ``brew install openssl`` and then export the flags that this command
 recommends (only needed when installing Scrapy). Installing on Linux has no special
@@ -265,10 +276,10 @@ For details, see `Issue #2473 <https://github.com/scrapy/scrapy/issues/2473>`_.
 .. _cryptography: https://cryptography.io/en/latest/
 .. _pyOpenSSL: https://pypi.org/project/pyOpenSSL/
 .. _setuptools: https://pypi.python.org/pypi/setuptools
-.. _AUR Scrapy package: https://aur.archlinux.org/packages/scrapy/
 .. _homebrew: https://brew.sh/
 .. _zsh: https://www.zsh.org/
-.. _Scrapinghub: https://scrapinghub.com
 .. _Anaconda: https://docs.anaconda.com/anaconda/
 .. _Miniconda: https://docs.conda.io/projects/conda/en/latest/user-guide/install/index.html
+.. _Visual Studio: https://docs.microsoft.com/en-us/visualstudio/install/install-visual-studio
+.. _Microsoft C++ Build Tools: https://visualstudio.microsoft.com/visual-cpp-build-tools/
 .. _conda-forge: https://conda-forge.org/

docs/intro/overview.rst

@@ -4,7 +4,7 @@
 Scrapy at a glance
 ==================
 
-Scrapy is an application framework for crawling web sites and extracting
+Scrapy (/ˈskreɪpaɪ/) is an application framework for crawling web sites and extracting
 structured data which can be used for a wide range of useful applications, like
 data mining, information processing or historical archival.
 
@@ -20,22 +20,24 @@ In order to show you what Scrapy brings to the table, we'll walk you through an
 example of a Scrapy Spider using the simplest way to run a spider.
 
 Here's the code for a spider that scrapes famous quotes from website
-http://quotes.toscrape.com, following the pagination::
+https://quotes.toscrape.com, following the pagination:
+
+.. code-block:: python
 
     import scrapy
 
 
     class QuotesSpider(scrapy.Spider):
-        name = 'quotes'
+        name = "quotes"
         start_urls = [
-            'http://quotes.toscrape.com/tag/humor/',
+            "https://quotes.toscrape.com/tag/humor/",
         ]
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'author': quote.xpath('span/small/text()').get(),
-                    'text': quote.css('span.text::text').get(),
+                    "author": quote.xpath("span/small/text()").get(),
+                    "text": quote.css("span.text::text").get(),
                 }
 
             next_page = response.css('li.next a::attr("href")').get()
@@ -45,9 +47,9 @@ http://quotes.toscrape.com, following the pagination::
 Put this in a text file, name it to something like ``quotes_spider.py``
 and run the spider using the :command:`runspider` command::
 
-    scrapy runspider quotes_spider.py -o quotes.jl
+    scrapy runspider quotes_spider.py -o quotes.jsonl
 
-When this finishes you will have in the ``quotes.jl`` file a list of the
+When this finishes you will have in the ``quotes.jsonl`` file a list of the
 quotes in JSON Lines format, containing text and author, looking like this::
 
     {"author": "Jane Austen", "text": "\u201cThe person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.\u201d"}

docs/intro/tutorial.rst

@@ -7,7 +7,7 @@ Scrapy Tutorial
 In this tutorial, we'll assume that Scrapy is already installed on your system.
 If that's not the case, see :ref:`intro-install`.
 
-We are going to scrape `quotes.toscrape.com <http://quotes.toscrape.com/>`_, a website
+We are going to scrape `quotes.toscrape.com <https://quotes.toscrape.com/>`_, a website
 that lists quotes from famous authors.
 
 This tutorial will walk you through these tasks:
@@ -78,12 +78,16 @@ Our first Spider
 
 Spiders are classes that you define and that Scrapy uses to scrape information
 from a website (or a group of websites). They must subclass
-:class:`~scrapy.spiders.Spider` and define the initial requests to make,
+:class:`~scrapy.Spider` and define the initial requests to make,
 optionally how to follow links in the pages, and how to parse the downloaded
 page content to extract data.
 
 This is the code for our first Spider. Save it in a file named
-``quotes_spider.py`` under the ``tutorial/spiders`` directory in your project::
+``quotes_spider.py`` under the ``tutorial/spiders`` directory in your project:
+
+.. code-block:: python
+
+    from pathlib import Path
 
     import scrapy
 
@@ -93,40 +97,39 @@ This is the code for our first Spider. Save it in a file named
 
         def start_requests(self):
             urls = [
-                'http://quotes.toscrape.com/page/1/',
-                'http://quotes.toscrape.com/page/2/',
+                "https://quotes.toscrape.com/page/1/",
+                "https://quotes.toscrape.com/page/2/",
             ]
             for url in urls:
                 yield scrapy.Request(url=url, callback=self.parse)
 
         def parse(self, response):
             page = response.url.split("/")[-2]
-            filename = f'quotes-{page}.html'
-            with open(filename, 'wb') as f:
-                f.write(response.body)
-            self.log(f'Saved file {filename}')
+            filename = f"quotes-{page}.html"
+            Path(filename).write_bytes(response.body)
+            self.log(f"Saved file {filename}")
 
 
-As you can see, our Spider subclasses :class:`scrapy.Spider <scrapy.spiders.Spider>`
+As you can see, our Spider subclasses :class:`scrapy.Spider <scrapy.Spider>`
 and defines some attributes and methods:
 
-* :attr:`~scrapy.spiders.Spider.name`: identifies the Spider. It must be
+* :attr:`~scrapy.Spider.name`: identifies the Spider. It must be
   unique within a project, that is, you can't set the same name for different
   Spiders.
 
-* :meth:`~scrapy.spiders.Spider.start_requests`: must return an iterable of
+* :meth:`~scrapy.Spider.start_requests`: must return an iterable of
   Requests (you can return a list of requests or write a generator function)
   which the Spider will begin to crawl from. Subsequent requests will be
   generated successively from these initial requests.
 
-* :meth:`~scrapy.spiders.Spider.parse`: a method that will be called to handle
+* :meth:`~scrapy.Spider.parse`: a method that will be called to handle
   the response downloaded for each of the requests made. The response parameter
   is an instance of :class:`~scrapy.http.TextResponse` that holds
   the page content and has further helpful methods to handle it.
 
-  The :meth:`~scrapy.spiders.Spider.parse` method usually parses the response, extracting
+  The :meth:`~scrapy.Spider.parse` method usually parses the response, extracting
   the scraped data as dicts and also finding new URLs to
-  follow and creating new requests (:class:`~scrapy.http.Request`) from them.
+  follow and creating new requests (:class:`~scrapy.Request`) from them.
 
 How to run our spider
 ---------------------
@@ -143,9 +146,9 @@ similar to this::
     2016-12-16 21:24:05 [scrapy.core.engine] INFO: Spider opened
     2016-12-16 21:24:05 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
     2016-12-16 21:24:05 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
-    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (404) <GET http://quotes.toscrape.com/robots.txt> (referer: None)
-    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://quotes.toscrape.com/page/1/> (referer: None)
-    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://quotes.toscrape.com/page/2/> (referer: None)
+    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (404) <GET https://quotes.toscrape.com/robots.txt> (referer: None)
+    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://quotes.toscrape.com/page/1/> (referer: None)
+    2016-12-16 21:24:05 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://quotes.toscrape.com/page/2/> (referer: None)
     2016-12-16 21:24:05 [quotes] DEBUG: Saved file quotes-1.html
     2016-12-16 21:24:05 [quotes] DEBUG: Saved file quotes-2.html
     2016-12-16 21:24:05 [scrapy.core.engine] INFO: Closing spider (finished)
@@ -162,7 +165,7 @@ for the respective URLs, as our ``parse`` method instructs.
 What just happened under the hood?
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Scrapy schedules the :class:`scrapy.Request <scrapy.http.Request>` objects
+Scrapy schedules the :class:`scrapy.Request <scrapy.Request>` objects
 returned by the ``start_requests`` method of the Spider. Upon receiving a
 response for each one, it instantiates :class:`~scrapy.http.Response` objects
 and calls the callback method associated with the request (in this case, the
@@ -171,12 +174,16 @@ and calls the callback method associated with the request (in this case, the
 
 A shortcut to the start_requests method
 ---------------------------------------
-Instead of implementing a :meth:`~scrapy.spiders.Spider.start_requests` method
-that generates :class:`scrapy.Request <scrapy.http.Request>` objects from URLs,
-you can just define a :attr:`~scrapy.spiders.Spider.start_urls` class attribute
+Instead of implementing a :meth:`~scrapy.Spider.start_requests` method
+that generates :class:`scrapy.Request <scrapy.Request>` objects from URLs,
+you can just define a :attr:`~scrapy.Spider.start_urls` class attribute
 with a list of URLs. This list will then be used by the default implementation
-of :meth:`~scrapy.spiders.Spider.start_requests` to create the initial requests
-for your spider::
+of :meth:`~scrapy.Spider.start_requests` to create the initial requests
+for your spider.
+
+.. code-block:: python
+
+    from pathlib import Path
 
     import scrapy
 
@@ -184,19 +191,18 @@ for your spider::
     class QuotesSpider(scrapy.Spider):
         name = "quotes"
         start_urls = [
-            'http://quotes.toscrape.com/page/1/',
-            'http://quotes.toscrape.com/page/2/',
+            "https://quotes.toscrape.com/page/1/",
+            "https://quotes.toscrape.com/page/2/",
         ]
 
         def parse(self, response):
             page = response.url.split("/")[-2]
-            filename = f'quotes-{page}.html'
-            with open(filename, 'wb') as f:
-                f.write(response.body)
+            filename = f"quotes-{page}.html"
+            Path(filename).write_bytes(response.body)
 
-The :meth:`~scrapy.spiders.Spider.parse` method will be called to handle each
+The :meth:`~scrapy.Spider.parse` method will be called to handle each
 of the requests for those URLs, even though we haven't explicitly told Scrapy
-to do so. This happens because :meth:`~scrapy.spiders.Spider.parse` is Scrapy's
+to do so. This happens because :meth:`~scrapy.Spider.parse` is Scrapy's
 default callback method, which is called for requests without an explicitly
 assigned callback.
 
@@ -207,7 +213,7 @@ Extracting data
 The best way to learn how to extract data with Scrapy is trying selectors
 using the :ref:`Scrapy shell <topics-shell>`. Run::
 
-    scrapy shell 'http://quotes.toscrape.com/page/1/'
+    scrapy shell 'https://quotes.toscrape.com/page/1/'
 
 .. note::
 
@@ -217,18 +223,18 @@ using the :ref:`Scrapy shell <topics-shell>`. Run::
 
    On Windows, use double quotes instead::
 
-       scrapy shell "http://quotes.toscrape.com/page/1/"
+       scrapy shell "https://quotes.toscrape.com/page/1/"
 
 You will see something like::
 
     [ ... Scrapy log here ... ]
-    2016-09-19 12:09:27 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://quotes.toscrape.com/page/1/> (referer: None)
+    2016-09-19 12:09:27 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://quotes.toscrape.com/page/1/> (referer: None)
     [s] Available Scrapy objects:
     [s]   scrapy     scrapy module (contains scrapy.Request, scrapy.Selector, etc)
     [s]   crawler    <scrapy.crawler.Crawler object at 0x7fa91d888c90>
     [s]   item       {}
-    [s]   request    <GET http://quotes.toscrape.com/page/1/>
-    [s]   response   <200 http://quotes.toscrape.com/page/1/>
+    [s]   request    <GET https://quotes.toscrape.com/page/1/>
+    [s]   response   <200 https://quotes.toscrape.com/page/1/>
     [s]   settings   <scrapy.settings.Settings object at 0x7fa91d888c10>
     [s]   spider     <DefaultSpider 'default' at 0x7fa91c8af990>
     [s] Useful shortcuts:
@@ -241,45 +247,69 @@ object:
 
 .. invisible-code-block: python
 
-    response = load_response('http://quotes.toscrape.com/page/1/', 'quotes1.html')
+    response = load_response('https://quotes.toscrape.com/page/1/', 'quotes1.html')
 
->>> response.css('title')
-[<Selector xpath='descendant-or-self::title' data='<title>Quotes to Scrape</title>'>]
+.. code-block:: pycon
+
+    >>> response.css("title")
+    [<Selector query='descendant-or-self::title' data='<title>Quotes to Scrape</title>'>]
 
 The result of running ``response.css('title')`` is a list-like object called
 :class:`~scrapy.selector.SelectorList`, which represents a list of
-:class:`~scrapy.selector.Selector` objects that wrap around XML/HTML elements
+:class:`~scrapy.Selector` objects that wrap around XML/HTML elements
 and allow you to run further queries to fine-grain the selection or extract the
 data.
 
 To extract the text from the title above, you can do:
 
->>> response.css('title::text').getall()
-['Quotes to Scrape']
+.. code-block:: pycon
+
+    >>> response.css("title::text").getall()
+    ['Quotes to Scrape']
 
 There are two things to note here: one is that we've added ``::text`` to the
 CSS query, to mean we want to select only the text elements directly inside
 ``<title>`` element.  If we don't specify ``::text``, we'd get the full title
 element, including its tags:
 
->>> response.css('title').getall()
-['<title>Quotes to Scrape</title>']
+.. code-block:: pycon
+
+    >>> response.css("title").getall()
+    ['<title>Quotes to Scrape</title>']
 
 The other thing is that the result of calling ``.getall()`` is a list: it is
 possible that a selector returns more than one result, so we extract them all.
 When you know you just want the first result, as in this case, you can do:
 
->>> response.css('title::text').get()
-'Quotes to Scrape'
+.. code-block:: pycon
+
+    >>> response.css("title::text").get()
+    'Quotes to Scrape'
 
 As an alternative, you could've written:
 
->>> response.css('title::text')[0].get()
-'Quotes to Scrape'
+.. code-block:: pycon
 
-However, using ``.get()`` directly on a :class:`~scrapy.selector.SelectorList`
-instance avoids an ``IndexError`` and returns ``None`` when it doesn't
-find any element matching the selection.
+    >>> response.css("title::text")[0].get()
+    'Quotes to Scrape'
+
+Accessing an index on a :class:`~scrapy.selector.SelectorList` instance will 
+raise an :exc:`IndexError` exception if there are no results:
+
+.. code-block:: pycon
+
+    >>> response.css("noelement")[0].get()
+    Traceback (most recent call last):
+    ...
+    IndexError: list index out of range
+
+You might want to use ``.get()`` directly on the 
+:class:`~scrapy.selector.SelectorList` instance instead, which returns ``None`` 
+if there are no results:
+
+.. code-block:: pycon
+
+    >>> response.css("noelement").get()
 
 There's a lesson here: for most scraping code, you want it to be resilient to
 errors due to things not being found on a page, so that even if some parts fail
@@ -290,14 +320,16 @@ Besides the :meth:`~scrapy.selector.SelectorList.getall` and
 the :meth:`~scrapy.selector.SelectorList.re` method to extract using
 :doc:`regular expressions <library/re>`:
 
->>> response.css('title::text').re(r'Quotes.*')
-['Quotes to Scrape']
->>> response.css('title::text').re(r'Q\w+')
-['Quotes']
->>> response.css('title::text').re(r'(\w+) to (\w+)')
-['Quotes', 'Scrape']
+.. code-block:: pycon
 
-In order to find the proper CSS selectors to use, you might find useful opening
+    >>> response.css("title::text").re(r"Quotes.*")
+    ['Quotes to Scrape']
+    >>> response.css("title::text").re(r"Q\w+")
+    ['Quotes']
+    >>> response.css("title::text").re(r"(\w+) to (\w+)")
+    ['Quotes', 'Scrape']
+
+In order to find the proper CSS selectors to use, you might find it useful to open
 the response page from the shell in your web browser using ``view(response)``.
 You can use your browser's developer tools to inspect the HTML and come up
 with a selector (see :ref:`topics-developer-tools`).
@@ -313,10 +345,12 @@ XPath: a brief intro
 
 Besides `CSS`_, Scrapy selectors also support using `XPath`_ expressions:
 
->>> response.xpath('//title')
-[<Selector xpath='//title' data='<title>Quotes to Scrape</title>'>]
->>> response.xpath('//title/text()').get()
-'Quotes to Scrape'
+.. code-block:: pycon
+
+    >>> response.xpath("//title")
+    [<Selector query='//title' data='<title>Quotes to Scrape</title>'>]
+    >>> response.xpath("//title/text()").get()
+    'Quotes to Scrape'
 
 XPath expressions are very powerful, and are the foundation of Scrapy
 Selectors. In fact, CSS selectors are converted to XPath under-the-hood. You
@@ -345,7 +379,7 @@ Extracting quotes and authors
 Now that you know a bit about selection and extraction, let's complete our
 spider by writing the code to extract the quotes from the web page.
 
-Each quote in http://quotes.toscrape.com is represented by HTML elements that look
+Each quote in https://quotes.toscrape.com is represented by HTML elements that look
 like this:
 
 .. code-block:: html
@@ -369,37 +403,45 @@ like this:
 Let's open up scrapy shell and play a bit to find out how to extract the data
 we want::
 
-    $ scrapy shell 'http://quotes.toscrape.com'
+    scrapy shell 'https://quotes.toscrape.com'
 
 We get a list of selectors for the quote HTML elements with:
 
->>> response.css("div.quote")
-[<Selector xpath="descendant-or-self::div[@class and contains(concat(' ', normalize-space(@class), ' '), ' quote ')]" data='<div class="quote" itemscope itemtype...'>,
- <Selector xpath="descendant-or-self::div[@class and contains(concat(' ', normalize-space(@class), ' '), ' quote ')]" data='<div class="quote" itemscope itemtype...'>,
- ...]
+.. code-block:: pycon
+
+    >>> response.css("div.quote")
+    [<Selector query="descendant-or-self::div[@class and contains(concat(' ', normalize-space(@class), ' '), ' quote ')]" data='<div class="quote" itemscope itemtype...'>,
+    <Selector query="descendant-or-self::div[@class and contains(concat(' ', normalize-space(@class), ' '), ' quote ')]" data='<div class="quote" itemscope itemtype...'>,
+    ...]
 
 Each of the selectors returned by the query above allows us to run further
 queries over their sub-elements. Let's assign the first selector to a
 variable, so that we can run our CSS selectors directly on a particular quote:
 
->>> quote = response.css("div.quote")[0]
+.. code-block:: pycon
+
+    >>> quote = response.css("div.quote")[0]
 
 Now, let's extract ``text``, ``author`` and the ``tags`` from that quote
 using the ``quote`` object we just created:
 
->>> text = quote.css("span.text::text").get()
->>> text
-'“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”'
->>> author = quote.css("small.author::text").get()
->>> author
-'Albert Einstein'
+.. code-block:: pycon
+
+    >>> text = quote.css("span.text::text").get()
+    >>> text
+    '“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”'
+    >>> author = quote.css("small.author::text").get()
+    >>> author
+    'Albert Einstein'
 
 Given that the tags are a list of strings, we can use the ``.getall()`` method
 to get all of them:
 
->>> tags = quote.css("div.tags a.tag::text").getall()
->>> tags
-['change', 'deep-thoughts', 'thinking', 'world']
+.. code-block:: pycon
+
+    >>> tags = quote.css("div.tags a.tag::text").getall()
+    >>> tags
+    ['change', 'deep-thoughts', 'thinking', 'world']
 
 .. invisible-code-block: python
 
@@ -408,14 +450,17 @@ to get all of them:
 Having figured out how to extract each bit, we can now iterate over all the
 quotes elements and put them together into a Python dictionary:
 
->>> for quote in response.css("div.quote"):
-...     text = quote.css("span.text::text").get()
-...     author = quote.css("small.author::text").get()
-...     tags = quote.css("div.tags a.tag::text").getall()
-...     print(dict(text=text, author=author, tags=tags))
-{'text': '“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”', 'author': 'Albert Einstein', 'tags': ['change', 'deep-thoughts', 'thinking', 'world']}
-{'text': '“It is our choices, Harry, that show what we truly are, far more than our abilities.”', 'author': 'J.K. Rowling', 'tags': ['abilities', 'choices']}
-...
+.. code-block:: pycon
+
+    >>> for quote in response.css("div.quote"):
+    ...     text = quote.css("span.text::text").get()
+    ...     author = quote.css("small.author::text").get()
+    ...     tags = quote.css("div.tags a.tag::text").getall()
+    ...     print(dict(text=text, author=author, tags=tags))
+    ...
+    {'text': '“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”', 'author': 'Albert Einstein', 'tags': ['change', 'deep-thoughts', 'thinking', 'world']}
+    {'text': '“It is our choices, Harry, that show what we truly are, far more than our abilities.”', 'author': 'J.K. Rowling', 'tags': ['abilities', 'choices']}
+    ...
 
 Extracting data in our spider
 -----------------------------
@@ -426,7 +471,9 @@ extraction logic above into our spider.
 
 A Scrapy spider typically generates many dictionaries containing the data
 extracted from the page. To do that, we use the ``yield`` Python keyword
-in the callback, as you can see below::
+in the callback, as you can see below:
+
+.. code-block:: python
 
     import scrapy
 
@@ -434,23 +481,31 @@ in the callback, as you can see below::
     class QuotesSpider(scrapy.Spider):
         name = "quotes"
         start_urls = [
-            'http://quotes.toscrape.com/page/1/',
-            'http://quotes.toscrape.com/page/2/',
+            "https://quotes.toscrape.com/page/1/",
+            "https://quotes.toscrape.com/page/2/",
         ]
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'text': quote.css('span.text::text').get(),
-                    'author': quote.css('small.author::text').get(),
-                    'tags': quote.css('div.tags a.tag::text').getall(),
+                    "text": quote.css("span.text::text").get(),
+                    "author": quote.css("small.author::text").get(),
+                    "tags": quote.css("div.tags a.tag::text").getall(),
                 }
 
-If you run this spider, it will output the extracted data with the log::
+To run this spider, exit the scrapy shell by entering::
 
-    2016-09-19 18:57:19 [scrapy.core.scraper] DEBUG: Scraped from <200 http://quotes.toscrape.com/page/1/>
+    quit()
+
+Then, run::
+
+   scrapy crawl quotes
+
+Now, it should output the extracted data with the log::
+
+    2016-09-19 18:57:19 [scrapy.core.scraper] DEBUG: Scraped from <200 https://quotes.toscrape.com/page/1/>
     {'tags': ['life', 'love'], 'author': 'André Gide', 'text': '“It is better to be hated for what you are than to be loved for what you are not.”'}
-    2016-09-19 18:57:19 [scrapy.core.scraper] DEBUG: Scraped from <200 http://quotes.toscrape.com/page/1/>
+    2016-09-19 18:57:19 [scrapy.core.scraper] DEBUG: Scraped from <200 https://quotes.toscrape.com/page/1/>
     {'tags': ['edison', 'failure', 'inspirational', 'paraphrased'], 'author': 'Thomas A. Edison', 'text': "“I have not failed. I've just found 10,000 ways that won't work.”"}
 
 
@@ -464,7 +519,7 @@ The simplest way to store the scraped data is by using :ref:`Feed exports
 
     scrapy crawl quotes -O quotes.json
 
-That will generate an ``quotes.json`` file containing all scraped items,
+That will generate a ``quotes.json`` file containing all scraped items,
 serialized in `JSON`_.
 
 The ``-O`` command-line switch overwrites any existing file; use ``-o`` instead
@@ -472,13 +527,13 @@ to append new content to any existing file. However, appending to a JSON file
 makes the file contents invalid JSON. When appending to a file, consider
 using a different serialization format, such as `JSON Lines`_::
 
-    scrapy crawl quotes -o quotes.jl
+    scrapy crawl quotes -o quotes.jsonl
 
 The `JSON Lines`_ format is useful because it's stream-like, you can easily
 append new records to it. It doesn't have the same problem of JSON when you run
 twice. Also, as each record is a separate line, you can process big files
 without having to fit everything in memory, there are tools like `JQ`_ to help
-doing that at the command-line.
+do that at the command-line.
 
 In small projects (like the one in this tutorial), that should be enough.
 However, if you want to perform more complex things with the scraped items, you
@@ -495,7 +550,7 @@ Following links
 ===============
 
 Let's say, instead of just scraping the stuff from the first two pages
-from http://quotes.toscrape.com, you want quotes from all the pages in the website.
+from https://quotes.toscrape.com, you want quotes from all the pages in the website.
 
 Now that you know how to extract data from pages, let's see how to follow links
 from them.
@@ -521,17 +576,23 @@ This gets the anchor element, but we want the attribute ``href``. For that,
 Scrapy supports a CSS extension that lets you select the attribute contents,
 like this:
 
->>> response.css('li.next a::attr(href)').get()
-'/page/2/'
+.. code-block:: pycon
+
+    >>> response.css("li.next a::attr(href)").get()
+    '/page/2/'
 
 There is also an ``attrib`` property available
 (see :ref:`selecting-attributes` for more):
 
->>> response.css('li.next a').attrib['href']
-'/page/2/'
+.. code-block:: pycon
+
+    >>> response.css("li.next a").attrib["href"]
+    '/page/2/'
 
 Let's see now our spider modified to recursively follow the link to the next
-page, extracting data from it::
+page, extracting data from it:
+
+.. code-block:: python
 
     import scrapy
 
@@ -539,18 +600,18 @@ page, extracting data from it::
     class QuotesSpider(scrapy.Spider):
         name = "quotes"
         start_urls = [
-            'http://quotes.toscrape.com/page/1/',
+            "https://quotes.toscrape.com/page/1/",
         ]
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'text': quote.css('span.text::text').get(),
-                    'author': quote.css('small.author::text').get(),
-                    'tags': quote.css('div.tags a.tag::text').getall(),
+                    "text": quote.css("span.text::text").get(),
+                    "author": quote.css("small.author::text").get(),
+                    "tags": quote.css("div.tags a.tag::text").getall(),
                 }
 
-            next_page = response.css('li.next a::attr(href)').get()
+            next_page = response.css("li.next a::attr(href)").get()
             if next_page is not None:
                 next_page = response.urljoin(next_page)
                 yield scrapy.Request(next_page, callback=self.parse)
@@ -582,7 +643,9 @@ A shortcut for creating Requests
 --------------------------------
 
 As a shortcut for creating Request objects you can use
-:meth:`response.follow <scrapy.http.TextResponse.follow>`::
+:meth:`response.follow <scrapy.http.TextResponse.follow>`:
+
+.. code-block:: python
 
     import scrapy
 
@@ -590,18 +653,18 @@ As a shortcut for creating Request objects you can use
     class QuotesSpider(scrapy.Spider):
         name = "quotes"
         start_urls = [
-            'http://quotes.toscrape.com/page/1/',
+            "https://quotes.toscrape.com/page/1/",
         ]
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'text': quote.css('span.text::text').get(),
-                    'author': quote.css('span small::text').get(),
-                    'tags': quote.css('div.tags a.tag::text').getall(),
+                    "text": quote.css("span.text::text").get(),
+                    "author": quote.css("span small::text").get(),
+                    "tags": quote.css("div.tags a.tag::text").getall(),
                 }
 
-            next_page = response.css('li.next a::attr(href)').get()
+            next_page = response.css("li.next a::attr(href)").get()
             if next_page is not None:
                 yield response.follow(next_page, callback=self.parse)
 
@@ -609,58 +672,72 @@ Unlike scrapy.Request, ``response.follow`` supports relative URLs directly - no
 need to call urljoin. Note that ``response.follow`` just returns a Request
 instance; you still have to yield this Request.
 
-You can also pass a selector to ``response.follow`` instead of a string;
-this selector should extract necessary attributes::
+.. skip: start
 
-    for href in response.css('ul.pager a::attr(href)'):
+You can also pass a selector to ``response.follow`` instead of a string;
+this selector should extract necessary attributes:
+
+.. code-block:: python
+
+    for href in response.css("ul.pager a::attr(href)"):
         yield response.follow(href, callback=self.parse)
 
 For ``<a>`` elements there is a shortcut: ``response.follow`` uses their href
-attribute automatically. So the code can be shortened further::
+attribute automatically. So the code can be shortened further:
 
-    for a in response.css('ul.pager a'):
+.. code-block:: python
+
+    for a in response.css("ul.pager a"):
         yield response.follow(a, callback=self.parse)
 
 To create multiple requests from an iterable, you can use
-:meth:`response.follow_all <scrapy.http.TextResponse.follow_all>` instead::
+:meth:`response.follow_all <scrapy.http.TextResponse.follow_all>` instead:
 
-    anchors = response.css('ul.pager a')
+.. code-block:: python
+
+    anchors = response.css("ul.pager a")
     yield from response.follow_all(anchors, callback=self.parse)
 
-or, shortening it further::
+or, shortening it further:
 
-    yield from response.follow_all(css='ul.pager a', callback=self.parse)
+.. code-block:: python
+
+    yield from response.follow_all(css="ul.pager a", callback=self.parse)
+
+.. skip: end
 
 
 More examples and patterns
 --------------------------
 
 Here is another spider that illustrates callbacks and following links,
-this time for scraping author information::
+this time for scraping author information:
+
+.. code-block:: python
 
     import scrapy
 
 
     class AuthorSpider(scrapy.Spider):
-        name = 'author'
+        name = "author"
 
-        start_urls = ['http://quotes.toscrape.com/']
+        start_urls = ["https://quotes.toscrape.com/"]
 
         def parse(self, response):
-            author_page_links = response.css('.author + a')
+            author_page_links = response.css(".author + a")
             yield from response.follow_all(author_page_links, self.parse_author)
 
-            pagination_links = response.css('li.next a')
+            pagination_links = response.css("li.next a")
             yield from response.follow_all(pagination_links, self.parse)
 
         def parse_author(self, response):
             def extract_with_css(query):
-                return response.css(query).get(default='').strip()
+                return response.css(query).get(default="").strip()
 
             yield {
-                'name': extract_with_css('h3.author-title::text'),
-                'birthdate': extract_with_css('.author-born-date::text'),
-                'bio': extract_with_css('.author-description::text'),
+                "name": extract_with_css("h3.author-title::text"),
+                "birthdate": extract_with_css(".author-born-date::text"),
+                "bio": extract_with_css(".author-description::text"),
             }
 
 This spider will start from the main page, it will follow all the links to the
@@ -670,7 +747,7 @@ the pagination links with the ``parse`` callback as we saw before.
 Here we're passing callbacks to
 :meth:`response.follow_all <scrapy.http.TextResponse.follow_all>` as positional
 arguments to make the code shorter; it also works for
-:class:`~scrapy.http.Request`.
+:class:`~scrapy.Request`.
 
 The ``parse_author`` callback defines a helper function to extract and cleanup the
 data from a CSS query and yields the Python dict with the author data.
@@ -708,7 +785,9 @@ spider attributes by default.
 
 In this example, the value provided for the ``tag`` argument will be available
 via ``self.tag``. You can use this to make your spider fetch only quotes
-with a specific tag, building the URL based on the argument::
+with a specific tag, building the URL based on the argument:
+
+.. code-block:: python
 
     import scrapy
 
@@ -717,27 +796,27 @@ with a specific tag, building the URL based on the argument::
         name = "quotes"
 
         def start_requests(self):
-            url = 'http://quotes.toscrape.com/'
-            tag = getattr(self, 'tag', None)
+            url = "https://quotes.toscrape.com/"
+            tag = getattr(self, "tag", None)
             if tag is not None:
-                url = url + 'tag/' + tag
+                url = url + "tag/" + tag
             yield scrapy.Request(url, self.parse)
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'text': quote.css('span.text::text').get(),
-                    'author': quote.css('small.author::text').get(),
+                    "text": quote.css("span.text::text").get(),
+                    "author": quote.css("small.author::text").get(),
                 }
 
-            next_page = response.css('li.next a::attr(href)').get()
+            next_page = response.css("li.next a::attr(href)").get()
             if next_page is not None:
                 yield response.follow(next_page, self.parse)
 
 
 If you pass the ``tag=humor`` argument to this spider, you'll notice that it
 will only visit URLs from the ``humor`` tag, such as
-``http://quotes.toscrape.com/tag/humor``.
+``https://quotes.toscrape.com/tag/humor``.
 
 You can :ref:`learn more about handling spider arguments here <spiderargs>`.
 

docs/requirements.txt

@@ -1,4 +1,4 @@
-Sphinx>=3.0
-sphinx-hoverxref>=0.2b1
-sphinx-notfound-page>=0.4
-sphinx_rtd_theme>=0.4
+sphinx==5.0.2
+sphinx-hoverxref==1.1.1
+sphinx-notfound-page==0.8
+sphinx-rtd-theme==1.0.0

docs/topics/addons.rst

@@ -0,0 +1,193 @@
+.. _topics-addons:
+
+=======
+Add-ons
+=======
+
+Scrapy's add-on system is a framework which unifies managing and configuring
+components that extend Scrapy's core functionality, such as middlewares,
+extensions, or pipelines. It provides users with a plug-and-play experience in
+Scrapy extension management, and grants extensive configuration control to
+developers.
+
+
+Activating and configuring add-ons
+==================================
+
+During :class:`~scrapy.crawler.Crawler` initialization, the list of enabled
+add-ons is read from your ``ADDONS`` setting.
+
+The ``ADDONS`` setting is a dict in which every key is an add-on class or its
+import path and the value is its priority.
+
+This is an example where two add-ons are enabled in a project's
+``settings.py``::
+
+    ADDONS = {
+        'path.to.someaddon': 0,
+        SomeAddonClass: 1,
+    }
+
+
+Writing your own add-ons
+========================
+
+Add-ons are Python classes that include the following method:
+
+.. method:: update_settings(settings)
+
+    This method is called during the initialization of the
+    :class:`~scrapy.crawler.Crawler`. Here, you should perform dependency checks
+    (e.g. for external Python libraries) and update the
+    :class:`~scrapy.settings.Settings` object as wished, e.g. enable components
+    for this add-on or set required configuration of other extensions.
+
+    :param settings: The settings object storing Scrapy/component configuration
+    :type settings: :class:`~scrapy.settings.Settings`
+
+They can also have the following method:
+
+.. classmethod:: from_crawler(cls, crawler)
+   :noindex:
+
+   If present, this class method is called to create an add-on instance
+   from a :class:`~scrapy.crawler.Crawler`. It must return a new instance
+   of the add-on. The crawler object provides access to all Scrapy core
+   components like settings and signals; it is a way for the add-on to access
+   them and hook its functionality into Scrapy.
+
+   :param crawler: The crawler that uses this add-on
+   :type crawler: :class:`~scrapy.crawler.Crawler`
+
+The settings set by the add-on should use the ``addon`` priority (see
+:ref:`populating-settings` and :func:`scrapy.settings.BaseSettings.set`)::
+
+    class MyAddon:
+        def update_settings(self, settings):
+            settings.set("DNSCACHE_ENABLED", True, "addon")
+
+This allows users to override these settings in the project or spider
+configuration. This is not possible with settings that are mutable objects,
+such as the dict that is a value of :setting:`ITEM_PIPELINES`. In these cases
+you can provide an add-on-specific setting that governs whether the add-on will
+modify :setting:`ITEM_PIPELINES`::
+
+    class MyAddon:
+        def update_settings(self, settings):
+            if settings.getbool("MYADDON_ENABLE_PIPELINE"):
+                settings["ITEM_PIPELINES"]["path.to.mypipeline"] = 200
+
+If the ``update_settings`` method raises
+:exc:`scrapy.exceptions.NotConfigured`, the add-on will be skipped. This makes
+it easy to enable an add-on only when some conditions are met.
+
+Fallbacks
+---------
+
+Some components provided by add-ons need to fall back to "default"
+implementations, e.g. a custom download handler needs to send the request that
+it doesn't handle via the default download handler, or a stats collector that
+includes some additional processing but otherwise uses the default stats
+collector. And it's possible that a project needs to use several custom
+components of the same type, e.g. two custom download handlers that support
+different kinds of custom requests and still need to use the default download
+handler for other requests. To make such use cases easier to configure, we
+recommend that such custom components should be written in the following way:
+
+1. The custom component (e.g. ``MyDownloadHandler``) shouldn't inherit from the
+   default Scrapy one (e.g.
+   ``scrapy.core.downloader.handlers.http.HTTPDownloadHandler``), but instead
+   be able to load the class of the fallback component from a special setting
+   (e.g. ``MY_FALLBACK_DOWNLOAD_HANDLER``), create an instance of it and use
+   it.
+2. The add-ons that include these components should read the current value of
+   the default setting (e.g. ``DOWNLOAD_HANDLERS``) in their
+   ``update_settings()`` methods, save that value into the fallback setting
+   (``MY_FALLBACK_DOWNLOAD_HANDLER`` mentioned earlier) and set the default
+   setting to the component provided by the add-on (e.g.
+   ``MyDownloadHandler``). If the fallback setting is already set by the user,
+   they shouldn't change it.
+3. This way, if there are several add-ons that want to modify the same setting,
+   all of them will fallback to the component from the previous one and then to
+   the Scrapy default. The order of that depends on the priority order in the
+   ``ADDONS`` setting.
+
+
+Add-on examples
+===============
+
+Set some basic configuration:
+
+.. code-block:: python
+
+    class MyAddon:
+        def update_settings(self, settings):
+            settings["ITEM_PIPELINES"]["path.to.mypipeline"] = 200
+            settings.set("DNSCACHE_ENABLED", True, "addon")
+
+Check dependencies:
+
+.. code-block:: python
+
+    class MyAddon:
+        def update_settings(self, settings):
+            try:
+                import boto
+            except ImportError:
+                raise NotConfigured("MyAddon requires the boto library")
+            ...
+
+Access the crawler instance:
+
+.. code-block:: python
+
+    class MyAddon:
+        def __init__(self, crawler) -> None:
+            super().__init__()
+            self.crawler = crawler
+
+        @classmethod
+        def from_crawler(cls, crawler):
+            return cls(crawler)
+
+        def update_settings(self, settings):
+            ...
+
+Use a fallback component:
+
+.. code-block:: python
+
+    from scrapy.core.downloader.handlers.http import HTTPDownloadHandler
+
+
+    FALLBACK_SETTING = "MY_FALLBACK_DOWNLOAD_HANDLER"
+
+
+    class MyHandler:
+        lazy = False
+
+        def __init__(self, settings, crawler):
+            dhcls = load_object(settings.get(FALLBACK_SETTING))
+            self._fallback_handler = create_instance(
+                dhcls,
+                settings=None,
+                crawler=crawler,
+            )
+
+        def download_request(self, request, spider):
+            if request.meta.get("my_params"):
+                # handle the request
+                ...
+            else:
+                return self._fallback_handler.download_request(request, spider)
+
+
+    class MyAddon:
+        def update_settings(self, settings):
+            if not settings.get(FALLBACK_SETTING):
+                settings.set(
+                    FALLBACK_SETTING,
+                    settings.getwithbase("DOWNLOAD_HANDLERS")["https"],
+                    "addon",
+                )
+            settings["DOWNLOAD_HANDLERS"]["https"] = MyHandler

docs/topics/api.rst

@@ -29,9 +29,16 @@ how you :ref:`configure the downloader middlewares
 .. class:: Crawler(spidercls, settings)
 
     The Crawler object must be instantiated with a
-    :class:`scrapy.spiders.Spider` subclass and a
+    :class:`scrapy.Spider` subclass and a
     :class:`scrapy.settings.Settings` object.
 
+    .. attribute:: request_fingerprinter
+
+        The request fingerprint builder of this crawler.
+
+        This is used from extensions and middlewares to build short, unique
+        identifiers for requests. See :ref:`request-fingerprints`.
+
     .. attribute:: settings
 
         The settings manager of this crawler.
@@ -93,7 +100,7 @@ how you :ref:`configure the downloader middlewares
 
         Starts the crawler by instantiating its spider class with the given
         ``args`` and ``kwargs`` arguments, while setting the execution engine in
-        motion.
+        motion. Should be called only once.
 
         Returns a deferred that is fired when the crawl is finished.
 
@@ -125,16 +132,15 @@ Settings API
     precedence over lesser ones when setting and retrieving values in the
     :class:`~scrapy.settings.Settings` class.
 
-    .. highlight:: python
-
-    ::
+    .. code-block:: python
 
         SETTINGS_PRIORITIES = {
-            'default': 0,
-            'command': 10,
-            'project': 20,
-            'spider': 30,
-            'cmdline': 40,
+            "default": 0,
+            "command": 10,
+            "addon": 15,
+            "project": 20,
+            "spider": 30,
+            "cmdline": 40,
         }
 
     For a detailed explanation on each settings sources, see:
@@ -196,7 +202,7 @@ SpiderLoader API
        match the request's url against the domains of the spiders.
 
        :param request: queried request
-       :type request: :class:`~scrapy.http.Request` instance
+       :type request: :class:`~scrapy.Request` instance
 
 .. _topics-api-signals:
 

docs/topics/architecture.rst

@@ -67,7 +67,7 @@ this:
    the :ref:`Scheduler <component-scheduler>` and asks for possible next Requests
    to crawl.
 
-9. The process repeats (from step 1) until there are no more requests from the
+9. The process repeats (from step 3) until there are no more requests from the
    :ref:`Scheduler <component-scheduler>`.
 
 Components
@@ -87,8 +87,9 @@ of the system, and triggering events when certain actions occur. See the
 Scheduler
 ---------
 
-The Scheduler receives requests from the engine and enqueues them for feeding
-them later (also to the engine) when the engine requests them.
+The :ref:`scheduler <topics-scheduler>` receives requests from the engine and 
+enqueues them for feeding them later (also to the engine) when the engine 
+requests them.
 
 .. _component-downloader:
 

docs/topics/asyncio.rst

@@ -1,16 +1,15 @@
+.. _using-asyncio:
+
 =======
 asyncio
 =======
 
 .. versionadded:: 2.0
 
-Scrapy has partial support :mod:`asyncio`. After you :ref:`install the asyncio
-reactor <install-asyncio>`, you may use :mod:`asyncio` and
+Scrapy has partial support for :mod:`asyncio`. After you :ref:`install the
+asyncio reactor <install-asyncio>`, you may use :mod:`asyncio` and
 :mod:`asyncio`-powered libraries in any :doc:`coroutine <coroutines>`.
 
-.. warning:: :mod:`asyncio` support in Scrapy is experimental. Future Scrapy
-             versions may introduce related changes without a deprecation
-             period or warning.
 
 .. _install-asyncio:
 
@@ -27,14 +26,121 @@ reactor manually. You can do that using
 
     install_reactor('twisted.internet.asyncioreactor.AsyncioSelectorReactor')
 
+
+.. _asyncio-preinstalled-reactor:
+
+Handling a pre-installed reactor
+================================
+
+``twisted.internet.reactor`` and some other Twisted imports install the default
+Twisted reactor as a side effect. Once a Twisted reactor is installed, it is
+not possible to switch to a different reactor at run time.
+
+If you :ref:`configure the asyncio Twisted reactor <install-asyncio>` and, at
+run time, Scrapy complains that a different reactor is already installed,
+chances are you have some such imports in your code.
+
+You can usually fix the issue by moving those offending module-level Twisted
+imports to the method or function definitions where they are used. For example,
+if you have something like:
+
+.. code-block:: python
+
+    from twisted.internet import reactor
+
+
+    def my_function():
+        reactor.callLater(...)
+
+Switch to something like:
+
+.. code-block:: python
+
+    def my_function():
+        from twisted.internet import reactor
+
+        reactor.callLater(...)
+
+Alternatively, you can try to :ref:`manually install the asyncio reactor
+<install-asyncio>`, with :func:`~scrapy.utils.reactor.install_reactor`, before
+those imports happen.
+
+
+.. _asyncio-await-dfd:
+
+Awaiting on Deferreds
+=====================
+
+When the asyncio reactor isn't installed, you can await on Deferreds in the
+coroutines directly. When it is installed, this is not possible anymore, due to
+specifics of the Scrapy coroutine integration (the coroutines are wrapped into
+:class:`asyncio.Future` objects, not into
+:class:`~twisted.internet.defer.Deferred` directly), and you need to wrap them into
+Futures. Scrapy provides two helpers for this:
+
+.. autofunction:: scrapy.utils.defer.deferred_to_future
+.. autofunction:: scrapy.utils.defer.maybe_deferred_to_future
+.. tip:: If you need to use these functions in code that aims to be compatible
+         with lower versions of Scrapy that do not provide these functions,
+         down to Scrapy 2.0 (earlier versions do not support
+         :mod:`asyncio`), you can copy the implementation of these functions
+         into your own code.
+
+
+.. _enforce-asyncio-requirement:
+
+Enforcing asyncio as a requirement
+==================================
+
+If you are writing a :ref:`component <topics-components>` that requires asyncio
+to work, use :func:`scrapy.utils.reactor.is_asyncio_reactor_installed` to
+:ref:`enforce it as a requirement <enforce-component-requirements>`. For
+example:
+
+.. code-block:: python
+
+    from scrapy.utils.reactor import is_asyncio_reactor_installed
+
+
+    class MyComponent:
+        def __init__(self):
+            if not is_asyncio_reactor_installed():
+                raise ValueError(
+                    f"{MyComponent.__qualname__} requires the asyncio Twisted "
+                    f"reactor. Make sure you have it configured in the "
+                    f"TWISTED_REACTOR setting. See the asyncio documentation "
+                    f"of Scrapy for more information."
+                )
+
+
+.. _asyncio-windows:
+
+Windows-specific notes
+======================
+
+The Windows implementation of :mod:`asyncio` can use two event loop
+implementations, :class:`~asyncio.ProactorEventLoop` (default) and
+:class:`~asyncio.SelectorEventLoop`. However, only
+:class:`~asyncio.SelectorEventLoop` works with Twisted.
+
+Scrapy changes the event loop class to :class:`~asyncio.SelectorEventLoop`
+automatically when you change the :setting:`TWISTED_REACTOR` setting or call
+:func:`~scrapy.utils.reactor.install_reactor`.
+
+.. note:: Other libraries you use may require
+          :class:`~asyncio.ProactorEventLoop`, e.g. because it supports
+          subprocesses (this is the case with `playwright`_), so you cannot use
+          them together with Scrapy on Windows (but you should be able to use
+          them on WSL or native Linux).
+
+.. _playwright: https://github.com/microsoft/playwright-python
+
+
 .. _using-custom-loops:
 
 Using custom asyncio loops
-==========================    
+==========================
 
 You can also use custom asyncio event loops with the asyncio reactor. Set the
-:setting:`ASYNCIO_EVENT_LOOP` setting to the import path of the desired event loop class to
-use it instead of the default asyncio event loop.
-
-
-
+:setting:`ASYNCIO_EVENT_LOOP` setting to the import path of the desired event
+loop class to use it instead of the default asyncio event loop.

docs/topics/benchmarking.rst

@@ -81,5 +81,6 @@ follow links, any custom spider you write will probably do more stuff which
 results in slower crawl rates. How slower depends on how much your spider does
 and how well it's written.
 
-In the future, more cases will be added to the benchmarking suite to cover
-other common scenarios.
+Use scrapy-bench_ for more complex benchmarking.
+
+.. _scrapy-bench: https://github.com/scrapy/scrapy-bench

docs/topics/broad-crawls.rst

@@ -48,9 +48,11 @@ Scrapy’s default scheduler priority queue is ``'scrapy.pqueues.ScrapyPriorityQ
 It works best during single-domain crawl. It does not work well with crawling
 many different domains in parallel
 
-To apply the recommended priority queue use::
+To apply the recommended priority queue use:
 
-    SCHEDULER_PRIORITY_QUEUE = 'scrapy.pqueues.DownloaderAwarePriorityQueue'
+.. code-block:: python
+
+    SCHEDULER_PRIORITY_QUEUE = "scrapy.pqueues.DownloaderAwarePriorityQueue"
 
 .. _broad-crawls-concurrency:
 
@@ -68,10 +70,12 @@ IP (:setting:`CONCURRENT_REQUESTS_PER_IP`).
 
 The default global concurrency limit in Scrapy is not suitable for crawling
 many different domains in parallel, so you will want to increase it. How much
-to increase it will depend on how much CPU and memory you crawler will have
+to increase it will depend on how much CPU and memory your crawler will have
 available.
 
-A good starting point is ``100``::
+A good starting point is ``100``:
+
+.. code-block:: python
 
     CONCURRENT_REQUESTS = 100
 
@@ -92,7 +96,9 @@ hitting DNS resolver timeouts. Possible solution to increase the number of
 threads handling DNS queries. The DNS queue will be processed faster speeding
 up establishing of connection and crawling overall.
 
-To increase maximum thread pool size use::
+To increase maximum thread pool size use:
+
+.. code-block:: python
 
     REACTOR_THREADPOOL_MAXSIZE = 20
 
@@ -114,9 +120,11 @@ should not use ``DEBUG`` log level when preforming large broad crawls in
 production. Using ``DEBUG`` level when developing your (broad) crawler may be
 fine though.
 
-To set the log level use::
+To set the log level use:
 
-    LOG_LEVEL = 'INFO'
+.. code-block:: python
+
+    LOG_LEVEL = "INFO"
 
 Disable cookies
 ===============
@@ -126,7 +134,9 @@ doing broad crawls (search engine crawlers ignore them), and they improve
 performance by saving some CPU cycles and reducing the memory footprint of your
 Scrapy crawler.
 
-To disable cookies use::
+To disable cookies use:
+
+.. code-block:: python
 
     COOKIES_ENABLED = False
 
@@ -138,7 +148,9 @@ when sites causes are very slow (or fail) to respond, thus causing a timeout
 error which gets retried many times, unnecessarily, preventing crawler capacity
 to be reused for other domains.
 
-To disable retries use::
+To disable retries use:
+
+.. code-block:: python
 
     RETRY_ENABLED = False
 
@@ -149,7 +161,9 @@ Unless you are crawling from a very slow connection (which shouldn't be the
 case for broad crawls) reduce the download timeout so that stuck requests are
 discarded quickly and free up capacity to process the next ones.
 
-To reduce the download timeout use::
+To reduce the download timeout use:
+
+.. code-block:: python
 
     DOWNLOAD_TIMEOUT = 15
 
@@ -162,7 +176,9 @@ revisiting the site at a later crawl. This also help to keep the number of
 request constant per crawl batch, otherwise redirect loops may cause the
 crawler to dedicate too many resources on any specific domain.
 
-To disable redirects use::
+To disable redirects use:
+
+.. code-block:: python
 
     REDIRECT_ENABLED = False
 
@@ -179,7 +195,9 @@ Pages can indicate it in two ways:
    "main", "index" website pages.
 
 Scrapy handles (1) automatically; to handle (2) enable
-:ref:`AjaxCrawlMiddleware <ajaxcrawl-middleware>`::
+:ref:`AjaxCrawlMiddleware <ajaxcrawl-middleware>`:
+
+.. code-block:: python
 
     AJAXCRAWL_ENABLED = True
 

docs/topics/commands.rst

@@ -230,10 +230,13 @@ Usage example::
 genspider
 ---------
 
-* Syntax: ``scrapy genspider [-t template] <name> <domain>``
+* Syntax: ``scrapy genspider [-t template] <name> <domain or URL>``
 * Requires project: *no*
 
-Create a new spider in the current folder or in the current project's ``spiders`` folder, if called from inside a project. The ``<name>`` parameter is set as the spider's ``name``, while ``<domain>`` is used to generate the ``allowed_domains`` and ``start_urls`` spider's attributes.
+.. versionadded:: 2.6.0
+   The ability to pass a URL instead of a domain.
+
+Create a new spider in the current folder or in the current project's ``spiders`` folder, if called from inside a project. The ``<name>`` parameter is set as the spider's ``name``, while ``<domain or URL>`` is used to generate the ``allowed_domains`` and ``start_urls`` spider's attributes.
 
 Usage example::
 
@@ -265,11 +268,31 @@ crawl
 
 Start crawling using a spider.
 
+Supported options:
+
+* ``-h, --help``: show a help message and exit
+
+* ``-a NAME=VALUE``: set a spider argument (may be repeated)
+
+* ``--output FILE`` or ``-o FILE``: append scraped items to the end of FILE (use - for stdout), to define format set a colon at the end of the output URI (i.e. ``-o FILE:FORMAT``)
+
+* ``--overwrite-output FILE`` or ``-O FILE``: dump scraped items into FILE, overwriting any existing file, to define format set a colon at the end of the output URI (i.e. ``-O FILE:FORMAT``)
+
+* ``--output-format FORMAT`` or ``-t FORMAT``: deprecated way to define format to use for dumping items, does not work in combination with ``-O``
+
 Usage examples::
 
     $ scrapy crawl myspider
     [ ... myspider starts crawling ... ]
 
+    $ scrapy crawl -o myfile:csv myspider
+    [ ... myspider starts crawling and appends the result to the file myfile in csv format ... ]
+
+    $ scrapy crawl -O myfile:json myspider
+    [ ... myspider starts crawling and saves the result in myfile in json format overwriting the original content... ]
+
+    $ scrapy crawl -o myfile -t csv myspider
+    [ ... myspider starts crawling and appends the result to the file myfile in csv format ... ]
 
 .. command:: check
 
@@ -591,15 +614,13 @@ Example:
 
 .. code-block:: python
 
-    COMMANDS_MODULE = 'mybot.commands'
+    COMMANDS_MODULE = "mybot.commands"
 
 .. _Deploying your project: https://scrapyd.readthedocs.io/en/latest/deploy.html
 
 Register commands via setup.py entry points
 -------------------------------------------
 
-.. note:: This is an experimental feature, use with caution.
-
 You can also add Scrapy commands from an external library by adding a
 ``scrapy.commands`` section in the entry points of the library ``setup.py``
 file.
@@ -612,10 +633,11 @@ The following example adds ``my_command`` command:
 
   from setuptools import setup, find_packages
 
-  setup(name='scrapy-mymodule',
-    entry_points={
-      'scrapy.commands': [
-        'my_command=my_scrapy_module.commands:MyCommand',
-      ],
-    },
-   )
+  setup(
+      name="scrapy-mymodule",
+      entry_points={
+          "scrapy.commands": [
+              "my_command=my_scrapy_module.commands:MyCommand",
+          ],
+      },
+  )

docs/topics/components.rst

@@ -0,0 +1,86 @@
+.. _topics-components:
+
+==========
+Components
+==========
+
+A Scrapy component is any class whose objects are created using
+:func:`scrapy.utils.misc.create_instance`.
+
+That includes the classes that you may assign to the following settings:
+
+-   :setting:`DNS_RESOLVER`
+
+-   :setting:`DOWNLOAD_HANDLERS`
+
+-   :setting:`DOWNLOADER_CLIENTCONTEXTFACTORY`
+
+-   :setting:`DOWNLOADER_MIDDLEWARES`
+
+-   :setting:`DUPEFILTER_CLASS`
+
+-   :setting:`EXTENSIONS`
+
+-   :setting:`FEED_EXPORTERS`
+
+-   :setting:`FEED_STORAGES`
+
+-   :setting:`ITEM_PIPELINES`
+
+-   :setting:`SCHEDULER`
+
+-   :setting:`SCHEDULER_DISK_QUEUE`
+
+-   :setting:`SCHEDULER_MEMORY_QUEUE`
+
+-   :setting:`SCHEDULER_PRIORITY_QUEUE`
+
+-   :setting:`SPIDER_MIDDLEWARES`
+
+Third-party Scrapy components may also let you define additional Scrapy
+components, usually configurable through :ref:`settings <topics-settings>`, to
+modify their behavior.
+
+.. _enforce-component-requirements:
+
+Enforcing component requirements
+================================
+
+Sometimes, your components may only be intended to work under certain
+conditions. For example, they may require a minimum version of Scrapy to work as
+intended, or they may require certain settings to have specific values.
+
+In addition to describing those conditions in the documentation of your
+component, it is a good practice to raise an exception from the ``__init__``
+method of your component if those conditions are not met at run time.
+
+In the case of :ref:`downloader middlewares <topics-downloader-middleware>`,
+:ref:`extensions <topics-extensions>`, :ref:`item pipelines
+<topics-item-pipeline>`, and :ref:`spider middlewares
+<topics-spider-middleware>`, you should raise
+:exc:`scrapy.exceptions.NotConfigured`, passing a description of the issue as a
+parameter to the exception so that it is printed in the logs, for the user to
+see. For other components, feel free to raise whatever other exception feels
+right to you; for example, :exc:`RuntimeError` would make sense for a Scrapy
+version mismatch, while :exc:`ValueError` may be better if the issue is the
+value of a setting.
+
+If your requirement is a minimum Scrapy version, you may use
+:attr:`scrapy.__version__` to enforce your requirement. For example:
+
+.. code-block:: python
+
+    from packaging.version import parse as parse_version
+
+    import scrapy
+
+
+    class MyComponent:
+        def __init__(self):
+            if parse_version(scrapy.__version__) < parse_version("2.7"):
+                raise RuntimeError(
+                    f"{MyComponent.__qualname__} requires Scrapy 2.7 or "
+                    f"later, which allow defining the process_spider_output "
+                    f"method of spider middlewares as an asynchronous "
+                    f"generator."
+                )

docs/topics/contracts.rst

@@ -11,10 +11,13 @@ integrated way of testing your spiders by the means of contracts.
 This allows you to test each callback of your spider by hardcoding a sample url
 and check various constraints for how the callback processes the response. Each
 contract is prefixed with an ``@`` and included in the docstring. See the
-following example::
+following example:
+
+.. code-block:: python
 
     def parse(self, response):
-        """ This function parses a sample response. Some contracts are mingled
+        """
+        This function parses a sample response. Some contracts are mingled
         with this docstring.
 
         @url http://www.amazon.com/s?field-keywords=selfish+gene
@@ -37,7 +40,7 @@ This callback is tested using three built-in contracts:
 
 .. class:: CallbackKeywordArgumentsContract
 
-    This contract (``@cb_kwargs``) sets the :attr:`cb_kwargs <scrapy.http.Request.cb_kwargs>`
+    This contract (``@cb_kwargs``) sets the :attr:`cb_kwargs <scrapy.Request.cb_kwargs>`
     attribute for the sample request. It must be a valid JSON dictionary.
     ::
 
@@ -64,11 +67,13 @@ Custom Contracts
 
 If you find you need more power than the built-in Scrapy contracts you can
 create and load your own contracts in the project by using the
-:setting:`SPIDER_CONTRACTS` setting::
+:setting:`SPIDER_CONTRACTS` setting:
+
+.. code-block:: python
 
     SPIDER_CONTRACTS = {
-        'myproject.contracts.ResponseCheck': 10,
-        'myproject.contracts.ItemValidate': 10,
+        "myproject.contracts.ResponseCheck": 10,
+        "myproject.contracts.ItemValidate": 10,
     }
 
 Each contract must inherit from :class:`~scrapy.contracts.Contract` and can
@@ -88,7 +93,7 @@ override three methods:
     .. method:: Contract.adjust_request_args(args)
 
         This receives a ``dict`` as an argument containing default arguments
-        for request object. :class:`~scrapy.http.Request` is used by default,
+        for request object. :class:`~scrapy.Request` is used by default,
         but this can be changed with the ``request_cls`` attribute.
         If multiple contracts in chain have this attribute defined, the last one is used.
 
@@ -102,7 +107,7 @@ override three methods:
     .. method:: Contract.post_process(output)
 
         This allows processing the output of the callback. Iterators are
-        converted listified before being passed to this hook.
+        converted to lists before being passed to this hook.
 
 Raise :class:`~scrapy.exceptions.ContractFail` from
 :class:`~scrapy.contracts.Contract.pre_process` or
@@ -111,22 +116,27 @@ Raise :class:`~scrapy.exceptions.ContractFail` from
 .. autoclass:: scrapy.exceptions.ContractFail
 
 Here is a demo contract which checks the presence of a custom header in the
-response received::
+response received:
+
+.. skip: next
+.. code-block:: python
 
     from scrapy.contracts import Contract
     from scrapy.exceptions import ContractFail
 
+
     class HasHeaderContract(Contract):
-        """ Demo contract which checks the presence of a custom header
-            @has_header X-CustomHeader
+        """
+        Demo contract which checks the presence of a custom header
+        @has_header X-CustomHeader
         """
 
-        name = 'has_header'
+        name = "has_header"
 
         def pre_process(self, response):
             for header in self.args:
                 if header not in response.headers:
-                    raise ContractFail('X-CustomHeader not present')
+                    raise ContractFail("X-CustomHeader not present")
 
 .. _detecting-contract-check-runs:
 
@@ -135,14 +145,17 @@ Detecting check runs
 
 When ``scrapy check`` is running, the ``SCRAPY_CHECK`` environment variable is
 set to the ``true`` string. You can use :data:`os.environ` to perform any change to
-your spiders or your settings when ``scrapy check`` is used::
+your spiders or your settings when ``scrapy check`` is used:
+
+.. code-block:: python
 
     import os
     import scrapy
 
+
     class ExampleSpider(scrapy.Spider):
-        name = 'example'
+        name = "example"
 
         def __init__(self):
-            if os.environ.get('SCRAPY_CHECK'):
+            if os.environ.get("SCRAPY_CHECK"):
                 pass  # Do some scraper adjustments when a check is running

docs/topics/coroutines.rst

@@ -1,3 +1,5 @@
+.. _topics-coroutines:
+
 ==========
 Coroutines
 ==========
@@ -15,16 +17,14 @@ Supported callables
 The following callables may be defined as coroutines using ``async def``, and
 hence use coroutine syntax (e.g. ``await``, ``async for``, ``async with``):
 
--   :class:`~scrapy.http.Request` callbacks.
+-   :class:`~scrapy.Request` callbacks.
 
-    .. note:: The callback output is not processed until the whole callback
-        finishes.
+    If you are using any custom or third-party :ref:`spider middleware
+    <topics-spider-middleware>`, see :ref:`sync-async-spider-middleware`.
 
-        As a side effect, if the callback raises an exception, none of its
-        output is processed.
-
-        This is a known caveat of the current implementation that we aim to
-        address in a future version of Scrapy.
+    .. versionchanged:: 2.7
+       Output of async callbacks is now processed asynchronously instead of
+       collecting all of it first.
 
 -   The :meth:`process_item` method of
     :ref:`item pipelines <topics-item-pipeline>`.
@@ -39,59 +39,88 @@ hence use coroutine syntax (e.g. ``await``, ``async for``, ``async with``):
 
 -   :ref:`Signal handlers that support deferreds <signal-deferred>`.
 
-Usage
-=====
+-   The
+    :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output`
+    method of :ref:`spider middlewares <topics-spider-middleware>`.
 
-There are several use cases for coroutines in Scrapy. Code that would
-return Deferreds when written for previous Scrapy versions, such as downloader
-middlewares and signal handlers, can be rewritten to be shorter and cleaner::
+    It must be defined as an :term:`asynchronous generator`. The input
+    ``result`` parameter is an :term:`asynchronous iterable`.
+
+    See also :ref:`sync-async-spider-middleware` and
+    :ref:`universal-spider-middleware`.
+
+    .. versionadded:: 2.7
+
+General usage
+=============
+
+There are several use cases for coroutines in Scrapy.
+
+Code that would return Deferreds when written for previous Scrapy versions,
+such as downloader middlewares and signal handlers, can be rewritten to be
+shorter and cleaner:
+
+.. code-block:: python
 
     from itemadapter import ItemAdapter
 
+
     class DbPipeline:
         def _update_item(self, data, item):
             adapter = ItemAdapter(item)
-            adapter['field'] = data
+            adapter["field"] = data
             return item
 
         def process_item(self, item, spider):
             adapter = ItemAdapter(item)
-            dfd = db.get_some_data(adapter['id'])
+            dfd = db.get_some_data(adapter["id"])
             dfd.addCallback(self._update_item, item)
             return dfd
 
-becomes::
+becomes:
+
+.. code-block:: python
 
     from itemadapter import ItemAdapter
 
+
     class DbPipeline:
         async def process_item(self, item, spider):
             adapter = ItemAdapter(item)
-            adapter['field'] = await db.get_some_data(adapter['id'])
+            adapter["field"] = await db.get_some_data(adapter["id"])
             return item
 
 Coroutines may be used to call asynchronous code. This includes other
 coroutines, functions that return Deferreds and functions that return
 :term:`awaitable objects <awaitable>` such as :class:`~asyncio.Future`.
-This means you can use many useful Python libraries providing such code::
+This means you can use many useful Python libraries providing such code:
 
-    class MySpider(Spider):
+.. skip: next
+.. code-block:: python
+
+    class MySpiderDeferred(Spider):
         # ...
-        async def parse_with_deferred(self, response):
-            additional_response = await treq.get('https://additional.url')
+        async def parse(self, response):
+            additional_response = await treq.get("https://additional.url")
             additional_data = await treq.content(additional_response)
             # ... use response and additional_data to yield items and requests
 
-        async def parse_with_asyncio(self, response):
+
+    class MySpiderAsyncio(Spider):
+        # ...
+        async def parse(self, response):
             async with aiohttp.ClientSession() as session:
-                async with session.get('https://additional.url') as additional_response:
-                    additional_data = await r.text()
+                async with session.get("https://additional.url") as additional_response:
+                    additional_data = await additional_response.text()
             # ... use response and additional_data to yield items and requests
 
 .. note:: Many libraries that use coroutines, such as `aio-libs`_, require the
           :mod:`asyncio` loop and to use them you need to
           :doc:`enable asyncio support in Scrapy<asyncio>`.
 
+.. note:: If you want to ``await`` on Deferreds while using the asyncio reactor,
+          you need to :ref:`wrap them<asyncio-await-dfd>`.
+
 Common use cases for asynchronous code include:
 
 * requesting data from websites, databases and other services (in callbacks,
@@ -99,7 +128,159 @@ Common use cases for asynchronous code include:
 * storing data in databases (in pipelines and middlewares);
 * delaying the spider initialization until some external event (in the
   :signal:`spider_opened` handler);
-* calling asynchronous Scrapy methods like ``ExecutionEngine.download`` (see
-  :ref:`the screenshot pipeline example<ScreenshotPipeline>`).
+* calling asynchronous Scrapy methods like :meth:`ExecutionEngine.download`
+  (see :ref:`the screenshot pipeline example<ScreenshotPipeline>`).
 
 .. _aio-libs: https://github.com/aio-libs
+
+
+.. _inline-requests:
+
+Inline requests
+===============
+
+The spider below shows how to send a request and await its response all from
+within a spider callback:
+
+.. code-block:: python
+
+    from scrapy import Spider, Request
+    from scrapy.utils.defer import maybe_deferred_to_future
+
+
+    class SingleRequestSpider(Spider):
+        name = "single"
+        start_urls = ["https://example.org/product"]
+
+        async def parse(self, response, **kwargs):
+            additional_request = Request("https://example.org/price")
+            deferred = self.crawler.engine.download(additional_request)
+            additional_response = await maybe_deferred_to_future(deferred)
+            yield {
+                "h1": response.css("h1").get(),
+                "price": additional_response.css("#price").get(),
+            }
+
+You can also send multiple requests in parallel:
+
+.. code-block:: python
+
+    from scrapy import Spider, Request
+    from scrapy.utils.defer import maybe_deferred_to_future
+    from twisted.internet.defer import DeferredList
+
+
+    class MultipleRequestsSpider(Spider):
+        name = "multiple"
+        start_urls = ["https://example.com/product"]
+
+        async def parse(self, response, **kwargs):
+            additional_requests = [
+                Request("https://example.com/price"),
+                Request("https://example.com/color"),
+            ]
+            deferreds = []
+            for r in additional_requests:
+                deferred = self.crawler.engine.download(r)
+                deferreds.append(deferred)
+            responses = await maybe_deferred_to_future(DeferredList(deferreds))
+            yield {
+                "h1": response.css("h1::text").get(),
+                "price": responses[0][1].css(".price::text").get(),
+                "price2": responses[1][1].css(".color::text").get(),
+            }
+
+
+.. _sync-async-spider-middleware:
+
+Mixing synchronous and asynchronous spider middlewares
+======================================================
+
+.. versionadded:: 2.7
+
+The output of a :class:`~scrapy.Request` callback is passed as the ``result``
+parameter to the
+:meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output` method
+of the first :ref:`spider middleware <topics-spider-middleware>` from the
+:ref:`list of active spider middlewares <topics-spider-middleware-setting>`.
+Then the output of that ``process_spider_output`` method is passed to the
+``process_spider_output`` method of the next spider middleware, and so on for
+every active spider middleware.
+
+Scrapy supports mixing :ref:`coroutine methods <async>` and synchronous methods
+in this chain of calls.
+
+However, if any of the ``process_spider_output`` methods is defined as a
+synchronous method, and the previous ``Request`` callback or
+``process_spider_output`` method is a coroutine, there are some drawbacks to
+the asynchronous-to-synchronous conversion that Scrapy does so that the
+synchronous ``process_spider_output`` method gets a synchronous iterable as its
+``result`` parameter:
+
+-   The whole output of the previous ``Request`` callback or
+    ``process_spider_output`` method is awaited at this point.
+
+-   If an exception raises while awaiting the output of the previous
+    ``Request`` callback or ``process_spider_output`` method, none of that
+    output will be processed.
+
+    This contrasts with the regular behavior, where all items yielded before
+    an exception raises are processed.
+
+Asynchronous-to-synchronous conversions are supported for backward
+compatibility, but they are deprecated and will stop working in a future
+version of Scrapy.
+
+To avoid asynchronous-to-synchronous conversions, when defining ``Request``
+callbacks as coroutine methods or when using spider middlewares whose
+``process_spider_output`` method is an :term:`asynchronous generator`, all
+active spider middlewares must either have their ``process_spider_output``
+method defined as an asynchronous generator or :ref:`define a
+process_spider_output_async method <universal-spider-middleware>`.
+
+.. note:: When using third-party spider middlewares that only define a
+          synchronous ``process_spider_output`` method, consider
+          :ref:`making them universal <universal-spider-middleware>` through
+          :ref:`subclassing <tut-inheritance>`.
+
+
+.. _universal-spider-middleware:
+
+Universal spider middlewares
+============================
+
+.. versionadded:: 2.7
+
+To allow writing a spider middleware that supports asynchronous execution of
+its ``process_spider_output`` method in Scrapy 2.7 and later (avoiding
+:ref:`asynchronous-to-synchronous conversions <sync-async-spider-middleware>`)
+while maintaining support for older Scrapy versions, you may define
+``process_spider_output`` as a synchronous method and define an
+:term:`asynchronous generator` version of that method with an alternative name:
+``process_spider_output_async``.
+
+For example:
+
+.. code-block:: python
+
+    class UniversalSpiderMiddleware:
+        def process_spider_output(self, response, result, spider):
+            for r in result:
+                # ... do something with r
+                yield r
+
+        async def process_spider_output_async(self, response, result, spider):
+            async for r in result:
+                # ... do something with r
+                yield r
+
+.. note:: This is an interim measure to allow, for a time, to write code that
+          works in Scrapy 2.7 and later without requiring
+          asynchronous-to-synchronous conversions, and works in earlier Scrapy
+          versions as well.
+
+          In some future version of Scrapy, however, this feature will be
+          deprecated and, eventually, in a later version of Scrapy, this
+          feature will be removed, and all spider middlewares will be expected
+          to define their ``process_spider_output`` method as an asynchronous
+          generator.

docs/topics/debug.rst

@@ -5,21 +5,25 @@ Debugging Spiders
 =================
 
 This document explains the most common techniques for debugging spiders.
-Consider the following Scrapy spider below::
+Consider the following Scrapy spider below:
+
+.. skip: next
+.. code-block:: python
 
     import scrapy
     from myproject.items import MyItem
 
+
     class MySpider(scrapy.Spider):
-        name = 'myspider'
+        name = "myspider"
         start_urls = (
-            'http://example.com/page1',
-            'http://example.com/page2',
-            )
+            "http://example.com/page1",
+            "http://example.com/page2",
+        )
 
         def parse(self, response):
             # <processing code not shown>
-            # collect `item_urls` 
+            # collect `item_urls`
             for item_url in item_urls:
                 yield scrapy.Request(item_url, self.parse_item)
 
@@ -28,7 +32,9 @@ Consider the following Scrapy spider below::
             item = MyItem()
             # populate `item` fields
             # and extract item_details_url
-            yield scrapy.Request(item_details_url, self.parse_details, cb_kwargs={'item': item})
+            yield scrapy.Request(
+                item_details_url, self.parse_details, cb_kwargs={"item": item}
+            )
 
         def parse_details(self, response, item):
             # populate more `item` fields
@@ -36,7 +42,7 @@ Consider the following Scrapy spider below::
 
 Basically this is a simple spider which parses two pages of items (the
 start_urls). Items also have a details page with additional information, so we
-use the ``cb_kwargs`` functionality of :class:`~scrapy.http.Request` to pass a
+use the ``cb_kwargs`` functionality of :class:`~scrapy.Request` to pass a
 partially populated item.
 
 
@@ -103,10 +109,13 @@ showing the response received and the output. How to debug the situation when
 .. highlight:: python
 
 Fortunately, the :command:`shell` is your bread and butter in this case (see
-:ref:`topics-shell-inspect-response`)::
+:ref:`topics-shell-inspect-response`):
+
+.. code-block:: python
 
     from scrapy.shell import inspect_response
 
+
     def parse_details(self, response, item=None):
         if item:
             # populate more `item` fields
@@ -121,10 +130,13 @@ Open in browser
 
 Sometimes you just want to see how a certain response looks in a browser, you
 can use the ``open_in_browser`` function for that. Here is an example of how
-you would use it::
+you would use it:
+
+.. code-block:: python
 
     from scrapy.utils.response import open_in_browser
 
+
     def parse_details(self, response):
         if "item name" not in response.body:
             open_in_browser(response)
@@ -138,15 +150,47 @@ Logging
 
 Logging is another useful option for getting information about your spider run.
 Although not as convenient, it comes with the advantage that the logs will be
-available in all future runs should they be necessary again::
+available in all future runs should they be necessary again:
+
+.. code-block:: python
 
     def parse_details(self, response, item=None):
         if item:
             # populate more `item` fields
             return item
         else:
-            self.logger.warning('No item received for %s', response.url)
+            self.logger.warning("No item received for %s", response.url)
 
 For more information, check the :ref:`topics-logging` section.
 
 .. _base tag: https://www.w3schools.com/tags/tag_base.asp
+
+.. _debug-vscode:
+
+Visual Studio Code
+==================
+
+.. highlight:: json
+
+To debug spiders with Visual Studio Code you can use the following ``launch.json``::
+
+    {
+        "version": "0.1.0",
+        "configurations": [
+            {
+                "name": "Python: Launch Scrapy Spider",
+                "type": "python",
+                "request": "launch",
+                "module": "scrapy",
+                "args": [
+                    "runspider",
+                    "${file}"
+                ],
+                "console": "integratedTerminal"
+            }
+        ]
+    }
+
+
+Also, make sure you enable "User Uncaught Exceptions", to catch exceptions in
+your Scrapy spider.

docs/topics/deploy.rst

@@ -14,7 +14,7 @@ spiders come in.
 Popular choices for deploying Scrapy spiders are:
 
 * :ref:`Scrapyd <deploy-scrapyd>` (open source)
-* :ref:`Scrapy Cloud <deploy-scrapy-cloud>` (cloud-based)
+* :ref:`Zyte Scrapy Cloud <deploy-scrapy-cloud>` (cloud-based)
 
 .. _deploy-scrapyd:
 
@@ -32,28 +32,28 @@ Scrapyd is maintained by some of the Scrapy developers.
 
 .. _deploy-scrapy-cloud:
 
-Deploying to Scrapy Cloud
-=========================
+Deploying to Zyte Scrapy Cloud
+==============================
 
-`Scrapy Cloud`_ is a hosted, cloud-based service by `Scrapinghub`_,
-the company behind Scrapy.
+`Zyte Scrapy Cloud`_ is a hosted, cloud-based service by Zyte_, the company
+behind Scrapy.
 
-Scrapy Cloud removes the need to setup and monitor servers
-and provides a nice UI to manage spiders and review scraped items,
-logs and stats.
+Zyte Scrapy Cloud removes the need to setup and monitor servers and provides a
+nice UI to manage spiders and review scraped items, logs and stats.
 
-To deploy spiders to Scrapy Cloud you can use the `shub`_ command line tool.
-Please refer to the `Scrapy Cloud documentation`_ for more information.
+To deploy spiders to Zyte Scrapy Cloud you can use the `shub`_ command line
+tool.
+Please refer to the `Zyte Scrapy Cloud documentation`_ for more information.
 
-Scrapy Cloud is compatible with Scrapyd and one can switch between
+Zyte Scrapy Cloud is compatible with Scrapyd and one can switch between
 them as needed - the configuration is read from the ``scrapy.cfg`` file
 just like ``scrapyd-deploy``.
 
-.. _Scrapyd: https://github.com/scrapy/scrapyd
 .. _Deploying your project: https://scrapyd.readthedocs.io/en/latest/deploy.html
-.. _Scrapy Cloud: https://scrapinghub.com/scrapy-cloud
+.. _Scrapyd: https://github.com/scrapy/scrapyd
 .. _scrapyd-client: https://github.com/scrapy/scrapyd-client
-.. _shub: https://doc.scrapinghub.com/shub.html
 .. _scrapyd-deploy documentation: https://scrapyd.readthedocs.io/en/latest/deploy.html
-.. _Scrapy Cloud documentation: https://doc.scrapinghub.com/scrapy-cloud.html
-.. _Scrapinghub: https://scrapinghub.com/
+.. _shub: https://shub.readthedocs.io/en/latest/
+.. _Zyte: https://zyte.com/
+.. _Zyte Scrapy Cloud: https://www.zyte.com/scrapy-cloud/
+.. _Zyte Scrapy Cloud documentation: https://docs.zyte.com/scrapy-cloud.html

docs/topics/developer-tools.rst

@@ -19,14 +19,14 @@ Caveats with inspecting the live browser DOM
 
 Since Developer Tools operate on a live browser DOM, what you'll actually see
 when inspecting the page source is not the original HTML, but a modified one
-after applying some browser clean up and executing Javascript code.  Firefox,
+after applying some browser clean up and executing JavaScript code.  Firefox,
 in particular, is known for adding ``<tbody>`` elements to tables.  Scrapy, on
 the other hand, does not modify the original page HTML, so you won't be able to
 extract any data if you use ``<tbody>`` in your XPath expressions.
 
 Therefore, you should keep in mind the following things:
 
-* Disable Javascript while inspecting the DOM looking for XPaths to be
+* Disable JavaScript while inspecting the DOM looking for XPaths to be
   used in Scrapy (in the Developer Tools settings click `Disable JavaScript`)
 
 * Never use full XPath paths, use relative and clever ones based on attributes
@@ -81,21 +81,23 @@ clicking directly on the tag. If we expand the ``span`` tag with the ``class=
 "text"`` we will see the quote-text we clicked on. The `Inspector` lets you
 copy XPaths to selected elements. Let's try it out.
 
-First open the Scrapy shell at http://quotes.toscrape.com/ in a terminal:
+First open the Scrapy shell at https://quotes.toscrape.com/ in a terminal:
 
 .. code-block:: none
 
-    $ scrapy shell "http://quotes.toscrape.com/"
+    $ scrapy shell "https://quotes.toscrape.com/"
 
 Then, back to your web browser, right-click on the ``span`` tag, select
 ``Copy > XPath`` and paste it in the Scrapy shell like so:
 
 .. invisible-code-block: python
 
-    response = load_response('http://quotes.toscrape.com/', 'quotes.html')
+    response = load_response('https://quotes.toscrape.com/', 'quotes.html')
 
->>> response.xpath('/html/body/div/div[2]/div[1]/div[1]/span[1]/text()').getall()
-['“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”']
+.. code-block:: pycon
+
+  >>> response.xpath("/html/body/div/div[2]/div[1]/div[1]/span[1]/text()").getall()
+  ['“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”']
 
 Adding ``text()`` at the end we are able to extract the first quote with this
 basic selector. But this XPath is not really that clever. All it does is
@@ -124,11 +126,13 @@ With this knowledge we can refine our XPath: Instead of a path to follow,
 we'll simply select all ``span`` tags with the ``class="text"`` by using
 the `has-class-extension`_:
 
->>> response.xpath('//span[has-class("text")]/text()').getall()
-['“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”',
-'“It is our choices, Harry, that show what we truly are, far more than our abilities.”',
-'“There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”',
-...]
+.. code-block:: pycon
+
+    >>> response.xpath('//span[has-class("text")]/text()').getall()
+    ['“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”',
+    '“It is our choices, Harry, that show what we truly are, far more than our abilities.”',
+    '“There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”',
+    ...]
 
 And with one simple, cleverer XPath we are able to extract all quotes from
 the page. We could have constructed a loop over our first XPath to increase
@@ -227,7 +231,7 @@ interests us is the one request called ``quotes?page=1`` with the
 type ``json``.
 
 If we click on this request, we see that the request URL is
-``http://quotes.toscrape.com/api/quotes?page=1`` and the response
+``https://quotes.toscrape.com/api/quotes?page=1`` and the response
 is a JSON-object that contains our quotes. We can also right-click
 on the request and open ``Open in new tab`` to get a better overview.
 
@@ -237,17 +241,19 @@ on the request and open ``Open in new tab`` to get a better overview.
    :alt: JSON-object returned from the quotes.toscrape API
 
 With this response we can now easily parse the JSON-object and
-also request each page to get every quote on the site::
+also request each page to get every quote on the site:
+
+.. code-block:: python
 
     import scrapy
     import json
 
 
     class QuoteSpider(scrapy.Spider):
-        name = 'quote'
-        allowed_domains = ['quotes.toscrape.com']
+        name = "quote"
+        allowed_domains = ["quotes.toscrape.com"]
         page = 1
-        start_urls = ['http://quotes.toscrape.com/api/quotes?page=1']
+        start_urls = ["https://quotes.toscrape.com/api/quotes?page=1"]
 
         def parse(self, response):
             data = json.loads(response.text)
@@ -255,7 +261,7 @@ also request each page to get every quote on the site::
                 yield {"quote": quote["text"]}
             if data["has_next"]:
                 self.page += 1
-                url = f"http://quotes.toscrape.com/api/quotes?page={self.page}"
+                url = f"https://quotes.toscrape.com/api/quotes?page={self.page}"
                 yield scrapy.Request(url=url, callback=self.parse)
 
 This spider starts at the first page of the quotes-API. With each
@@ -274,19 +280,22 @@ In more complex websites, it could be difficult to easily reproduce the
 requests, as we could need to add ``headers`` or ``cookies`` to make it work.
 In those cases you can export the requests in `cURL <https://curl.haxx.se/>`_
 format, by right-clicking on each of them in the network tool and using the
-:meth:`~scrapy.http.Request.from_curl()` method to generate an equivalent
-request::
+:meth:`~scrapy.Request.from_curl()` method to generate an equivalent
+request:
+
+.. code-block:: python
 
     from scrapy import Request
 
     request = Request.from_curl(
-        "curl 'http://quotes.toscrape.com/api/quotes?page=1' -H 'User-Agent: Mozil"
+        "curl 'https://quotes.toscrape.com/api/quotes?page=1' -H 'User-Agent: Mozil"
         "la/5.0 (X11; Linux x86_64; rv:67.0) Gecko/20100101 Firefox/67.0' -H 'Acce"
         "pt: */*' -H 'Accept-Language: ca,en-US;q=0.7,en;q=0.3' --compressed -H 'X"
         "-Requested-With: XMLHttpRequest' -H 'Proxy-Authorization: Basic QFRLLTAzM"
         "zEwZTAxLTk5MWUtNDFiNC1iZWRmLTJjNGI4M2ZiNDBmNDpAVEstMDMzMTBlMDEtOTkxZS00MW"
         "I0LWJlZGYtMmM0YjgzZmI0MGY0' -H 'Connection: keep-alive' -H 'Referer: http"
-        "://quotes.toscrape.com/scroll' -H 'Cache-Control: max-age=0'")
+        "://quotes.toscrape.com/scroll' -H 'Cache-Control: max-age=0'"
+    )
 
 Alternatively, if you want to know the arguments needed to recreate that
 request you can use the :func:`~scrapy.utils.curl.curl_to_request_kwargs`
@@ -304,8 +313,8 @@ daunting and pages can be very complex, but it (mostly) boils down
 to identifying the correct request and replicating it in your spider.
 
 .. _Developer Tools: https://en.wikipedia.org/wiki/Web_development_tools
-.. _quotes.toscrape.com: http://quotes.toscrape.com
-.. _quotes.toscrape.com/scroll: http://quotes.toscrape.com/scroll
-.. _quotes.toscrape.com/api/quotes?page=10: http://quotes.toscrape.com/api/quotes?page=10
+.. _quotes.toscrape.com: https://quotes.toscrape.com
+.. _quotes.toscrape.com/scroll: https://quotes.toscrape.com/scroll
+.. _quotes.toscrape.com/api/quotes?page=10: https://quotes.toscrape.com/api/quotes?page=10
 .. _has-class-extension: https://parsel.readthedocs.io/en/latest/usage.html#other-xpath-extensions
 

docs/topics/downloader-middleware.rst

@@ -17,10 +17,12 @@ To activate a downloader middleware component, add it to the
 :setting:`DOWNLOADER_MIDDLEWARES` setting, which is a dict whose keys are the
 middleware class paths and their values are the middleware orders.
 
-Here's an example::
+Here's an example:
+
+.. code-block:: python
 
     DOWNLOADER_MIDDLEWARES = {
-        'myproject.middlewares.CustomDownloaderMiddleware': 543,
+        "myproject.middlewares.CustomDownloaderMiddleware": 543,
     }
 
 The :setting:`DOWNLOADER_MIDDLEWARES` setting is merged with the
@@ -42,11 +44,13 @@ previous (or subsequent) middleware being applied.
 If you want to disable a built-in middleware (the ones defined in
 :setting:`DOWNLOADER_MIDDLEWARES_BASE` and enabled by default) you must define it
 in your project's :setting:`DOWNLOADER_MIDDLEWARES` setting and assign ``None``
-as its value.  For example, if you want to disable the user-agent middleware::
+as its value.  For example, if you want to disable the user-agent middleware:
+
+.. code-block:: python
 
     DOWNLOADER_MIDDLEWARES = {
-        'myproject.middlewares.CustomDownloaderMiddleware': 543,
-        'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
+        "myproject.middlewares.CustomDownloaderMiddleware": 543,
+        "scrapy.downloadermiddlewares.useragent.UserAgentMiddleware": None,
     }
 
 Finally, keep in mind that some middlewares may need to be enabled through a
@@ -76,7 +80,7 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       middleware.
 
       :meth:`process_request` should either: return ``None``, return a
-      :class:`~scrapy.http.Response` object, return a :class:`~scrapy.http.Request`
+      :class:`~scrapy.Response` object, return a :class:`~scrapy.http.Request`
       object, or raise :exc:`~scrapy.exceptions.IgnoreRequest`.
 
       If it returns ``None``, Scrapy will continue processing this request, executing all
@@ -88,8 +92,8 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       or the appropriate download function; it'll return that response. The :meth:`process_response`
       methods of installed middleware is always called on every response.
 
-      If it returns a :class:`~scrapy.http.Request` object, Scrapy will stop calling
-      process_request methods and reschedule the returned request. Once the newly returned
+      If it returns a :class:`~scrapy.Request` object, Scrapy will stop calling
+      :meth:`process_request` methods and reschedule the returned request. Once the newly returned
       request is performed, the appropriate middleware chain will be called on
       the downloaded response.
 
@@ -100,22 +104,22 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       ignored and not logged (unlike other exceptions).
 
       :param request: the request being processed
-      :type request: :class:`~scrapy.http.Request` object
+      :type request: :class:`~scrapy.Request` object
 
       :param spider: the spider for which this request is intended
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
    .. method:: process_response(request, response, spider)
 
       :meth:`process_response` should either: return a :class:`~scrapy.http.Response`
-      object, return a :class:`~scrapy.http.Request` object or
+      object, return a :class:`~scrapy.Request` object or
       raise a :exc:`~scrapy.exceptions.IgnoreRequest` exception.
 
       If it returns a :class:`~scrapy.http.Response` (it could be the same given
       response, or a brand-new one), that response will continue to be processed
       with the :meth:`process_response` of the next middleware in the chain.
 
-      If it returns a :class:`~scrapy.http.Request` object, the middleware chain is
+      If it returns a :class:`~scrapy.Request` object, the middleware chain is
       halted and the returned request is rescheduled to be downloaded in the future.
       This is the same behavior as if a request is returned from :meth:`process_request`.
 
@@ -124,13 +128,13 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       exception, it is ignored and not logged (unlike other exceptions).
 
       :param request: the request that originated the response
-      :type request: is a :class:`~scrapy.http.Request` object
+      :type request: is a :class:`~scrapy.Request` object
 
       :param response: the response being processed
       :type response: :class:`~scrapy.http.Response` object
 
       :param spider: the spider for which this response is intended
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
    .. method:: process_exception(request, exception, spider)
 
@@ -139,7 +143,7 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       exception (including an :exc:`~scrapy.exceptions.IgnoreRequest` exception)
 
       :meth:`process_exception` should return: either ``None``,
-      a :class:`~scrapy.http.Response` object, or a :class:`~scrapy.http.Request` object.
+      a :class:`~scrapy.http.Response` object, or a :class:`~scrapy.Request` object.
 
       If it returns ``None``, Scrapy will continue processing this exception,
       executing any other :meth:`process_exception` methods of installed middleware,
@@ -149,19 +153,19 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
       method chain of installed middleware is started, and Scrapy won't bother calling
       any other :meth:`process_exception` methods of middleware.
 
-      If it returns a :class:`~scrapy.http.Request` object, the returned request is
+      If it returns a :class:`~scrapy.Request` object, the returned request is
       rescheduled to be downloaded in the future. This stops the execution of
       :meth:`process_exception` methods of the middleware the same as returning a
       response would.
 
       :param request: the request that generated the exception
-      :type request: is a :class:`~scrapy.http.Request` object
+      :type request: is a :class:`~scrapy.Request` object
 
       :param exception: the raised exception
       :type exception: an ``Exception`` object
 
       :param spider: the spider for which this request is intended
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
    .. method:: from_crawler(cls, crawler)
 
@@ -203,10 +207,15 @@ CookiesMiddleware
    browsers do.
 
    .. caution:: When non-UTF8 encoded byte sequences are passed to a
-      :class:`~scrapy.http.Request`, the ``CookiesMiddleware`` will log
+      :class:`~scrapy.Request`, the ``CookiesMiddleware`` will log
       a warning. Refer to :ref:`topics-logging-advanced-customization`
       to customize the logging behaviour.
 
+   .. caution:: Cookies set via the ``Cookie`` header are not considered by the
+      :ref:`cookies-mw`. If you need to set cookies for a request, use the
+      :class:`Request.cookies <scrapy.Request>` parameter. This is a known
+      current limitation that is being worked on.
+
 The following settings can be used to configure the cookie middleware:
 
 * :setting:`COOKIES_ENABLED`
@@ -221,20 +230,26 @@ There is support for keeping multiple cookie sessions per spider by using the
 :reqmeta:`cookiejar` Request meta key. By default it uses a single cookie jar
 (session), but you can pass an identifier to use different ones.
 
-For example::
+For example:
+
+.. skip: next
+.. code-block:: python
 
     for i, url in enumerate(urls):
-        yield scrapy.Request(url, meta={'cookiejar': i},
-            callback=self.parse_page)
+        yield scrapy.Request(url, meta={"cookiejar": i}, callback=self.parse_page)
 
 Keep in mind that the :reqmeta:`cookiejar` meta key is not "sticky". You need to keep
-passing it along on subsequent requests. For example::
+passing it along on subsequent requests. For example:
+
+.. code-block:: python
 
     def parse_page(self, response):
         # do some processing
-        return scrapy.Request("http://www.example.com/otherpage",
-            meta={'cookiejar': response.meta['cookiejar']},
-            callback=self.parse_other_page)
+        return scrapy.Request(
+            "http://www.example.com/otherpage",
+            meta={"cookiejar": response.meta["cookiejar"]},
+            callback=self.parse_other_page,
+        )
 
 .. setting:: COOKIES_ENABLED
 
@@ -253,7 +268,7 @@ web server and received cookies in :class:`~scrapy.http.Response` will
 **not** be merged with the existing cookies.
 
 For more detailed information see the ``cookies`` parameter in
-:class:`~scrapy.http.Request`.
+:class:`~scrapy.Request`.
 
 .. setting:: COOKIES_DEBUG
 
@@ -318,18 +333,34 @@ HttpAuthMiddleware
     This middleware authenticates all requests generated from certain spiders
     using `Basic access authentication`_ (aka. HTTP auth).
 
-    To enable HTTP authentication from certain spiders, set the ``http_user``
-    and ``http_pass`` attributes of those spiders.
+    To enable HTTP authentication for a spider, set the ``http_user`` and
+    ``http_pass`` spider attributes to the authentication data and the
+    ``http_auth_domain`` spider attribute to the domain which requires this
+    authentication (its subdomains will be also handled in the same way).
+    You can set ``http_auth_domain`` to ``None`` to enable the
+    authentication for all requests but you risk leaking your authentication
+    credentials to unrelated domains.
 
-    Example::
+    .. warning::
+        In previous Scrapy versions HttpAuthMiddleware sent the authentication
+        data with all requests, which is a security problem if the spider
+        makes requests to several different domains. Currently if the
+        ``http_auth_domain`` attribute is not set, the middleware will use the
+        domain of the first request, which will work for some spiders but not
+        for others. In the future the middleware will produce an error instead.
+
+    Example:
+
+    .. code-block:: python
 
         from scrapy.spiders import CrawlSpider
 
-        class SomeIntranetSiteSpider(CrawlSpider):
 
-            http_user = 'someuser'
-            http_pass = 'somepass'
-            name = 'intranet.example.com'
+        class SomeIntranetSiteSpider(CrawlSpider):
+            http_user = "someuser"
+            http_pass = "somepass"
+            http_auth_domain = "intranet.example.com"
+            name = "intranet.example.com"
 
             # .. rest of the spider code omitted ...
 
@@ -347,7 +378,7 @@ HttpCacheMiddleware
     This middleware provides low-level cache to all HTTP requests and responses.
     It has to be combined with a cache storage backend as well as a cache policy.
 
-    Scrapy ships with three HTTP cache storage backends:
+    Scrapy ships with the following HTTP cache storage backends:
 
         * :ref:`httpcache-storage-fs`
         * :ref:`httpcache-storage-dbm`
@@ -496,7 +527,7 @@ defines the methods described below.
       the :signal:`open_spider <spider_opened>` signal.
 
       :param spider: the spider which has been opened
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
     .. method:: close_spider(spider)
 
@@ -504,27 +535,27 @@ defines the methods described below.
       the :signal:`close_spider <spider_closed>` signal.
 
       :param spider: the spider which has been closed
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
     .. method:: retrieve_response(spider, request)
 
       Return response if present in cache, or ``None`` otherwise.
 
       :param spider: the spider which generated the request
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
       :param request: the request to find cached response for
-      :type request: :class:`~scrapy.http.Request` object
+      :type request: :class:`~scrapy.Request` object
 
     .. method:: store_response(spider, request, response)
 
       Store the given response in the cache.
 
       :param spider: the spider for which the response is intended
-      :type spider: :class:`~scrapy.spiders.Spider` object
+      :type spider: :class:`~scrapy.Spider` object
 
       :param request: the corresponding request the spider generated
-      :type request: :class:`~scrapy.http.Request` object
+      :type request: :class:`~scrapy.Request` object
 
       :param response: the response to store in the cache
       :type response: :class:`~scrapy.http.Response` object
@@ -684,11 +715,15 @@ HttpCompressionMiddleware
    This middleware allows compressed (gzip, deflate) traffic to be
    sent/received from web sites.
 
-   This middleware also supports decoding `brotli-compressed`_ responses,
-   provided `brotlipy`_ is installed.
+   This middleware also supports decoding `brotli-compressed`_ as well as
+   `zstd-compressed`_ responses, provided that `brotli`_ or `zstandard`_ is
+   installed, respectively.
 
 .. _brotli-compressed: https://www.ietf.org/rfc/rfc7932.txt
-.. _brotlipy: https://pypi.org/project/brotlipy/
+.. _brotli: https://pypi.org/project/Brotli/
+.. _zstd-compressed: https://www.ietf.org/rfc/rfc8478.txt
+.. _zstandard: https://pypi.org/project/zstandard/
+
 
 HttpCompressionMiddleware Settings
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -714,7 +749,7 @@ HttpProxyMiddleware
 .. class:: HttpProxyMiddleware
 
    This middleware sets the HTTP proxy to use for requests, by setting the
-   ``proxy`` meta value for :class:`~scrapy.http.Request` objects.
+   ``proxy`` meta value for :class:`~scrapy.Request` objects.
 
    Like the Python standard library module :mod:`urllib.request`, it obeys
    the following environment variables:
@@ -741,12 +776,12 @@ RedirectMiddleware
 .. reqmeta:: redirect_urls
 
 The urls which the request goes through (while being redirected) can be found
-in the ``redirect_urls`` :attr:`Request.meta <scrapy.http.Request.meta>` key.
+in the ``redirect_urls`` :attr:`Request.meta <scrapy.Request.meta>` key.
 
 .. reqmeta:: redirect_reasons
 
 The reason behind each redirect in :reqmeta:`redirect_urls` can be found in the
-``redirect_reasons`` :attr:`Request.meta <scrapy.http.Request.meta>` key. For
+``redirect_reasons`` :attr:`Request.meta <scrapy.Request.meta>` key. For
 example: ``[301, 302, 307, 'meta refresh']``.
 
 The format of a reason depends on the middleware that handled the corresponding
@@ -762,20 +797,22 @@ settings (see the settings documentation for more info):
 
 .. reqmeta:: dont_redirect
 
-If :attr:`Request.meta <scrapy.http.Request.meta>` has ``dont_redirect``
+If :attr:`Request.meta <scrapy.Request.meta>` has ``dont_redirect``
 key set to True, the request will be ignored by this middleware.
 
 If you want to handle some redirect status codes in your spider, you can
 specify these in the ``handle_httpstatus_list`` spider attribute.
 
 For example, if you want the redirect middleware to ignore 301 and 302
-responses (and pass them through to your spider) you can do this::
+responses (and pass them through to your spider) you can do this:
+
+.. code-block:: python
 
     class MySpider(CrawlSpider):
         handle_httpstatus_list = [301, 302]
 
 The ``handle_httpstatus_list`` key of :attr:`Request.meta
-<scrapy.http.Request.meta>` can also be used to specify which response codes to
+<scrapy.Request.meta>` can also be used to specify which response codes to
 allow on a per-request basis. You can also set the meta key
 ``handle_httpstatus_all`` to ``True`` if you want to allow any response code
 for a request.
@@ -878,12 +915,18 @@ settings (see the settings documentation for more info):
 * :setting:`RETRY_ENABLED`
 * :setting:`RETRY_TIMES`
 * :setting:`RETRY_HTTP_CODES`
+* :setting:`RETRY_EXCEPTIONS`
 
 .. reqmeta:: dont_retry
 
-If :attr:`Request.meta <scrapy.http.Request.meta>` has ``dont_retry`` key
+If :attr:`Request.meta <scrapy.Request.meta>` has ``dont_retry`` key
 set to True, the request will be ignored by this middleware.
 
+To retry requests from a spider callback, you can use the
+:func:`get_retry_request` function:
+
+.. autofunction:: get_retry_request
+
 RetryMiddleware Settings
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -906,7 +949,7 @@ Default: ``2``
 Maximum number of times to retry, in addition to the first download.
 
 Maximum number of retries can also be specified per-request using
-:reqmeta:`max_retry_times` attribute of :attr:`Request.meta <scrapy.http.Request.meta>`.
+:reqmeta:`max_retry_times` attribute of :attr:`Request.meta <scrapy.Request.meta>`.
 When initialized, the :reqmeta:`max_retry_times` meta key takes higher
 precedence over the :setting:`RETRY_TIMES` setting.
 
@@ -924,6 +967,49 @@ In some cases you may want to add 400 to :setting:`RETRY_HTTP_CODES` because
 it is a common code used to indicate server overload. It is not included by
 default because HTTP specs say so.
 
+.. setting:: RETRY_EXCEPTIONS
+
+RETRY_EXCEPTIONS
+^^^^^^^^^^^^^^^^
+
+Default::
+
+    [
+        'twisted.internet.defer.TimeoutError',
+        'twisted.internet.error.TimeoutError',
+        'twisted.internet.error.DNSLookupError',
+        'twisted.internet.error.ConnectionRefusedError',
+        'twisted.internet.error.ConnectionDone',
+        'twisted.internet.error.ConnectError',
+        'twisted.internet.error.ConnectionLost',
+        'twisted.internet.error.TCPTimedOutError',
+        'twisted.web.client.ResponseFailed',
+        IOError,
+        'scrapy.core.downloader.handlers.http11.TunnelError',
+    ]
+
+List of exceptions to retry.
+
+Each list entry may be an exception type or its import path as a string.
+
+An exception will not be caught when the exception type is not in
+:setting:`RETRY_EXCEPTIONS` or when the maximum number of retries for a request
+has been exceeded (see :setting:`RETRY_TIMES`). To learn about uncaught
+exception propagation, see
+:meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_exception`.
+
+.. setting:: RETRY_PRIORITY_ADJUST
+
+RETRY_PRIORITY_ADJUST
+^^^^^^^^^^^^^^^^^^^^^
+
+Default: ``-1``
+
+Adjust retry request priority relative to original request:
+
+- a positive priority adjust means higher priority.
+- **a negative priority adjust (default) means lower priority.**
+
 
 .. _topics-dlmw-robots:
 
@@ -953,15 +1039,15 @@ RobotsTxtMiddleware
 
     * :ref:`Protego <protego-parser>` (default)
     * :ref:`RobotFileParser <python-robotfileparser>`
-    * :ref:`Reppy <reppy-parser>`
     * :ref:`Robotexclusionrulesparser <rerp-parser>`
+    * :ref:`Reppy <reppy-parser>` (deprecated)
 
     You can change the robots.txt_ parser with the :setting:`ROBOTSTXT_PARSER`
     setting. Or you can also :ref:`implement support for a new parser <support-for-new-robots-parser>`.
 
 .. reqmeta:: dont_obey_robotstxt
 
-If :attr:`Request.meta <scrapy.http.Request.meta>` has
+If :attr:`Request.meta <scrapy.Request.meta>` has
 ``dont_obey_robotstxt`` key set to True
 the request will be ignored by this middleware even if
 :setting:`ROBOTSTXT_OBEY` is enabled.
@@ -980,7 +1066,7 @@ Parsers vary in several aspects:
   (shorter) rule
 
 Performance comparison of different parsers is available at `the following link
-<https://anubhavp28.github.io/gsoc-weekly-checkin-12/>`_.
+<https://github.com/scrapy/scrapy/issues/3969>`_.
 
 .. _protego-parser:
 
@@ -1045,9 +1131,14 @@ In order to use this parser:
 
 * Install `Reppy <https://github.com/seomoz/reppy/>`_ by running ``pip install reppy``
 
+    .. warning:: `Upstream issue #122
+        <https://github.com/seomoz/reppy/issues/122>`_ prevents reppy usage in Python 3.9+.
+        Because of this the Reppy parser is deprecated.
+
 * Set :setting:`ROBOTSTXT_PARSER` setting to
   ``scrapy.robotstxt.ReppyRobotParser``
 
+
 .. _rerp-parser:
 
 Robotexclusionrulesparser
@@ -1075,7 +1166,7 @@ In order to use this parser:
 .. _support-for-new-robots-parser:
 
 Implementing support for a new parser
--------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 You can implement support for a new robots.txt_ parser by subclassing
 the abstract base class :class:`~scrapy.robotstxt.RobotParser` and

docs/topics/dynamic-content.rst

@@ -62,9 +62,9 @@ download the webpage with an HTTP client like curl_ or wget_ and see if the
 information can be found in the response they get.
 
 If they get a response with the desired data, modify your Scrapy
-:class:`~scrapy.http.Request` to match that of the other HTTP client. For
+:class:`~scrapy.Request` to match that of the other HTTP client. For
 example, try using the same user-agent string (:setting:`USER_AGENT`) or the
-same :attr:`~scrapy.http.Request.headers`.
+same :attr:`~scrapy.Request.headers`.
 
 If they also get a response without the desired data, you’ll need to take
 steps to make your request more similar to that of the web browser. See
@@ -81,14 +81,14 @@ Use the :ref:`network tool <topics-network-tool>` of your web browser to see
 how your web browser performs the desired request, and try to reproduce that
 request with Scrapy.
 
-It might be enough to yield a :class:`~scrapy.http.Request` with the same HTTP
+It might be enough to yield a :class:`~scrapy.Request` with the same HTTP
 method and URL. However, you may also need to reproduce the body, headers and
-form parameters (see :class:`~scrapy.http.FormRequest`) of that request.
+form parameters (see :class:`~scrapy.FormRequest`) of that request.
 
 As all major browsers allow to export the requests in `cURL
 <https://curl.haxx.se/>`_ format, Scrapy incorporates the method
-:meth:`~scrapy.http.Request.from_curl()` to generate an equivalent
-:class:`~scrapy.http.Request` from a cURL command. To get more information
+:meth:`~scrapy.Request.from_curl()` to generate an equivalent
+:class:`~scrapy.Request` from a cURL command. To get more information
 visit :ref:`request from curl <requests-from-curl>` inside the network
 tool section.
 
@@ -119,16 +119,20 @@ data from it depends on the type of response:
     <topics-selectors>` as usual.
 
 -   If the response is JSON, use :func:`json.loads` to load the desired data from
-    :attr:`response.text <scrapy.http.TextResponse.text>`::
+    :attr:`response.text <scrapy.http.TextResponse.text>`:
+
+    .. code-block:: python
 
         data = json.loads(response.text)
 
     If the desired data is inside HTML or XML code embedded within JSON data,
     you can load that HTML or XML code into a
-    :class:`~scrapy.selector.Selector` and then
-    :ref:`use it <topics-selectors>` as usual::
+    :class:`~scrapy.Selector` and then
+    :ref:`use it <topics-selectors>` as usual:
 
-        selector = Selector(data['html'])
+    .. code-block:: python
+
+        selector = Selector(data["html"])
 
 -   If the response is JavaScript, or HTML with a ``<script/>`` element
     containing the desired data, see :ref:`topics-parsing-javascript`.
@@ -179,10 +183,12 @@ data from it:
     For example, if the JavaScript code contains a separate line like
     ``var data = {"field": "value"};`` you can extract that data as follows:
 
-    >>> pattern = r'\bvar\s+data\s*=\s*(\{.*?\})\s*;\s*\n'
-    >>> json_data = response.css('script::text').re_first(pattern)
-    >>> json.loads(json_data)
-    {'field': 'value'}
+    .. code-block:: pycon
+
+        >>> pattern = r"\bvar\s+data\s*=\s*(\{.*?\})\s*;\s*\n"
+        >>> json_data = response.css("script::text").re_first(pattern)
+        >>> json.loads(json_data)
+        {'field': 'value'}
 
 -   chompjs_ provides an API to parse JavaScript objects into a :class:`dict`.
 
@@ -190,11 +196,13 @@ data from it:
     ``var data = {field: "value", secondField: "second value"};``
     you can extract that data as follows:
 
-    >>> import chompjs
-    >>> javascript = response.css('script::text').get()
-    >>> data = chompjs.parse_js_object(javascript)
-    >>> data
-    {'field': 'value', 'secondField': 'second value'}
+    .. code-block:: pycon
+
+        >>> import chompjs
+        >>> javascript = response.css("script::text").get()
+        >>> data = chompjs.parse_js_object(javascript)
+        >>> data
+        {'field': 'value', 'secondField': 'second value'}
 
 -   Otherwise, use js2xml_ to convert the JavaScript code into an XML document
     that you can parse using :ref:`selectors <topics-selectors>`.
@@ -202,14 +210,16 @@ data from it:
     For example, if the JavaScript code contains
     ``var data = {field: "value"};`` you can extract that data as follows:
 
-    >>> import js2xml
-    >>> import lxml.etree
-    >>> from parsel import Selector
-    >>> javascript = response.css('script::text').get()
-    >>> xml = lxml.etree.tostring(js2xml.parse(javascript), encoding='unicode')
-    >>> selector = Selector(text=xml)
-    >>> selector.css('var[name="data"]').get()
-    '<var name="data"><object><property name="field"><string>value</string></property></object></var>'
+    .. code-block:: pycon
+
+        >>> import js2xml
+        >>> import lxml.etree
+        >>> from parsel import Selector
+        >>> javascript = response.css("script::text").get()
+        >>> xml = lxml.etree.tostring(js2xml.parse(javascript), encoding="unicode")
+        >>> selector = Selector(text=xml)
+        >>> selector.css('var[name="data"]').get()
+        '<var name="data"><object><property name="field"><string>value</string></property></object></var>'
 
 .. _topics-javascript-rendering:
 
@@ -246,24 +256,49 @@ Using a headless browser
 ========================
 
 A `headless browser`_ is a special web browser that provides an API for
-automation.
+automation. By installing the :ref:`asyncio reactor <install-asyncio>`,
+it is possible to integrate ``asyncio``-based libraries which handle headless browsers.
 
-The easiest way to use a headless browser with Scrapy is to use Selenium_,
-along with `scrapy-selenium`_ for seamless integration.
+One such library is `playwright-python`_ (an official Python port of `playwright`_).
+The following is a simple snippet to illustrate its usage within a Scrapy spider:
 
+.. code-block:: python
+
+    import scrapy
+    from playwright.async_api import async_playwright
+
+
+    class PlaywrightSpider(scrapy.Spider):
+        name = "playwright"
+        start_urls = ["data:,"]  # avoid using the default Scrapy downloader
+
+        async def parse(self, response):
+            async with async_playwright() as pw:
+                browser = await pw.chromium.launch()
+                page = await browser.new_page()
+                await page.goto("https://example.org")
+                title = await page.title()
+                return {"title": title}
+
+
+However, using `playwright-python`_ directly as in the above example
+circumvents most of the Scrapy components (middlewares, dupefilter, etc).
+We recommend using `scrapy-playwright`_ for a better integration.
 
 .. _AJAX: https://en.wikipedia.org/wiki/Ajax_%28programming%29
-.. _chompjs: https://github.com/Nykakin/chompjs
 .. _CSS: https://en.wikipedia.org/wiki/Cascading_Style_Sheets
+.. _JavaScript: https://en.wikipedia.org/wiki/JavaScript
+.. _Splash: https://github.com/scrapinghub/splash
+.. _chompjs: https://github.com/Nykakin/chompjs
 .. _curl: https://curl.haxx.se/
 .. _headless browser: https://en.wikipedia.org/wiki/Headless_browser
-.. _JavaScript: https://en.wikipedia.org/wiki/JavaScript
 .. _js2xml: https://github.com/scrapinghub/js2xml
+.. _playwright-python: https://github.com/microsoft/playwright-python
+.. _playwright: https://github.com/microsoft/playwright
+.. _pyppeteer: https://pyppeteer.github.io/pyppeteer/
 .. _pytesseract: https://github.com/madmaze/pytesseract
-.. _scrapy-selenium: https://github.com/clemfromspace/scrapy-selenium
+.. _scrapy-playwright: https://github.com/scrapy-plugins/scrapy-playwright
 .. _scrapy-splash: https://github.com/scrapy-plugins/scrapy-splash
-.. _Selenium: https://www.selenium.dev/
-.. _Splash: https://github.com/scrapinghub/splash
 .. _tabula-py: https://github.com/chezou/tabula-py
 .. _wget: https://www.gnu.org/software/wget/
-.. _wgrep: https://github.com/stav/wgrep
+.. _wgrep: https://github.com/stav/wgrep

docs/topics/email.rst

@@ -19,19 +19,33 @@ Quick example
 =============
 
 There are two ways to instantiate the mail sender. You can instantiate it using
-the standard ``__init__`` method::
+the standard ``__init__`` method:
+
+.. code-block:: python
 
     from scrapy.mail import MailSender
+
     mailer = MailSender()
 
 Or you can instantiate it passing a Scrapy settings object, which will respect
-the :ref:`settings <topics-email-settings>`::
+the :ref:`settings <topics-email-settings>`:
+
+.. skip: start
+.. code-block:: python
 
     mailer = MailSender.from_settings(settings)
 
-And here is how to use it to send an e-mail (without attachments)::
+And here is how to use it to send an e-mail (without attachments):
 
-    mailer.send(to=["someone@example.com"], subject="Some subject", body="Some body", cc=["another@example.com"])
+.. code-block:: python
+
+    mailer.send(
+        to=["someone@example.com"],
+        subject="Some subject",
+        body="Some body",
+        cc=["another@example.com"],
+    )
+.. skip: end
 
 MailSender class reference
 ==========================

docs/topics/exceptions.rst

@@ -26,11 +26,13 @@ CloseSpider
     :param reason: the reason for closing
     :type reason: str
 
-For example::
+For example:
+
+.. code-block:: python
 
     def parse_page(self, response):
-        if 'Bandwidth exceeded' in response.body:
-            raise CloseSpider('bandwidth_exceeded')
+        if "Bandwidth exceeded" in response.body:
+            raise CloseSpider("bandwidth_exceeded")
 
 DontCloseSpider
 ---------------
@@ -64,10 +66,10 @@ NotConfigured
 This exception can be raised by some components to indicate that they will
 remain disabled. Those components include:
 
- * Extensions
- * Item pipelines
- * Downloader middlewares
- * Spider middlewares
+-   Extensions
+-   Item pipelines
+-   Downloader middlewares
+-   Spider middlewares
 
 The exception must be raised in the component's ``__init__`` method.
 
@@ -85,8 +87,8 @@ StopDownload
 
 .. exception:: StopDownload(fail=True)
 
-Raised from a :class:`~scrapy.signals.bytes_received` signal handler to
-indicate that no further bytes should be downloaded for a response.
+Raised from a :class:`~scrapy.signals.bytes_received` or :class:`~scrapy.signals.headers_received`
+signal handler to indicate that no further bytes should be downloaded for a response.
 
 The ``fail`` boolean parameter controls which method will handle the resulting
 response:
@@ -110,5 +112,6 @@ attribute.
     ``StopDownload(False)`` or ``StopDownload(True)`` will raise
     a :class:`TypeError`.
 
-See the documentation for the :class:`~scrapy.signals.bytes_received` signal
+See the documentation for the :class:`~scrapy.signals.bytes_received` and
+:class:`~scrapy.signals.headers_received` signals
 and the :ref:`topics-stop-response-download` topic for additional information and examples.

docs/topics/exporters.rst

@@ -38,11 +38,14 @@ the end of the exporting process
 
 Here you can see an :doc:`Item Pipeline <item-pipeline>` which uses multiple
 Item Exporters to group scraped items to different files according to the
-value of one of their fields::
+value of one of their fields:
+
+.. code-block:: python
 
     from itemadapter import ItemAdapter
     from scrapy.exporters import XmlItemExporter
 
+
     class PerYearXmlExportPipeline:
         """Distribute items across multiple XML files according to their 'year' field"""
 
@@ -50,18 +53,19 @@ value of one of their fields::
             self.year_to_exporter = {}
 
         def close_spider(self, spider):
-            for exporter in self.year_to_exporter.values():
+            for exporter, xml_file in self.year_to_exporter.values():
                 exporter.finish_exporting()
+                xml_file.close()
 
         def _exporter_for_item(self, item):
             adapter = ItemAdapter(item)
-            year = adapter['year']
+            year = adapter["year"]
             if year not in self.year_to_exporter:
-                f = open(f'{year}.xml', 'wb')
-                exporter = XmlItemExporter(f)
+                xml_file = open(f"{year}.xml", "wb")
+                exporter = XmlItemExporter(xml_file)
                 exporter.start_exporting()
-                self.year_to_exporter[year] = exporter
-            return self.year_to_exporter[year]
+                self.year_to_exporter[year] = (exporter, xml_file)
+            return self.year_to_exporter[year][0]
 
         def process_item(self, item, spider):
             exporter = self._exporter_for_item(item)
@@ -89,16 +93,20 @@ described next.
 1. Declaring a serializer in the field
 --------------------------------------
 
-If you use :class:`~.Item` you can declare a serializer in the
+If you use :class:`~scrapy.Item` you can declare a serializer in the
 :ref:`field metadata <topics-items-fields>`. The serializer must be
 a callable which receives a value and returns its serialized form.
 
-Example::
+Example:
+
+.. code-block:: python
 
     import scrapy
 
+
     def serialize_price(value):
-        return f'$ {str(value)}'
+        return f"$ {str(value)}"
+
 
     class Product(scrapy.Item):
         name = scrapy.Field()
@@ -114,16 +122,18 @@ customize how your field value will be exported.
 Make sure you call the base class :meth:`~BaseItemExporter.serialize_field()` method
 after your custom code.
 
-Example::
+Example:
+
+.. code-block:: python
+
+      from scrapy.exporters import XmlItemExporter
 
-      from scrapy.exporter import XmlItemExporter
 
       class ProductXmlExporter(XmlItemExporter):
-
           def serialize_field(self, field, name, value):
-              if field == 'price':
-                  return f'$ {str(value)}'
-              return super(Product, self).serialize_field(field, name, value)
+              if name == "price":
+                  return f"$ {str(value)}"
+              return super().serialize_field(field, name, value)
 
 .. _topics-exporters-reference:
 
@@ -131,10 +141,13 @@ Built-in Item Exporters reference
 =================================
 
 Here is a list of the Item Exporters bundled with Scrapy. Some of them contain
-output examples, which assume you're exporting these two items::
+output examples, which assume you're exporting these two items:
 
-    Item(name='Color TV', price='1200')
-    Item(name='DVD player', price='200')
+.. skip: next
+.. code-block:: python
+
+    Item(name="Color TV", price="1200")
+    Item(name="DVD player", price="200")
 
 BaseItemExporter
 ----------------
@@ -171,7 +184,7 @@ BaseItemExporter
       :param field: the field being serialized. If the source :ref:`item object
           <item-types>` does not define field metadata, *field* is an empty
           :class:`dict`.
-      :type field: :class:`~scrapy.item.Field` object or a :class:`dict` instance
+      :type field: :class:`~scrapy.Field` object or a :class:`dict` instance
 
       :param name: the name of the field being serialized
       :type name: str
@@ -194,17 +207,25 @@ BaseItemExporter
 
    .. attribute:: fields_to_export
 
-      A list with the name of the fields that will be exported, or ``None`` if
-      you want to export all fields. Defaults to ``None``.
+      Fields to export, their order [1]_ and their output names.
 
-      Some exporters (like :class:`CsvItemExporter`) respect the order of the
-      fields defined in this attribute.
+      Possible values are:
 
-      When using :ref:`item objects <item-types>` that do not expose all their
-      possible fields, exporters that do not support exporting a different
-      subset of fields per item will only export the fields found in the first
-      item exported. Use ``fields_to_export`` to define all the fields to be
-      exported.
+      -   ``None`` (all fields [2]_, default)
+
+      -   A list of fields::
+
+              ['field1', 'field2']
+
+      -   A dict where keys are fields and values are output names::
+
+              {'field1': 'Field 1', 'field2': 'Field 2'}
+
+      .. [1] Not all exporters respect the specified field order.
+      .. [2] When using :ref:`item objects <item-types>` that do not expose
+             all their possible fields, exporters that do not support exporting
+             a different subset of fields per item will only export the fields 
+             found in the first item exported.
 
    .. attribute:: export_empty_fields
 
@@ -296,8 +317,8 @@ CsvItemExporter
 
    Exports items in CSV format to the given file-like object. If the
    :attr:`fields_to_export` attribute is set, it will be used to define the
-   CSV columns and their order. The :attr:`export_empty_fields` attribute has
-   no effect on this exporter.
+   CSV columns, their order and their column names. The
+   :attr:`export_empty_fields` attribute has no effect on this exporter.
 
    :param file: the file-like object to use for exporting the data. Its ``write`` method should
                 accept ``bytes`` (a disk file opened in binary mode, a ``io.BytesIO`` object, etc)

docs/topics/extensions.rst

@@ -7,8 +7,7 @@ Extensions
 The extensions framework provides a mechanism for inserting your own
 custom functionality into Scrapy.
 
-Extensions are just regular classes that are instantiated at Scrapy startup,
-when extensions are initialized.
+Extensions are just regular classes.
 
 Extension settings
 ==================
@@ -18,7 +17,7 @@ settings, just like any other Scrapy code.
 
 It is customary for extensions to prefix their settings with their own name, to
 avoid collision with existing (and future) extensions. For example, a
-hypothetic extension to handle `Google Sitemaps`_ would use settings like
+hypothetical extension to handle `Google Sitemaps`_ would use settings like
 ``GOOGLESITEMAP_ENABLED``, ``GOOGLESITEMAP_DEPTH``, and so on.
 
 .. _Google Sitemaps: https://en.wikipedia.org/wiki/Sitemaps
@@ -27,16 +26,18 @@ Loading & activating extensions
 ===============================
 
 Extensions are loaded and activated at startup by instantiating a single
-instance of the extension class. Therefore, all the extension initialization
-code must be performed in the class ``__init__`` method.
+instance of the extension class per spider being run. All the extension
+initialization code must be performed in the class ``__init__`` method.
 
 To make an extension available, add it to the :setting:`EXTENSIONS` setting in
 your Scrapy settings. In :setting:`EXTENSIONS`, each extension is represented
-by a string: the full Python path to the extension's class name. For example::
+by a string: the full Python path to the extension's class name. For example:
+
+.. code-block:: python
 
     EXTENSIONS = {
-        'scrapy.extensions.corestats.CoreStats': 500,
-        'scrapy.extensions.telnet.TelnetConsole': 500,
+        "scrapy.extensions.corestats.CoreStats": 500,
+        "scrapy.extensions.telnet.TelnetConsole": 500,
     }
 
 
@@ -65,10 +66,12 @@ Disabling an extension
 
 In order to disable an extension that comes enabled by default (i.e. those
 included in the :setting:`EXTENSIONS_BASE` setting) you must set its order to
-``None``. For example::
+``None``. For example:
+
+.. code-block:: python
 
     EXTENSIONS = {
-        'scrapy.extensions.corestats.CoreStats': None,
+        "scrapy.extensions.corestats.CoreStats": None,
     }
 
 Writing your own extension
@@ -99,7 +102,9 @@ in the previous section. This extension will log a message every time:
 The extension will be enabled through the ``MYEXT_ENABLED`` setting and the
 number of items will be specified through the ``MYEXT_ITEMCOUNT`` setting.
 
-Here is the code of such extension::
+Here is the code of such extension:
+
+.. code-block:: python
 
     import logging
     from scrapy import signals
@@ -107,8 +112,8 @@ Here is the code of such extension::
 
     logger = logging.getLogger(__name__)
 
-    class SpiderOpenCloseLogging:
 
+    class SpiderOpenCloseLogging:
         def __init__(self, item_count):
             self.item_count = item_count
             self.items_scraped = 0
@@ -117,11 +122,11 @@ Here is the code of such extension::
         def from_crawler(cls, crawler):
             # first check if the extension should be enabled and raise
             # NotConfigured otherwise
-            if not crawler.settings.getbool('MYEXT_ENABLED'):
+            if not crawler.settings.getbool("MYEXT_ENABLED"):
                 raise NotConfigured
 
             # get the number of items from settings
-            item_count = crawler.settings.getint('MYEXT_ITEMCOUNT', 1000)
+            item_count = crawler.settings.getint("MYEXT_ITEMCOUNT", 1000)
 
             # instantiate the extension object
             ext = cls(item_count)
@@ -253,10 +258,17 @@ The conditions for closing a spider can be configured through the following
 settings:
 
 * :setting:`CLOSESPIDER_TIMEOUT`
+* :setting:`CLOSESPIDER_TIMEOUT_NO_ITEM`
 * :setting:`CLOSESPIDER_ITEMCOUNT`
 * :setting:`CLOSESPIDER_PAGECOUNT`
 * :setting:`CLOSESPIDER_ERRORCOUNT`
 
+.. note::
+
+   When a certain closing condition is met, requests which are 
+   currently in the downloader queue (up to :setting:`CONCURRENT_REQUESTS` 
+   requests) are still processed.
+
 .. setting:: CLOSESPIDER_TIMEOUT
 
 CLOSESPIDER_TIMEOUT
@@ -269,6 +281,18 @@ more than that number of second, it will be automatically closed with the
 reason ``closespider_timeout``. If zero (or non set), spiders won't be closed by
 timeout.
 
+.. setting:: CLOSESPIDER_TIMEOUT_NO_ITEM
+
+CLOSESPIDER_TIMEOUT_NO_ITEM
+"""""""""""""""""""""""""""
+
+Default: ``0``
+
+An integer which specifies a number of seconds. If the spider has not produced
+any items in the last number of seconds, it will be closed with the reason
+``closespider_timeout_no_item``. If zero (or non set), spiders won't be closed
+regardless if it hasn't produced any items.
+
 .. setting:: CLOSESPIDER_ITEMCOUNT
 
 CLOSESPIDER_ITEMCOUNT
@@ -279,8 +303,6 @@ Default: ``0``
 An integer which specifies a number of items. If the spider scrapes more than
 that amount and those items are passed by the item pipeline, the
 spider will be closed with the reason ``closespider_itemcount``.
-Requests which  are currently in the downloader queue (up to
-:setting:`CONCURRENT_REQUESTS` requests) are still processed.
 If zero (or non set), spiders won't be closed by number of passed items.
 
 .. setting:: CLOSESPIDER_PAGECOUNT
@@ -320,9 +342,130 @@ domain has finished scraping, including the Scrapy stats collected. The email
 will be sent to all recipients specified in the :setting:`STATSMAILER_RCPTS`
 setting.
 
+Emails can be sent using the :class:`~scrapy.mail.MailSender` class. To see a
+full list of parameters, including examples on how to instantiate
+:class:`~scrapy.mail.MailSender` and use mail settings, see
+:ref:`topics-email`.
+
 .. module:: scrapy.extensions.debug
    :synopsis: Extensions for debugging Scrapy
 
+.. module:: scrapy.extensions.periodic_log
+   :synopsis: Periodic stats logging
+
+Periodic log extension
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. class:: PeriodicLog
+
+This extension periodically logs rich stat data as a JSON object::
+
+    2023-08-04 02:30:57 [scrapy.extensions.logstats] INFO: Crawled 976 pages (at 162 pages/min), scraped 925 items (at 161 items/min)
+    2023-08-04 02:30:57 [scrapy.extensions.periodic_log] INFO: {
+        "delta": {
+            "downloader/request_bytes": 55582,
+            "downloader/request_count": 162,
+            "downloader/request_method_count/GET": 162,
+            "downloader/response_bytes": 618133,
+            "downloader/response_count": 162,
+            "downloader/response_status_count/200": 162,
+            "item_scraped_count": 161
+        },
+        "stats": {
+            "downloader/request_bytes": 338243,
+            "downloader/request_count": 992,
+            "downloader/request_method_count/GET": 992,
+            "downloader/response_bytes": 3836736,
+            "downloader/response_count": 976,
+            "downloader/response_status_count/200": 976,
+            "item_scraped_count": 925,
+            "log_count/INFO": 21,
+            "log_count/WARNING": 1,
+            "scheduler/dequeued": 992,
+            "scheduler/dequeued/memory": 992,
+            "scheduler/enqueued": 1050,
+            "scheduler/enqueued/memory": 1050
+        },
+        "time": {
+            "elapsed": 360.008903,
+            "log_interval": 60.0,
+            "log_interval_real": 60.006694,
+            "start_time": "2023-08-03 23:24:57",
+            "utcnow": "2023-08-03 23:30:57"
+        }
+    }
+
+This extension logs the following configurable sections:
+
+-   ``"delta"`` shows how some numeric stats have changed since the last stats
+    log message.
+
+    The :setting:`PERIODIC_LOG_DELTA` setting determines the target stats. They
+    must have ``int`` or ``float`` values.
+
+-   ``"stats"`` shows the current value of some stats.
+
+    The :setting:`PERIODIC_LOG_STATS` setting determines the target stats.
+
+-   ``"time"`` shows detailed timing data.
+
+    The :setting:`PERIODIC_LOG_TIMING_ENABLED` setting determines whether or
+    not to show this section.
+
+This extension logs data at the start, then on a fixed time interval
+configurable through the :setting:`LOGSTATS_INTERVAL` setting, and finally
+right before the crawl ends.
+
+
+Example extension configuration:
+
+.. code-block:: python
+
+    custom_settings = {
+        "LOG_LEVEL": "INFO",
+        "PERIODIC_LOG_STATS": {
+            "include": ["downloader/", "scheduler/", "log_count/", "item_scraped_count/"],
+        },
+        "PERIODIC_LOG_DELTA": {"include": ["downloader/"]},
+        "PERIODIC_LOG_TIMING_ENABLED": True,
+        "EXTENSIONS": {
+            "scrapy.extensions.periodic_log.PeriodicLog": 0,
+        },
+    }
+
+.. setting:: PERIODIC_LOG_DELTA
+
+PERIODIC_LOG_DELTA
+""""""""""""""""""
+
+Default: ``None``
+
+* ``"PERIODIC_LOG_DELTA": True`` - show deltas for all ``int`` and ``float`` stat values.
+* ``"PERIODIC_LOG_DELTA": {"include": ["downloader/", "scheduler/"]}`` - show deltas for stats with names containing any configured substring.
+* ``"PERIODIC_LOG_DELTA": {"exclude": ["downloader/"]}`` - show deltas for all stats with names not containing any configured substring.
+
+.. setting:: PERIODIC_LOG_STATS
+
+PERIODIC_LOG_STATS
+""""""""""""""""""
+
+Default: ``None``
+
+* ``"PERIODIC_LOG_STATS": True`` - show the current value of all stats.
+* ``"PERIODIC_LOG_STATS": {"include": ["downloader/", "scheduler/"]}`` - show current values for stats with names containing any configured substring.
+* ``"PERIODIC_LOG_STATS": {"exclude": ["downloader/"]}`` - show current values for all stats with names not containing any configured substring.
+
+
+.. setting:: PERIODIC_LOG_TIMING_ENABLED
+
+PERIODIC_LOG_TIMING_ENABLED
+"""""""""""""""""""""""""""
+
+Default: ``False``
+
+``True`` enables logging of timing data (i.e. the ``"time"`` section).
+
+
 Debugging extensions
 --------------------
 

docs/topics/feed-exports.rst

@@ -13,6 +13,11 @@ Scrapy provides this functionality out of the box with the Feed Exports, which
 allows you to generate feeds with the scraped items, using multiple
 serialization formats and storage backends.
 
+This page provides detailed documentation for all feed export features. If you
+are looking for a step-by-step guide, check out `Zyte’s export guides`_.
+
+.. _Zyte’s export guides: https://docs.zyte.com/web-scraping/guides/export/index.html#exporting-scraped-data
+
 .. _topics-feed-format:
 
 Serialization formats
@@ -21,10 +26,10 @@ Serialization formats
 For serializing the scraped data, the feed exports use the :ref:`Item exporters
 <topics-exporters>`. These formats are supported out of the box:
 
- * :ref:`topics-feed-format-json`
- * :ref:`topics-feed-format-jsonlines`
- * :ref:`topics-feed-format-csv`
- * :ref:`topics-feed-format-xml`
+-   :ref:`topics-feed-format-json`
+-   :ref:`topics-feed-format-jsonlines`
+-   :ref:`topics-feed-format-csv`
+-   :ref:`topics-feed-format-xml`
 
 But you can also extend the supported format through the
 :setting:`FEED_EXPORTERS` setting.
@@ -34,54 +39,58 @@ But you can also extend the supported format through the
 JSON
 ----
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``json``
- * Exporter used: :class:`~scrapy.exporters.JsonItemExporter`
- * See :ref:`this warning <json-with-large-data>` if you're using JSON with
-   large feeds.
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``json``
+
+-   Exporter used: :class:`~scrapy.exporters.JsonItemExporter`
+
+-   See :ref:`this warning <json-with-large-data>` if you're using JSON with
+    large feeds.
 
 .. _topics-feed-format-jsonlines:
 
 JSON lines
 ----------
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``jsonlines``
- * Exporter used: :class:`~scrapy.exporters.JsonLinesItemExporter`
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``jsonlines``
+-   Exporter used: :class:`~scrapy.exporters.JsonLinesItemExporter`
 
 .. _topics-feed-format-csv:
 
 CSV
 ---
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``csv``
- * Exporter used: :class:`~scrapy.exporters.CsvItemExporter`
- * To specify columns to export and their order use
-   :setting:`FEED_EXPORT_FIELDS`. Other feed exporters can also use this
-   option, but it is important for CSV because unlike many other export
-   formats CSV uses a fixed header.
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``csv``
+
+-   Exporter used: :class:`~scrapy.exporters.CsvItemExporter`
+
+-   To specify columns to export, their order and their column names, use
+    :setting:`FEED_EXPORT_FIELDS`. Other feed exporters can also use this
+    option, but it is important for CSV because unlike many other export
+    formats CSV uses a fixed header.
 
 .. _topics-feed-format-xml:
 
 XML
 ---
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``xml``
- * Exporter used: :class:`~scrapy.exporters.XmlItemExporter`
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``xml``
+-   Exporter used: :class:`~scrapy.exporters.XmlItemExporter`
 
 .. _topics-feed-format-pickle:
 
 Pickle
 ------
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``pickle``
- * Exporter used: :class:`~scrapy.exporters.PickleItemExporter`
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``pickle``
+-   Exporter used: :class:`~scrapy.exporters.PickleItemExporter`
 
 .. _topics-feed-format-marshal:
 
 Marshal
 -------
 
- * Value for the ``format`` key in the :setting:`FEEDS` setting: ``marshal``
- * Exporter used: :class:`~scrapy.exporters.MarshalItemExporter`
+-   Value for the ``format`` key in the :setting:`FEEDS` setting: ``marshal``
+-   Exporter used: :class:`~scrapy.exporters.MarshalItemExporter`
 
 
 .. _topics-feed-storage:
@@ -95,14 +104,14 @@ storage backend types which are defined by the URI scheme.
 
 The storages backends supported out of the box are:
 
- * :ref:`topics-feed-storage-fs`
- * :ref:`topics-feed-storage-ftp`
- * :ref:`topics-feed-storage-s3` (requires botocore_)
- * :ref:`topics-feed-storage-gcs` (requires `google-cloud-storage`_)
- * :ref:`topics-feed-storage-stdout`
+-   :ref:`topics-feed-storage-fs`
+-   :ref:`topics-feed-storage-ftp`
+-   :ref:`topics-feed-storage-s3` (requires boto3_)
+-   :ref:`topics-feed-storage-gcs` (requires `google-cloud-storage`_)
+-   :ref:`topics-feed-storage-stdout`
 
 Some storage backends may be unavailable if the required external libraries are
-not available. For example, the S3 backend is only available if the botocore_
+not available. For example, the S3 backend is only available if the boto3_
 library is installed.
 
 
@@ -114,8 +123,8 @@ Storage URI parameters
 The storage URI can also contain parameters that get replaced when the feed is
 being created. These parameters are:
 
- * ``%(time)s`` - gets replaced by a timestamp when the feed is being created
- * ``%(name)s`` - gets replaced by the spider name
+-   ``%(time)s`` - gets replaced by a timestamp when the feed is being created
+-   ``%(name)s`` - gets replaced by the spider name
 
 Any other named parameter gets replaced by the spider attribute of the same
 name. For example, ``%(site_id)s`` would get replaced by the ``spider.site_id``
@@ -123,13 +132,16 @@ attribute the moment the feed is being created.
 
 Here are some examples to illustrate:
 
- * Store in FTP using one directory per spider:
+-   Store in FTP using one directory per spider:
 
-   * ``ftp://user:password@ftp.example.com/scraping/feeds/%(name)s/%(time)s.json``
+    -   ``ftp://user:password@ftp.example.com/scraping/feeds/%(name)s/%(time)s.json``
 
- * Store in S3 using one directory per spider:
+-   Store in S3 using one directory per spider:
 
-   * ``s3://mybucket/scraping/feeds/%(name)s/%(time)s.json``
+    -   ``s3://mybucket/scraping/feeds/%(name)s/%(time)s.json``
+
+.. note:: :ref:`Spider arguments <spiderargs>` become spider attributes, hence
+          they can also be used as storage URI parameters.
 
 
 .. _topics-feed-storage-backends:
@@ -144,13 +156,13 @@ Local filesystem
 
 The feeds are stored in the local filesystem.
 
- * URI scheme: ``file``
- * Example URI: ``file:///tmp/export.csv``
- * Required external libraries: none
+-   URI scheme: ``file``
+-   Example URI: ``file:///tmp/export.csv``
+-   Required external libraries: none
 
 Note that for the local filesystem storage (only) you can omit the scheme if
-you specify an absolute path like ``/tmp/export.csv``. This only works on Unix
-systems though.
+you specify an absolute path like ``/tmp/export.csv`` (Unix systems only).
+Alternatively you can also use a :class:`pathlib.Path` object.
 
 .. _topics-feed-storage-ftp:
 
@@ -159,15 +171,21 @@ FTP
 
 The feeds are stored in a FTP server.
 
- * URI scheme: ``ftp``
- * Example URI: ``ftp://user:pass@ftp.example.com/path/to/export.csv``
- * Required external libraries: none
+-   URI scheme: ``ftp``
+-   Example URI: ``ftp://user:pass@ftp.example.com/path/to/export.csv``
+-   Required external libraries: none
 
 FTP supports two different connection modes: `active or passive
 <https://stackoverflow.com/a/1699163>`_. Scrapy uses the passive connection
 mode by default. To use the active connection mode instead, set the
 :setting:`FEED_STORAGE_FTP_ACTIVE` setting to ``True``.
 
+The default value for the ``overwrite`` key in the :setting:`FEEDS` for this 
+storage backend is: ``True``.
+
+.. caution:: The value ``True`` in ``overwrite`` will cause you to lose the
+     previous version of your data.
+
 This storage backend uses :ref:`delayed file delivery <delayed-file-delivery>`.
 
 
@@ -178,23 +196,37 @@ S3
 
 The feeds are stored on `Amazon S3`_.
 
- * URI scheme: ``s3``
- * Example URIs:
+-   URI scheme: ``s3``
 
-   * ``s3://mybucket/path/to/export.csv``
-   * ``s3://aws_key:aws_secret@mybucket/path/to/export.csv``
+-   Example URIs:
 
- * Required external libraries: `botocore`_
+    -   ``s3://mybucket/path/to/export.csv``
+
+    -   ``s3://aws_key:aws_secret@mybucket/path/to/export.csv``
+
+-   Required external libraries: `boto3`_ >= 1.20.0
 
 The AWS credentials can be passed as user/password in the URI, or they can be
 passed through the following settings:
 
- * :setting:`AWS_ACCESS_KEY_ID`
- * :setting:`AWS_SECRET_ACCESS_KEY`
+-   :setting:`AWS_ACCESS_KEY_ID`
+-   :setting:`AWS_SECRET_ACCESS_KEY`
+-   :setting:`AWS_SESSION_TOKEN` (only needed for `temporary security credentials`_)
 
-You can also define a custom ACL for exported feeds using this setting:
+.. _temporary security credentials: https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#temporary-access-keys
 
- * :setting:`FEED_STORAGE_S3_ACL`
+You can also define a custom ACL, custom endpoint, and region name for exported
+feeds using these settings:
+
+-   :setting:`FEED_STORAGE_S3_ACL`
+-   :setting:`AWS_ENDPOINT_URL`
+-   :setting:`AWS_REGION_NAME`
+
+The default value for the ``overwrite`` key in the :setting:`FEEDS` for this 
+storage backend is: ``True``.
+
+.. caution:: The value ``True`` in ``overwrite`` will cause you to lose the
+     previous version of your data.
 
 This storage backend uses :ref:`delayed file delivery <delayed-file-delivery>`.
 
@@ -208,19 +240,26 @@ Google Cloud Storage (GCS)
 
 The feeds are stored on `Google Cloud Storage`_.
 
- * URI scheme: ``gs``
- * Example URIs:
+-   URI scheme: ``gs``
 
-   * ``gs://mybucket/path/to/export.csv``
+-   Example URIs:
 
- * Required external libraries: `google-cloud-storage`_.
+    -   ``gs://mybucket/path/to/export.csv``
+
+-   Required external libraries: `google-cloud-storage`_.
 
 For more information about authentication, please refer to `Google Cloud documentation <https://cloud.google.com/docs/authentication/production>`_.
 
 You can set a *Project ID* and *Access Control List (ACL)* through the following settings:
 
- * :setting:`FEED_STORAGE_GCS_ACL`
- * :setting:`GCS_PROJECT_ID`
+-   :setting:`FEED_STORAGE_GCS_ACL`
+-   :setting:`GCS_PROJECT_ID`
+
+The default value for the ``overwrite`` key in the :setting:`FEEDS` for this 
+storage backend is: ``True``.
+
+.. caution:: The value ``True`` in ``overwrite`` will cause you to lose the
+     previous version of your data.
 
 This storage backend uses :ref:`delayed file delivery <delayed-file-delivery>`.
 
@@ -234,9 +273,9 @@ Standard output
 
 The feeds are written to the standard output of the Scrapy process.
 
- * URI scheme: ``stdout``
- * Example URI: ``stdout:``
- * Required external libraries: none
+-   URI scheme: ``stdout``
+-   Example URI: ``stdout:``
+-   Required external libraries: none
 
 
 .. _delayed-file-delivery:
@@ -259,21 +298,119 @@ soon as a file reaches the maximum item count, that file is delivered to the
 feed URI, allowing item delivery to start way before the end of the crawl.
 
 
+.. _item-filter:
+
+Item filtering
+==============
+
+.. versionadded:: 2.6.0
+
+You can filter items that you want to allow for a particular feed by using the
+``item_classes`` option in :ref:`feeds options <feed-options>`. Only items of
+the specified types will be added to the feed.
+
+The ``item_classes`` option is implemented by the :class:`~scrapy.extensions.feedexport.ItemFilter`
+class, which is the default value of the ``item_filter`` :ref:`feed option <feed-options>`.
+
+You can create your own custom filtering class by implementing :class:`~scrapy.extensions.feedexport.ItemFilter`'s
+method ``accepts`` and taking ``feed_options`` as an argument.
+
+For instance:
+
+.. code-block:: python
+
+    class MyCustomFilter:
+        def __init__(self, feed_options):
+            self.feed_options = feed_options
+
+        def accepts(self, item):
+            if "field1" in item and item["field1"] == "expected_data":
+                return True
+            return False
+
+
+You can assign your custom filtering class to the ``item_filter`` :ref:`option of a feed <feed-options>`.
+See :setting:`FEEDS` for examples.
+
+ItemFilter
+----------
+
+.. autoclass:: scrapy.extensions.feedexport.ItemFilter
+   :members:
+
+
+.. _post-processing:
+
+Post-Processing
+===============
+
+.. versionadded:: 2.6.0
+
+Scrapy provides an option to activate plugins to post-process feeds before they are exported
+to feed storages. In addition to using :ref:`builtin plugins <builtin-plugins>`, you
+can create your own :ref:`plugins <custom-plugins>`.
+
+These plugins can be activated through the ``postprocessing`` option of a feed.
+The option must be passed a list of post-processing plugins in the order you want
+the feed to be processed. These plugins can be declared either as an import string
+or with the imported class of the plugin. Parameters to plugins can be passed
+through the feed options. See :ref:`feed options <feed-options>` for examples.
+
+.. _builtin-plugins:
+
+Built-in Plugins
+----------------
+
+.. autoclass:: scrapy.extensions.postprocessing.GzipPlugin
+
+.. autoclass:: scrapy.extensions.postprocessing.LZMAPlugin
+
+.. autoclass:: scrapy.extensions.postprocessing.Bz2Plugin
+
+.. _custom-plugins:
+
+Custom Plugins
+--------------
+
+Each plugin is a class that must implement the following methods:
+
+.. method:: __init__(self, file, feed_options)
+
+    Initialize the plugin.
+
+    :param file: file-like object having at least the `write`, `tell` and `close` methods implemented
+
+    :param feed_options: feed-specific :ref:`options <feed-options>`
+    :type feed_options: :class:`dict`
+
+.. method:: write(self, data)
+
+   Process and write `data` (:class:`bytes` or :class:`memoryview`) into the plugin's target file.
+   It must return number of bytes written.
+
+.. method:: close(self)
+
+    Close the target file object.
+
+To pass a parameter to your plugin, use :ref:`feed options <feed-options>`. You
+can then access those parameters from the ``__init__`` method of your plugin.
+
+
 Settings
 ========
 
 These are the settings used for configuring the feed exports:
 
- * :setting:`FEEDS` (mandatory)
- * :setting:`FEED_EXPORT_ENCODING`
- * :setting:`FEED_STORE_EMPTY`
- * :setting:`FEED_EXPORT_FIELDS`
- * :setting:`FEED_EXPORT_INDENT`
- * :setting:`FEED_STORAGES`
- * :setting:`FEED_STORAGE_FTP_ACTIVE`
- * :setting:`FEED_STORAGE_S3_ACL`
- * :setting:`FEED_EXPORTERS`
- * :setting:`FEED_EXPORT_BATCH_ITEM_COUNT`
+-   :setting:`FEEDS` (mandatory)
+-   :setting:`FEED_EXPORT_ENCODING`
+-   :setting:`FEED_STORE_EMPTY`
+-   :setting:`FEED_EXPORT_FIELDS`
+-   :setting:`FEED_EXPORT_INDENT`
+-   :setting:`FEED_STORAGES`
+-   :setting:`FEED_STORAGE_FTP_ACTIVE`
+-   :setting:`FEED_STORAGE_S3_ACL`
+-   :setting:`FEED_EXPORTERS`
+-   :setting:`FEED_EXPORT_BATCH_ITEM_COUNT`
 
 .. currentmodule:: scrapy.extensions.feedexport
 
@@ -301,24 +438,31 @@ For instance::
             'format': 'json',
             'encoding': 'utf8',
             'store_empty': False,
+            'item_classes': [MyItemClass1, 'myproject.items.MyItemClass2'],
             'fields': None,
             'indent': 4,
             'item_export_kwargs': {
                'export_empty_fields': True,
             },
-        }, 
+        },
         '/home/user/documents/items.xml': {
             'format': 'xml',
             'fields': ['name', 'price'],
+            'item_filter': MyCustomFilter1,
             'encoding': 'latin1',
             'indent': 8,
         },
-        pathlib.Path('items.csv'): {
+        pathlib.Path('items.csv.gz'): {
             'format': 'csv',
             'fields': ['price', 'name'],
+            'item_filter': 'myproject.filters.MyCustomFilter2',
+            'postprocessing': [MyPlugin1, 'scrapy.extensions.postprocessing.GzipPlugin'],
+            'gzip_compresslevel': 5,
         },
     }
 
+.. _feed-options:
+
 The following is a list of the accepted keys and the setting that is used
 as a fallback value if that key is not provided for a specific feed definition:
 
@@ -329,14 +473,30 @@ as a fallback value if that key is not provided for a specific feed definition:
 -   ``batch_item_count``: falls back to
     :setting:`FEED_EXPORT_BATCH_ITEM_COUNT`.
 
+    .. versionadded:: 2.3.0
+
 -   ``encoding``: falls back to :setting:`FEED_EXPORT_ENCODING`.
 
 -   ``fields``: falls back to :setting:`FEED_EXPORT_FIELDS`.
 
+-   ``item_classes``: list of :ref:`item classes <topics-items>` to export.
+
+    If undefined or empty, all items are exported.
+
+    .. versionadded:: 2.6.0
+
+-   ``item_filter``: a :ref:`filter class <item-filter>` to filter items to export.
+
+    :class:`~scrapy.extensions.feedexport.ItemFilter` is used be default.
+
+    .. versionadded:: 2.6.0
+
 -   ``indent``: falls back to :setting:`FEED_EXPORT_INDENT`.
 
 -   ``item_export_kwargs``: :class:`dict` with keyword arguments for the corresponding :ref:`item exporter class <topics-exporters>`.
 
+    .. versionadded:: 2.4.0
+
 -   ``overwrite``: whether to overwrite the file if it already exists
     (``True``) or append to its content (``False``).
 
@@ -353,12 +513,21 @@ as a fallback value if that key is not provided for a specific feed definition:
     -   :ref:`topics-feed-storage-s3`: ``True`` (appending `is not supported
         <https://forums.aws.amazon.com/message.jspa?messageID=540395>`_)
 
+    -   :ref:`topics-feed-storage-gcs`: ``True`` (appending is not supported)
+
     -   :ref:`topics-feed-storage-stdout`: ``False`` (overwriting is not supported)
 
+    .. versionadded:: 2.4.0
+
 -   ``store_empty``: falls back to :setting:`FEED_STORE_EMPTY`.
 
 -   ``uri_params``: falls back to :setting:`FEED_URI_PARAMS`.
 
+-   ``postprocessing``: list of :ref:`plugins <post-processing>` to use for post-processing.
+
+    The plugins will be used in the order of the list passed.
+
+    .. versionadded:: 2.6.0
 
 .. setting:: FEED_EXPORT_ENCODING
 
@@ -374,6 +543,10 @@ which uses safe numeric encoding (``\uXXXX`` sequences) for historic reasons.
 
 Use ``utf-8`` if you want UTF-8 for JSON too.
 
+.. versionchanged:: 2.8
+   The :command:`startproject` command now sets this setting to
+   ``utf-8`` in the generated ``settings.py`` file.
+
 .. setting:: FEED_EXPORT_FIELDS
 
 FEED_EXPORT_FIELDS
@@ -381,18 +554,9 @@ FEED_EXPORT_FIELDS
 
 Default: ``None``
 
-A list of fields to export, optional.
-Example: ``FEED_EXPORT_FIELDS = ["foo", "bar", "baz"]``.
-
-Use FEED_EXPORT_FIELDS option to define fields to export and their order.
-
-When FEED_EXPORT_FIELDS is empty or None (default), Scrapy uses the fields
-defined in :ref:`item objects <topics-items>` yielded by your spider.
-
-If an exporter requires a fixed set of fields (this is the case for
-:ref:`CSV <topics-feed-format-csv>` export format) and FEED_EXPORT_FIELDS
-is empty or None, then Scrapy tries to infer field names from the
-exported data - currently it uses field names from the first item.
+Use the ``FEED_EXPORT_FIELDS`` setting to define the fields to export, their
+order and their output names. See :attr:`BaseItemExporter.fields_to_export
+<scrapy.exporters.BaseItemExporter.fields_to_export>` for more information.
 
 .. setting:: FEED_EXPORT_INDENT
 
@@ -415,9 +579,12 @@ to ``.json`` or ``.xml``.
 FEED_STORE_EMPTY
 ----------------
 
-Default: ``False``
+Default: ``True``
 
 Whether to export empty feeds (i.e. feeds with no items).
+If ``False``, and there are no items to export, no new files are created and 
+existing files are not modified, even if the :ref:`overwrite feed option 
+<feed-options>` is enabled.
 
 .. setting:: FEED_STORAGES
 
@@ -458,23 +625,27 @@ For a complete list of available values, access the `Canned ACL`_ section on Ama
 FEED_STORAGES_BASE
 ------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        '': 'scrapy.extensions.feedexport.FileFeedStorage',
-        'file': 'scrapy.extensions.feedexport.FileFeedStorage',
-        'stdout': 'scrapy.extensions.feedexport.StdoutFeedStorage',
-        's3': 'scrapy.extensions.feedexport.S3FeedStorage',
-        'ftp': 'scrapy.extensions.feedexport.FTPFeedStorage',
+        "": "scrapy.extensions.feedexport.FileFeedStorage",
+        "file": "scrapy.extensions.feedexport.FileFeedStorage",
+        "stdout": "scrapy.extensions.feedexport.StdoutFeedStorage",
+        "s3": "scrapy.extensions.feedexport.S3FeedStorage",
+        "ftp": "scrapy.extensions.feedexport.FTPFeedStorage",
     }
 
 A dict containing the built-in feed storage backends supported by Scrapy. You
 can disable any of these backends by assigning ``None`` to their URI scheme in
 :setting:`FEED_STORAGES`. E.g., to disable the built-in FTP storage backend
-(without replacement), place this in your ``settings.py``::
+(without replacement), place this in your ``settings.py``:
+
+.. code-block:: python
 
     FEED_STORAGES = {
-        'ftp': None,
+        "ftp": None,
     }
 
 .. setting:: FEED_EXPORTERS
@@ -492,32 +663,39 @@ serialization formats and the values are paths to :ref:`Item exporter
 
 FEED_EXPORTERS_BASE
 -------------------
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'json': 'scrapy.exporters.JsonItemExporter',
-        'jsonlines': 'scrapy.exporters.JsonLinesItemExporter',
-        'jl': 'scrapy.exporters.JsonLinesItemExporter',
-        'csv': 'scrapy.exporters.CsvItemExporter',
-        'xml': 'scrapy.exporters.XmlItemExporter',
-        'marshal': 'scrapy.exporters.MarshalItemExporter',
-        'pickle': 'scrapy.exporters.PickleItemExporter',
+        "json": "scrapy.exporters.JsonItemExporter",
+        "jsonlines": "scrapy.exporters.JsonLinesItemExporter",
+        "jsonl": "scrapy.exporters.JsonLinesItemExporter",
+        "jl": "scrapy.exporters.JsonLinesItemExporter",
+        "csv": "scrapy.exporters.CsvItemExporter",
+        "xml": "scrapy.exporters.XmlItemExporter",
+        "marshal": "scrapy.exporters.MarshalItemExporter",
+        "pickle": "scrapy.exporters.PickleItemExporter",
     }
 
 A dict containing the built-in feed exporters supported by Scrapy. You can
 disable any of these exporters by assigning ``None`` to their serialization
 format in :setting:`FEED_EXPORTERS`. E.g., to disable the built-in CSV exporter
-(without replacement), place this in your ``settings.py``::
+(without replacement), place this in your ``settings.py``:
+
+.. code-block:: python
 
     FEED_EXPORTERS = {
-        'csv': None,
+        "csv": None,
     }
 
 
 .. setting:: FEED_EXPORT_BATCH_ITEM_COUNT
 
 FEED_EXPORT_BATCH_ITEM_COUNT
------------------------------
+----------------------------
+
+.. versionadded:: 2.3.0
 
 Default: ``0``
 
@@ -538,7 +716,9 @@ generated:
   number by introducing leading zeroes as needed, use ``%(batch_id)05d``
   (e.g. ``3`` becomes ``00003``, ``123`` becomes ``00123``).
 
-For instance, if your settings include::
+For instance, if your settings include:
+
+.. code-block:: python
 
     FEED_EXPORT_BATCH_ITEM_COUNT = 100
 
@@ -586,38 +766,49 @@ The function signature should be as follows:
             If :setting:`FEED_EXPORT_BATCH_ITEM_COUNT` is ``0``, ``batch_id``
             is always ``1``.
 
+            .. versionadded:: 2.3.0
+
         -   ``batch_time``: UTC date and time, in ISO format with ``:``
             replaced with ``-``.
 
             See :setting:`FEED_EXPORT_BATCH_ITEM_COUNT`.
 
+            .. versionadded:: 2.3.0
+
         -   ``time``: ``batch_time``, with microseconds set to ``0``.
    :type params: dict
 
    :param spider: source spider of the feed items
-   :type spider: scrapy.spiders.Spider
+   :type spider: scrapy.Spider
 
-For example, to include the :attr:`name <scrapy.spiders.Spider.name>` of the
+   .. caution:: The function should return a new dictionary, modifying
+                the received ``params`` in-place is deprecated.
+
+For example, to include the :attr:`name <scrapy.Spider.name>` of the
 source spider in the feed URI:
 
-#.  Define the following function somewhere in your project::
+#.  Define the following function somewhere in your project:
+
+    .. code-block:: python
 
         # myproject/utils.py
         def uri_params(params, spider):
-            return {**params, 'spider_name': spider.name}
+            return {**params, "spider_name": spider.name}
 
-#.  Point :setting:`FEED_URI_PARAMS` to that function in your settings::
+#.  Point :setting:`FEED_URI_PARAMS` to that function in your settings:
+
+    .. code-block:: python
 
         # myproject/settings.py
-        FEED_URI_PARAMS = 'myproject.utils.uri_params'
+        FEED_URI_PARAMS = "myproject.utils.uri_params"
 
 #.  Use ``%(spider_name)s`` in your feed URI::
 
-        scrapy crawl <spider_name> -o "%(spider_name)s.jl"
+        scrapy crawl <spider_name> -o "%(spider_name)s.jsonl"
 
 
 .. _URIs: https://en.wikipedia.org/wiki/Uniform_Resource_Identifier
 .. _Amazon S3: https://aws.amazon.com/s3/
-.. _botocore: https://github.com/boto/botocore
+.. _boto3: https://github.com/boto/boto3
 .. _Canned ACL: https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl
 .. _Google Cloud Storage: https://cloud.google.com/storage/

docs/topics/item-pipeline.rst

@@ -42,7 +42,7 @@ Each item pipeline component is a Python class that must implement the following
    :type item: :ref:`item object <item-types>`
 
    :param spider: the spider which scraped the item
-   :type spider: :class:`~scrapy.spiders.Spider` object
+   :type spider: :class:`~scrapy.Spider` object
 
 Additionally, they may also implement the following methods:
 
@@ -51,18 +51,18 @@ Additionally, they may also implement the following methods:
    This method is called when the spider is opened.
 
    :param spider: the spider which was opened
-   :type spider: :class:`~scrapy.spiders.Spider` object
+   :type spider: :class:`~scrapy.Spider` object
 
 .. method:: close_spider(self, spider)
 
    This method is called when the spider is closed.
 
    :param spider: the spider which was closed
-   :type spider: :class:`~scrapy.spiders.Spider` object
+   :type spider: :class:`~scrapy.Spider` object
 
-.. method:: from_crawler(cls, crawler)
+.. classmethod:: from_crawler(cls, crawler)
 
-   If present, this classmethod is called to create a pipeline instance
+   If present, this class method is called to create a pipeline instance
    from a :class:`~scrapy.crawler.Crawler`. It must return a new instance
    of the pipeline. Crawler object provides access to all Scrapy core
    components like settings and signals; it is a way for pipeline to
@@ -81,39 +81,44 @@ Price validation and dropping items with no prices
 Let's take a look at the following hypothetical pipeline that adjusts the
 ``price`` attribute for those items that do not include VAT
 (``price_excludes_vat`` attribute), and drops those items which don't
-contain a price::
+contain a price:
+
+.. code-block:: python
 
     from itemadapter import ItemAdapter
     from scrapy.exceptions import DropItem
-    class PricePipeline:
 
+
+    class PricePipeline:
         vat_factor = 1.15
 
         def process_item(self, item, spider):
             adapter = ItemAdapter(item)
-            if adapter.get('price'):
-                if adapter.get('price_excludes_vat'):
-                    adapter['price'] = adapter['price'] * self.vat_factor
+            if adapter.get("price"):
+                if adapter.get("price_excludes_vat"):
+                    adapter["price"] = adapter["price"] * self.vat_factor
                 return item
             else:
                 raise DropItem(f"Missing price in {item}")
 
 
-Write items to a JSON file
---------------------------
+Write items to a JSON lines file
+--------------------------------
 
 The following pipeline stores all scraped items (from all spiders) into a
-single ``items.jl`` file, containing one item per line serialized in JSON
-format::
+single ``items.jsonl`` file, containing one item per line serialized in JSON
+format:
+
+.. code-block:: python
 
    import json
 
    from itemadapter import ItemAdapter
 
-   class JsonWriterPipeline:
 
+   class JsonWriterPipeline:
        def open_spider(self, spider):
-           self.file = open('items.jl', 'w')
+           self.file = open("items.jsonl", "w")
 
        def close_spider(self, spider):
            self.file.close()
@@ -135,14 +140,17 @@ MongoDB address and database name are specified in Scrapy settings;
 MongoDB collection is named after item class.
 
 The main point of this example is to show how to use :meth:`from_crawler`
-method and how to clean up the resources properly.::
+method and how to clean up the resources properly.
+
+.. skip: next
+.. code-block:: python
 
     import pymongo
     from itemadapter import ItemAdapter
 
-    class MongoPipeline:
 
-        collection_name = 'scrapy_items'
+    class MongoPipeline:
+        collection_name = "scrapy_items"
 
         def __init__(self, mongo_uri, mongo_db):
             self.mongo_uri = mongo_uri
@@ -151,8 +159,8 @@ method and how to clean up the resources properly.::
         @classmethod
         def from_crawler(cls, crawler):
             return cls(
-                mongo_uri=crawler.settings.get('MONGO_URI'),
-                mongo_db=crawler.settings.get('MONGO_DATABASE', 'items')
+                mongo_uri=crawler.settings.get("MONGO_URI"),
+                mongo_db=crawler.settings.get("MONGO_DATABASE", "items"),
             )
 
         def open_spider(self, spider):
@@ -183,13 +191,17 @@ render a screenshot of the item URL. After the request response is downloaded,
 the item pipeline saves the screenshot to a file and adds the filename to the
 item.
 
-::
+.. code-block:: python
 
     import hashlib
+    from pathlib import Path
     from urllib.parse import quote
 
     import scrapy
     from itemadapter import ItemAdapter
+    from scrapy.http.request import NO_CALLBACK
+    from scrapy.utils.defer import maybe_deferred_to_future
+
 
     class ScreenshotPipeline:
         """Pipeline that uses Splash to render screenshot of
@@ -201,8 +213,10 @@ item.
             adapter = ItemAdapter(item)
             encoded_item_url = quote(adapter["url"])
             screenshot_url = self.SPLASH_URL.format(encoded_item_url)
-            request = scrapy.Request(screenshot_url)
-            response = await spider.crawler.engine.download(request, spider)
+            request = scrapy.Request(screenshot_url, callback=NO_CALLBACK)
+            response = await maybe_deferred_to_future(
+                spider.crawler.engine.download(request)
+            )
 
             if response.status != 200:
                 # Error happened, return item.
@@ -212,8 +226,7 @@ item.
             url = adapter["url"]
             url_hash = hashlib.md5(url.encode("utf8")).hexdigest()
             filename = f"{url_hash}.png"
-            with open(filename, "wb") as f:
-                f.write(response.body)
+            Path(filename).write_bytes(response.body)
 
             # Store filename in item.
             adapter["screenshot_filename"] = filename
@@ -226,23 +239,24 @@ Duplicates filter
 
 A filter that looks for duplicate items, and drops those items that were
 already processed. Let's say that our items have a unique id, but our spider
-returns multiples items with the same id::
+returns multiples items with the same id:
 
+.. code-block:: python
 
     from itemadapter import ItemAdapter
     from scrapy.exceptions import DropItem
 
-    class DuplicatesPipeline:
 
+    class DuplicatesPipeline:
         def __init__(self):
             self.ids_seen = set()
 
         def process_item(self, item, spider):
             adapter = ItemAdapter(item)
-            if adapter['id'] in self.ids_seen:
+            if adapter["id"] in self.ids_seen:
                 raise DropItem(f"Duplicate item found: {item!r}")
             else:
-                self.ids_seen.add(adapter['id'])
+                self.ids_seen.add(adapter["id"])
                 return item
 
 
@@ -250,11 +264,13 @@ Activating an Item Pipeline component
 =====================================
 
 To activate an Item Pipeline component you must add its class to the
-:setting:`ITEM_PIPELINES` setting, like in the following example::
+:setting:`ITEM_PIPELINES` setting, like in the following example:
+
+.. code-block:: python
 
    ITEM_PIPELINES = {
-       'myproject.pipelines.PricePipeline': 300,
-       'myproject.pipelines.JsonWriterPipeline': 800,
+       "myproject.pipelines.PricePipeline": 300,
+       "myproject.pipelines.JsonWriterPipeline": 800,
    }
 
 The integer values you assign to classes in this setting determine the

docs/topics/items.rst

@@ -42,7 +42,8 @@ Item objects
 :class:`Item` provides a :class:`dict`-like API plus additional features that
 make it the most feature-complete item type:
 
-.. class:: Item([arg])
+.. class:: scrapy.item.Item([arg])
+.. class:: scrapy.Item([arg])
 
     :class:`Item` objects replicate the standard :class:`dict` API, including
     its ``__init__`` method.
@@ -75,10 +76,13 @@ make it the most feature-complete item type:
         :class:`Field` objects used in the :ref:`Item declaration
         <topics-items-declaring>`.
 
-Example::
+Example:
+
+.. code-block:: python
 
     from scrapy.item import Item, Field
 
+
     class CustomItem(Item):
         one_field = Field()
         another_field = Field()
@@ -101,15 +105,13 @@ Additionally, ``dataclass`` items also allow to:
 * define custom field metadata through :func:`dataclasses.field`, which can be used to
   :ref:`customize serialization <topics-exporters-field-serialization>`.
 
-They work natively in Python 3.7 or later, or using the `dataclasses
-backport`_ in Python 3.6.
+Example:
 
-.. _dataclasses backport: https://pypi.org/project/dataclasses/
-
-Example::
+.. code-block:: python
 
     from dataclasses import dataclass
 
+
     @dataclass
     class CustomItem:
         one_field: str
@@ -137,10 +139,13 @@ Additionally, ``attr.s`` items also allow to:
 
 In order to use this type, the :doc:`attrs package <attrs:index>` needs to be installed.
 
-Example::
+Example:
+
+.. code-block:: python
 
     import attr
 
+
     @attr.s
     class CustomItem:
         one_field = attr.ib()
@@ -156,10 +161,13 @@ Declaring Item subclasses
 -------------------------
 
 Item subclasses are declared using a simple class definition syntax and
-:class:`Field` objects. Here is an example::
+:class:`Field` objects. Here is an example:
+
+.. code-block:: python
 
     import scrapy
 
+
     class Product(scrapy.Item):
         name = scrapy.Field()
         price = scrapy.Field()
@@ -199,7 +207,8 @@ It's important to note that the :class:`Field` objects used to declare the item
 do not stay assigned as class attributes. Instead, they can be accessed through
 the :attr:`Item.fields` attribute.
 
-.. class:: Field([arg])
+.. class:: scrapy.item.Field([arg])
+.. class:: scrapy.Field([arg])
 
     The :class:`Field` class is just an alias to the built-in :class:`dict` class and
     doesn't provide any extra functionality or attributes. In other words,
@@ -225,62 +234,68 @@ notice the API is very similar to the :class:`dict` API.
 Creating items
 ''''''''''''''
 
->>> product = Product(name='Desktop PC', price=1000)
->>> print(product)
-Product(name='Desktop PC', price=1000)
+.. code-block:: pycon
+
+    >>> product = Product(name="Desktop PC", price=1000)
+    >>> print(product)
+    Product(name='Desktop PC', price=1000)
 
 
 Getting field values
 ''''''''''''''''''''
 
->>> product['name']
-Desktop PC
->>> product.get('name')
-Desktop PC
+.. code-block:: pycon
 
->>> product['price']
-1000
+    >>> product["name"]
+    Desktop PC
+    >>> product.get("name")
+    Desktop PC
 
->>> product['last_updated']
-Traceback (most recent call last):
-    ...
-KeyError: 'last_updated'
+    >>> product["price"]
+    1000
 
->>> product.get('last_updated', 'not set')
-not set
+    >>> product["last_updated"]
+    Traceback (most recent call last):
+        ...
+    KeyError: 'last_updated'
 
->>> product['lala'] # getting unknown field
-Traceback (most recent call last):
-    ...
-KeyError: 'lala'
+    >>> product.get("last_updated", "not set")
+    not set
 
->>> product.get('lala', 'unknown field')
-'unknown field'
+    >>> product["lala"]  # getting unknown field
+    Traceback (most recent call last):
+        ...
+    KeyError: 'lala'
 
->>> 'name' in product  # is name field populated?
-True
+    >>> product.get("lala", "unknown field")
+    'unknown field'
 
->>> 'last_updated' in product  # is last_updated populated?
-False
+    >>> "name" in product  # is name field populated?
+    True
 
->>> 'last_updated' in product.fields  # is last_updated a declared field?
-True
+    >>> "last_updated" in product  # is last_updated populated?
+    False
 
->>> 'lala' in product.fields  # is lala a declared field?
-False
+    >>> "last_updated" in product.fields  # is last_updated a declared field?
+    True
+
+    >>> "lala" in product.fields  # is lala a declared field?
+    False
 
 
 Setting field values
 ''''''''''''''''''''
 
->>> product['last_updated'] = 'today'
->>> product['last_updated']
-today
+.. code-block:: pycon
 
->>> product['lala'] = 'test' # setting unknown field
-Traceback (most recent call last):
-    ...
-KeyError: 'Product does not support field: lala'
+    >>> product["last_updated"] = "today"
+    >>> product["last_updated"]
+    today
+
+    >>> product["lala"] = "test"  # setting unknown field
+    Traceback (most recent call last):
+        ...
+    KeyError: 'Product does not support field: lala'
 
 
 Accessing all populated values
@@ -288,11 +303,13 @@ Accessing all populated values
 
 To access all populated values, just use the typical :class:`dict` API:
 
->>> product.keys()
-['price', 'name']
+.. code-block:: pycon
 
->>> product.items()
-[('price', 1000), ('name', 'Desktop PC')]
+    >>> product.keys()
+    ['price', 'name']
+
+    >>> product.items()
+    [('price', 1000), ('name', 'Desktop PC')]
 
 
 .. _copying-items:
@@ -317,11 +334,11 @@ If that is not the desired behavior, use a deep copy instead.
 See :mod:`copy` for more information.
 
 To create a shallow copy of an item, you can either call
-:meth:`~scrapy.item.Item.copy` on an existing item
+:meth:`~scrapy.Item.copy` on an existing item
 (``product2 = product.copy()``) or instantiate your item class from an existing
 item (``product2 = Product(product)``).
 
-To create a deep copy, call :meth:`~scrapy.item.Item.deepcopy` instead
+To create a deep copy, call :meth:`~scrapy.Item.deepcopy` instead
 (``product2 = product.deepcopy()``).
 
 
@@ -330,18 +347,20 @@ Other common tasks
 
 Creating dicts from items:
 
->>> dict(product) # create a dict from all populated values
-{'price': 1000, 'name': 'Desktop PC'}
+.. code-block:: pycon
 
-Creating items from dicts:
+    >>> dict(product)  # create a dict from all populated values
+    {'price': 1000, 'name': 'Desktop PC'}
 
->>> Product({'name': 'Laptop PC', 'price': 1500})
-Product(price=1500, name='Laptop PC')
+    Creating items from dicts:
 
->>> Product({'name': 'Laptop PC', 'lala': 1500}) # warning: unknown field in dict
-Traceback (most recent call last):
-    ...
-KeyError: 'Product does not support field: lala'
+    >>> Product({"name": "Laptop PC", "price": 1500})
+    Product(price=1500, name='Laptop PC')
+
+    >>> Product({"name": "Laptop PC", "lala": 1500})  # warning: unknown field in dict
+    Traceback (most recent call last):
+        ...
+    KeyError: 'Product does not support field: lala'
 
 
 Extending Item subclasses
@@ -350,17 +369,21 @@ Extending Item subclasses
 You can extend Items (to add more fields or to change some metadata for some
 fields) by declaring a subclass of your original Item.
 
-For example::
+For example:
+
+.. code-block:: python
 
     class DiscountedProduct(Product):
         discount_percent = scrapy.Field(serializer=str)
         discount_expiration_date = scrapy.Field()
 
 You can also extend field metadata by using the previous field metadata and
-appending more values, or changing existing values, like this::
+appending more values, or changing existing values, like this:
+
+.. code-block:: python
 
     class SpecificProduct(Product):
-        name = scrapy.Field(Product.fields['name'], serializer=my_serializer)
+        name = scrapy.Field(Product.fields["name"], serializer=my_serializer)
 
 That adds (or replaces) the ``serializer`` metadata key for the ``name`` field,
 keeping all the previously existing metadata values.

docs/topics/jobs.rst

@@ -39,6 +39,8 @@ a signal), and resume it later by issuing the same command::
 
     scrapy crawl somespider -s JOBDIR=crawls/somespider-1
 
+.. _topics-keeping-persistent-state-between-batches:
+
 Keeping persistent state between batches
 ========================================
 
@@ -49,11 +51,13 @@ loading that attribute from the job directory, when the spider starts and
 stops.
 
 Here's an example of a callback that uses the spider state (other spider code
-is omitted for brevity)::
+is omitted for brevity):
+
+.. code-block:: python
 
     def parse_item(self, response):
         # parse item here
-        self.state['items_count'] = self.state.get('items_count', 0) + 1
+        self.state["items_count"] = self.state.get("items_count", 0) + 1
 
 Persistence gotchas
 ===================
@@ -74,10 +78,10 @@ on cookies.
 Request serialization
 ---------------------
 
-For persistence to work, :class:`~scrapy.http.Request` objects must be
+For persistence to work, :class:`~scrapy.Request` objects must be
 serializable with :mod:`pickle`, except for the ``callback`` and ``errback``
 values passed to their ``__init__`` method, which must be methods of the
-running :class:`~scrapy.spiders.Spider` class.
+running :class:`~scrapy.Spider` class.
 
 If you wish to log the requests that couldn't be serialized, you can set the
 :setting:`SCHEDULER_DEBUG` setting to ``True`` in the project's settings page.

docs/topics/leaks.rst

@@ -27,7 +27,7 @@ Common causes of memory leaks
 
 It happens quite often (sometimes by accident, sometimes on purpose) that the
 Scrapy developer passes objects referenced in Requests (for example, using the
-:attr:`~scrapy.http.Request.cb_kwargs` or :attr:`~scrapy.http.Request.meta`
+:attr:`~scrapy.Request.cb_kwargs` or :attr:`~scrapy.Request.meta`
 attributes or the request callback function) and that effectively bounds the
 lifetime of those referenced objects to the lifetime of the Request. This is,
 by far, the most common cause of memory leaks in Scrapy projects, and a quite
@@ -48,9 +48,9 @@ Too Many Requests?
 ------------------
 
 By default Scrapy keeps the request queue in memory; it includes
-:class:`~scrapy.http.Request` objects and all objects
-referenced in Request attributes (e.g. in :attr:`~scrapy.http.Request.cb_kwargs`
-and :attr:`~scrapy.http.Request.meta`).
+:class:`~scrapy.Request` objects and all objects
+referenced in Request attributes (e.g. in :attr:`~scrapy.Request.cb_kwargs`
+and :attr:`~scrapy.Request.meta`).
 While not necessarily a leak, this can take a lot of memory. Enabling
 :ref:`persistent job queue <topics-jobs>` could help keeping memory usage
 in control.
@@ -70,13 +70,15 @@ alias to the :func:`~scrapy.utils.trackref.print_live_refs` function::
 
     telnet localhost 6023
 
-    >>> prefs()
-    Live References
+    .. code-block:: pycon
 
-    ExampleSpider                       1   oldest: 15s ago
-    HtmlResponse                       10   oldest: 1s ago
-    Selector                            2   oldest: 0s ago
-    FormRequest                       878   oldest: 7s ago
+        >>> prefs()
+        Live References
+
+        ExampleSpider                       1   oldest: 15s ago
+        HtmlResponse                       10   oldest: 1s ago
+        Selector                            2   oldest: 0s ago
+        FormRequest                       878   oldest: 7s ago
 
 As you can see, that report also shows the "age" of the oldest object in each
 class. If you're running multiple spiders per process chances are you can
@@ -90,11 +92,11 @@ Which objects are tracked?
 The objects tracked by ``trackrefs`` are all from these classes (and all its
 subclasses):
 
-* :class:`scrapy.http.Request`
+* :class:`scrapy.Request`
 * :class:`scrapy.http.Response`
-* :class:`scrapy.item.Item`
-* :class:`scrapy.selector.Selector`
-* :class:`scrapy.spiders.Spider`
+* :class:`scrapy.Item`
+* :class:`scrapy.Selector`
+* :class:`scrapy.Spider`
 
 A real example
 --------------
@@ -114,7 +116,9 @@ a priori, of course) by using the ``trackref`` tool.
 
 After the crawler is running for a few minutes and we notice its memory usage
 has grown a lot, we can enter its telnet console and check the live
-references::
+references:
+
+.. code-block:: pycon
 
     >>> prefs()
     Live References
@@ -134,19 +138,23 @@ generating the leaks (passing response references inside requests).
 Sometimes extra information about live objects can be helpful.
 Let's check the oldest response:
 
->>> from scrapy.utils.trackref import get_oldest
->>> r = get_oldest('HtmlResponse')
->>> r.url
-'http://www.somenastyspider.com/product.php?pid=123'
+.. code-block:: pycon
+
+    >>> from scrapy.utils.trackref import get_oldest
+    >>> r = get_oldest("HtmlResponse")
+    >>> r.url
+    'http://www.somenastyspider.com/product.php?pid=123'
 
 If you want to iterate over all objects, instead of getting the oldest one, you
 can use the :func:`scrapy.utils.trackref.iter_all` function:
 
->>> from scrapy.utils.trackref import iter_all
->>> [r.url for r in iter_all('HtmlResponse')]
-['http://www.somenastyspider.com/product.php?pid=123',
- 'http://www.somenastyspider.com/product.php?pid=584',
-...]
+.. code-block:: pycon
+
+    >>> from scrapy.utils.trackref import iter_all
+    >>> [r.url for r in iter_all("HtmlResponse")]
+    ['http://www.somenastyspider.com/product.php?pid=123',
+    'http://www.somenastyspider.com/product.php?pid=584',
+    ...]
 
 Too many spiders?
 -----------------
@@ -154,11 +162,13 @@ Too many spiders?
 If your project has too many spiders executed in parallel,
 the output of :func:`prefs()` can be difficult to read.
 For this reason, that function has a ``ignore`` argument which can be used to
-ignore a particular class (and all its subclases). For
+ignore a particular class (and all its subclasses). For
 example, this won't show any live references to spiders:
 
->>> from scrapy.spiders import Spider
->>> prefs(ignore=Spider)
+.. code-block:: pycon
+
+    >>> from scrapy.spiders import Spider
+    >>> prefs(ignore=Spider)
 
 .. module:: scrapy.utils.trackref
    :synopsis: Track references of live objects
@@ -216,30 +226,32 @@ If you use ``pip``, you can install muppy with the following command::
 Here's an example to view all Python objects available in
 the heap using muppy:
 
->>> from pympler import muppy
->>> all_objects = muppy.get_objects()
->>> len(all_objects)
-28667
->>> from pympler import summary
->>> suml = summary.summarize(all_objects)
->>> summary.print_(suml)
-                               types |   # objects |   total size
-==================================== | =========== | ============
-                         <class 'str |        9822 |      1.10 MB
-                        <class 'dict |        1658 |    856.62 KB
-                        <class 'type |         436 |    443.60 KB
-                        <class 'code |        2974 |    419.56 KB
-          <class '_io.BufferedWriter |           2 |    256.34 KB
-                         <class 'set |         420 |    159.88 KB
-          <class '_io.BufferedReader |           1 |    128.17 KB
-          <class 'wrapper_descriptor |        1130 |     88.28 KB
-                       <class 'tuple |        1304 |     86.57 KB
-                     <class 'weakref |        1013 |     79.14 KB
-  <class 'builtin_function_or_method |         958 |     67.36 KB
-           <class 'method_descriptor |         865 |     60.82 KB
-                 <class 'abc.ABCMeta |          62 |     59.96 KB
-                        <class 'list |         446 |     58.52 KB
-                         <class 'int |        1425 |     43.20 KB
+.. code-block:: pycon
+
+    >>> from pympler import muppy
+    >>> all_objects = muppy.get_objects()
+    >>> len(all_objects)
+    28667
+    >>> from pympler import summary
+    >>> suml = summary.summarize(all_objects)
+    >>> summary.print_(suml)
+                                   types |   # objects |   total size
+    ==================================== | =========== | ============
+                             <class 'str |        9822 |      1.10 MB
+                            <class 'dict |        1658 |    856.62 KB
+                            <class 'type |         436 |    443.60 KB
+                            <class 'code |        2974 |    419.56 KB
+              <class '_io.BufferedWriter |           2 |    256.34 KB
+                             <class 'set |         420 |    159.88 KB
+              <class '_io.BufferedReader |           1 |    128.17 KB
+              <class 'wrapper_descriptor |        1130 |     88.28 KB
+                           <class 'tuple |        1304 |     86.57 KB
+                         <class 'weakref |        1013 |     79.14 KB
+      <class 'builtin_function_or_method |         958 |     67.36 KB
+               <class 'method_descriptor |         865 |     60.82 KB
+                     <class 'abc.ABCMeta |          62 |     59.96 KB
+                            <class 'list |         446 |     58.52 KB
+                             <class 'int |        1425 |     43.20 KB
 
 For more info about muppy, refer to the `muppy documentation`_.
 

docs/topics/link-extractors.rst

@@ -18,7 +18,9 @@ through a set of :class:`~scrapy.spiders.Rule` objects.
 
 You can also use link extractors in regular spiders. For example, you can instantiate
 :class:`LinkExtractor <scrapy.linkextractors.lxmlhtml.LxmlLinkExtractor>` into a class
-variable in your spider, and use it from your spider callbacks::
+variable in your spider, and use it from your spider callbacks:
+
+.. code-block:: python
 
     def parse(self, response):
         for link in self.link_extractor.extract_links(response):
@@ -132,10 +134,12 @@ LxmlLinkExtractor
 
         .. highlight:: python
 
-        You can use the following function in ``process_value``::
+        You can use the following function in ``process_value``:
+
+        .. code-block:: python
 
             def process_value(value):
-                m = re.search("javascript:goToPage\('(.*?)'", value)
+                m = re.search(r"javascript:goToPage\('(.*?)'", value)
                 if m:
                     return m.group(1)
 

docs/topics/loaders.rst

@@ -46,18 +46,21 @@ using a proper processing function.
 
 Here is a typical Item Loader usage in a :ref:`Spider <topics-spiders>`, using
 the :ref:`Product item <topics-items-declaring>` declared in the :ref:`Items
-chapter <topics-items>`::
+chapter <topics-items>`:
+
+.. code-block:: python
 
     from scrapy.loader import ItemLoader
     from myproject.items import Product
 
+
     def parse(self, response):
         l = ItemLoader(item=Product(), response=response)
-        l.add_xpath('name', '//div[@class="product_name"]')
-        l.add_xpath('name', '//div[@class="product_title"]')
-        l.add_xpath('price', '//p[@id="price"]')
-        l.add_css('stock', 'p#stock]')
-        l.add_value('last_updated', 'today') # you can also use literal values
+        l.add_xpath("name", '//div[@class="product_name"]')
+        l.add_xpath("name", '//div[@class="product_title"]')
+        l.add_xpath("price", '//p[@id="price"]')
+        l.add_css("stock", "p#stock")
+        l.add_value("last_updated", "today")  # you can also use literal values
         return l.load_item()
 
 By quickly looking at that code, we can see the ``name`` field is being
@@ -93,11 +96,14 @@ will be populated incrementally using the loader's :meth:`~ItemLoader.add_xpath`
 :meth:`~ItemLoader.add_css` and :meth:`~ItemLoader.add_value` methods.
 
 One approach to overcome this is to define items using the
-:func:`~dataclasses.field` function, with a ``default`` argument::
+:func:`~dataclasses.field` function, with a ``default`` argument:
+
+.. code-block:: python
 
     from dataclasses import dataclass, field
     from typing import Optional
 
+
     @dataclass
     class InventoryItem:
         name: Optional[str] = field(default=None)
@@ -122,14 +128,16 @@ processor). The result of the output processor is the final value that gets
 assigned to the item.
 
 Let's see an example to illustrate how the input and output processors are
-called for a particular field (the same applies for any other field)::
+called for a particular field (the same applies for any other field):
+
+.. code-block:: python
 
     l = ItemLoader(Product(), some_selector)
-    l.add_xpath('name', xpath1) # (1)
-    l.add_xpath('name', xpath2) # (2)
-    l.add_css('name', css) # (3)
-    l.add_value('name', 'test') # (4)
-    return l.load_item() # (5)
+    l.add_xpath("name", xpath1)  # (1)
+    l.add_xpath("name", xpath2)  # (2)
+    l.add_css("name", css)  # (3)
+    l.add_value("name", "test")  # (4)
+    return l.load_item()  # (5)
 
 So what happens is:
 
@@ -184,13 +192,15 @@ processors <itemloaders:built-in-processors>` built-in for convenience.
 Declaring Item Loaders
 ======================
 
-Item Loaders are declared using a class definition syntax. Here is an example::
+Item Loaders are declared using a class definition syntax. Here is an example:
+
+.. code-block:: python
 
     from itemloaders.processors import TakeFirst, MapCompose, Join
     from scrapy.loader import ItemLoader
 
-    class ProductLoader(ItemLoader):
 
+    class ProductLoader(ItemLoader):
         default_output_processor = TakeFirst()
 
         name_in = MapCompose(str.title)
@@ -215,16 +225,20 @@ As seen in the previous section, input and output processors can be declared in
 the Item Loader definition, and it's very common to declare input processors
 this way. However, there is one more place where you can specify the input and
 output processors to use: in the :ref:`Item Field <topics-items-fields>`
-metadata. Here is an example::
+metadata. Here is an example:
+
+.. code-block:: python
 
     import scrapy
     from itemloaders.processors import Join, MapCompose, TakeFirst
     from w3lib.html import remove_tags
 
+
     def filter_price(value):
         if value.isdigit():
             return value
 
+
     class Product(scrapy.Item):
         name = scrapy.Field(
             input_processor=MapCompose(remove_tags),
@@ -235,12 +249,15 @@ metadata. Here is an example::
             output_processor=TakeFirst(),
         )
 
->>> from scrapy.loader import ItemLoader
->>> il = ItemLoader(item=Product())
->>> il.add_value('name', ['Welcome to my', '<strong>website</strong>'])
->>> il.add_value('price', ['&euro;', '<span>1000</span>'])
->>> il.load_item()
-{'name': 'Welcome to my website', 'price': '1000'}
+
+.. code-block:: pycon
+
+    >>> from scrapy.loader import ItemLoader
+    >>> il = ItemLoader(item=Product())
+    >>> il.add_value("name", ["Welcome to my", "<strong>website</strong>"])
+    >>> il.add_value("price", ["&euro;", "<span>1000</span>"])
+    >>> il.load_item()
+    {'name': 'Welcome to my website', 'price': '1000'}
 
 The precedence order, for both input and output processors, is as follows:
 
@@ -263,10 +280,12 @@ declaring, instantiating or using Item Loader. They are used to modify the
 behaviour of the input/output processors.
 
 For example, suppose you have a function ``parse_length`` which receives a text
-value and extracts a length from it::
+value and extracts a length from it:
+
+.. code-block:: python
 
     def parse_length(text, loader_context):
-        unit = loader_context.get('unit', 'm')
+        unit = loader_context.get("unit", "m")
         # ... length parsing code goes here ...
         return parsed_length
 
@@ -278,22 +297,28 @@ function (``parse_length`` in this case) can thus use them.
 There are several ways to modify Item Loader context values:
 
 1. By modifying the currently active Item Loader context
-   (:attr:`~ItemLoader.context` attribute)::
+   (:attr:`~ItemLoader.context` attribute):
+
+   .. code-block:: python
 
       loader = ItemLoader(product)
-      loader.context['unit'] = 'cm'
+      loader.context["unit"] = "cm"
 
 2. On Item Loader instantiation (the keyword arguments of Item Loader
-   ``__init__`` method are stored in the Item Loader context)::
+   ``__init__`` method are stored in the Item Loader context):
 
-      loader = ItemLoader(product, unit='cm')
+   .. code-block:: python
+
+      loader = ItemLoader(product, unit="cm")
 
 3. On Item Loader declaration, for those input/output processors that support
    instantiating them with an Item Loader context. :class:`~processor.MapCompose` is one of
-   them::
+   them:
+
+   .. code-block:: python
 
        class ProductLoader(ItemLoader):
-           length_out = MapCompose(parse_length, unit='cm')
+           length_out = MapCompose(parse_length, unit="cm")
 
 
 ItemLoader objects
@@ -323,25 +348,29 @@ Example::
 Without nested loaders, you need to specify the full xpath (or css) for each value
 that you wish to extract.
 
-Example::
+Example:
+
+.. code-block:: python
 
     loader = ItemLoader(item=Item())
     # load stuff not in the footer
-    loader.add_xpath('social', '//footer/a[@class = "social"]/@href')
-    loader.add_xpath('email', '//footer/a[@class = "email"]/@href')
+    loader.add_xpath("social", '//footer/a[@class = "social"]/@href')
+    loader.add_xpath("email", '//footer/a[@class = "email"]/@href')
     loader.load_item()
 
 Instead, you can create a nested loader with the footer selector and add values
 relative to the footer.  The functionality is the same but you avoid repeating
 the footer selector.
 
-Example::
+Example:
+
+.. code-block:: python
 
     loader = ItemLoader(item=Item())
     # load stuff not in the footer
-    footer_loader = loader.nested_xpath('//footer')
-    footer_loader.add_xpath('social', 'a[@class = "social"]/@href')
-    footer_loader.add_xpath('email', 'a[@class = "email"]/@href')
+    footer_loader = loader.nested_xpath("//footer")
+    footer_loader.add_xpath("social", 'a[@class = "social"]/@href')
+    footer_loader.add_xpath("email", 'a[@class = "email"]/@href')
     # no need to call footer_loader.load_item()
     loader.load_item()
 
@@ -370,25 +399,32 @@ three dashes (e.g. ``---Plasma TV---``) and you don't want to end up scraping
 those dashes in the final product names.
 
 Here's how you can remove those dashes by reusing and extending the default
-Product Item Loader (``ProductLoader``)::
+Product Item Loader (``ProductLoader``):
+
+.. code-block:: python
 
     from itemloaders.processors import MapCompose
     from myproject.ItemLoaders import ProductLoader
 
+
     def strip_dashes(x):
-        return x.strip('-')
+        return x.strip("-")
+
 
     class SiteSpecificLoader(ProductLoader):
         name_in = MapCompose(strip_dashes, ProductLoader.name_in)
 
 Another case where extending Item Loaders can be very helpful is when you have
 multiple source formats, for example XML and HTML. In the XML version you may
-want to remove ``CDATA`` occurrences. Here's an example of how to do it::
+want to remove ``CDATA`` occurrences. Here's an example of how to do it:
+
+.. code-block:: python
 
     from itemloaders.processors import MapCompose
     from myproject.ItemLoaders import ProductLoader
     from myproject.utils.xml import remove_cdata
 
+
     class XmlProductLoader(ProductLoader):
         name_in = MapCompose(remove_cdata, ProductLoader.name_in)
 

docs/topics/logging.rst

@@ -39,16 +39,22 @@ How to log messages
 ===================
 
 Here's a quick example of how to log a message using the ``logging.WARNING``
-level::
+level:
+
+.. code-block:: python
 
     import logging
+
     logging.warning("This is a warning")
 
 There are shortcuts for issuing log messages on any of the standard 5 levels,
 and there's also a general ``logging.log`` method which takes a given level as
-argument.  If needed, the last example could be rewritten as::
+argument.  If needed, the last example could be rewritten as:
+
+.. code-block:: python
 
     import logging
+
     logging.log(logging.WARNING, "This is a warning")
 
 On top of that, you can create different "loggers" to encapsulate messages. (For
@@ -59,24 +65,33 @@ constructions.
 The previous examples use the root logger behind the scenes, which is a top level
 logger where all messages are propagated to (unless otherwise specified). Using
 ``logging`` helpers is merely a shortcut for getting the root logger
-explicitly, so this is also an equivalent of the last snippets::
+explicitly, so this is also an equivalent of the last snippets:
+
+.. code-block:: python
 
     import logging
+
     logger = logging.getLogger()
     logger.warning("This is a warning")
 
 You can use a different logger just by getting its name with the
-``logging.getLogger`` function::
+``logging.getLogger`` function:
+
+.. code-block:: python
 
     import logging
-    logger = logging.getLogger('mycustomlogger')
+
+    logger = logging.getLogger("mycustomlogger")
     logger.warning("This is a warning")
 
 Finally, you can ensure having a custom logger for any module you're working on
 by using the ``__name__`` variable, which is populated with current module's
-path::
+path:
+
+.. code-block:: python
 
     import logging
+
     logger = logging.getLogger(__name__)
     logger.warning("This is a warning")
 
@@ -93,34 +108,38 @@ path::
 Logging from Spiders
 ====================
 
-Scrapy provides a :data:`~scrapy.spiders.Spider.logger` within each Spider
-instance, which can be accessed and used like this::
+Scrapy provides a :data:`~scrapy.Spider.logger` within each Spider
+instance, which can be accessed and used like this:
+
+.. code-block:: python
 
     import scrapy
 
-    class MySpider(scrapy.Spider):
 
-        name = 'myspider'
-        start_urls = ['https://scrapinghub.com']
+    class MySpider(scrapy.Spider):
+        name = "myspider"
+        start_urls = ["https://scrapy.org"]
 
         def parse(self, response):
-            self.logger.info('Parse function called on %s', response.url)
+            self.logger.info("Parse function called on %s", response.url)
 
 That logger is created using the Spider's name, but you can use any custom
-Python logger you want. For example::
+Python logger you want. For example:
+
+.. code-block:: python
 
     import logging
     import scrapy
 
-    logger = logging.getLogger('mycustomlogger')
+    logger = logging.getLogger("mycustomlogger")
+
 
     class MySpider(scrapy.Spider):
-
-        name = 'myspider'
-        start_urls = ['https://scrapinghub.com']
+        name = "myspider"
+        start_urls = ["https://scrapy.org"]
 
         def parse(self, response):
-            logger.info('Parse function called on %s', response.url)
+            logger.info("Parse function called on %s", response.url)
 
 .. _topics-logging-configuration:
 
@@ -143,6 +162,7 @@ Logging settings
 These settings can be used to configure the logging:
 
 * :setting:`LOG_FILE`
+* :setting:`LOG_FILE_APPEND`
 * :setting:`LOG_ENABLED`
 * :setting:`LOG_ENCODING`
 * :setting:`LOG_LEVEL`
@@ -155,7 +175,9 @@ The first couple of settings define a destination for log messages. If
 :setting:`LOG_FILE` is set, messages sent through the root logger will be
 redirected to a file named :setting:`LOG_FILE` with encoding
 :setting:`LOG_ENCODING`. If unset and :setting:`LOG_ENABLED` is ``True``, log
-messages will be displayed on the standard error. Lastly, if
+messages will be displayed on the standard error. If :setting:`LOG_FILE` is set
+and :setting:`LOG_FILE_APPEND` is ``False``, the file will be overwritten
+(discarding the output from previous runs, if any). Lastly, if
 :setting:`LOG_ENABLED` is ``False``, there won't be any visible log output.
 
 :setting:`LOG_LEVEL` determines the minimum level of severity to display, those
@@ -215,7 +237,7 @@ For example, let's say you're scraping a website which returns many
 HTTP 404 and 500 responses, and you want to hide all messages like this::
 
     2016-12-16 22:00:06 [scrapy.spidermiddlewares.httperror] INFO: Ignoring
-    response <500 http://quotes.toscrape.com/page/1-34/>: HTTP status code
+    response <500 https://quotes.toscrape.com/page/1-34/>: HTTP status code
     is not handled or not allowed
 
 The first thing to note is a logger name - it is in brackets:
@@ -226,7 +248,9 @@ the crawl.
 Next, we can see that the message has INFO level. To hide it
 we should set logging level for ``scrapy.spidermiddlewares.httperror``
 higher than INFO; next level after INFO is WARNING. It could be done
-e.g. in the spider's ``__init__`` method::
+e.g. in the spider's ``__init__`` method:
+
+.. code-block:: python
 
     import logging
     import scrapy
@@ -235,13 +259,64 @@ e.g. in the spider's ``__init__`` method::
     class MySpider(scrapy.Spider):
         # ...
         def __init__(self, *args, **kwargs):
-            logger = logging.getLogger('scrapy.spidermiddlewares.httperror')
+            logger = logging.getLogger("scrapy.spidermiddlewares.httperror")
             logger.setLevel(logging.WARNING)
             super().__init__(*args, **kwargs)
 
 If you run this spider again then INFO messages from
 ``scrapy.spidermiddlewares.httperror`` logger will be gone.
 
+You can also filter log records by :class:`~logging.LogRecord` data. For 
+example, you can filter log records by message content using a substring or
+a regular expression. Create a :class:`logging.Filter` subclass 
+and equip it with a regular expression pattern to
+filter out unwanted messages:
+
+.. code-block:: python
+
+    import logging
+    import re
+
+
+    class ContentFilter(logging.Filter):
+        def filter(self, record):
+            match = re.search(r"\d{3} [Ee]rror, retrying", record.message)
+            if match:
+                return False
+
+A project-level filter may be attached to the root 
+handler created by Scrapy, this is a wieldy way to 
+filter all loggers in different parts of the project
+(middlewares, spider, etc.):
+
+.. code-block:: python
+
+ import logging
+ import scrapy
+
+
+ class MySpider(scrapy.Spider):
+     # ...
+     def __init__(self, *args, **kwargs):
+         for handler in logging.root.handlers:
+             handler.addFilter(ContentFilter())
+
+Alternatively, you may choose a specific logger 
+and hide it without affecting other loggers:
+
+.. code-block:: python
+
+    import logging
+    import scrapy
+
+
+    class MySpider(scrapy.Spider):
+        # ...
+        def __init__(self, *args, **kwargs):
+            logger = logging.getLogger("my_logger")
+            logger.addFilter(ContentFilter())
+
+
 scrapy.utils.log module
 =======================
 
@@ -262,14 +337,14 @@ scrapy.utils.log module
     so it is recommended to only use :func:`logging.basicConfig` together with
     :class:`~scrapy.crawler.CrawlerRunner`.
 
-    This is an example on how to redirect ``INFO`` or higher messages to a file::
+    This is an example on how to redirect ``INFO`` or higher messages to a file:
+
+    .. code-block:: python
 
         import logging
 
         logging.basicConfig(
-            filename='log.txt',
-            format='%(levelname)s: %(message)s',
-            level=logging.INFO
+            filename="log.txt", format="%(levelname)s: %(message)s", level=logging.INFO
         )
 
     Refer to :ref:`run-from-script` for more details about using Scrapy this

docs/topics/media-pipeline.rst

@@ -56,6 +56,8 @@ this:
    error will be logged and the file won't be present in the ``files`` field.
 
 
+.. _images-pipeline:
+
 Using the Images Pipeline
 =========================
 
@@ -68,14 +70,10 @@ The advantage of using the :class:`ImagesPipeline` for image files is that you
 can configure some extra functions like generating thumbnails and filtering
 the images based on their size.
 
-The Images Pipeline uses `Pillow`_ for thumbnailing and normalizing images to
-JPEG/RGB format, so you need to install this library in order to use it.
-`Python Imaging Library`_ (PIL) should also work in most cases, but it is known
-to cause troubles in some setups, so we recommend to use `Pillow`_ instead of
-PIL.
+The Images Pipeline requires Pillow_ 7.1.0 or greater. It is used for
+thumbnailing and normalizing images to JPEG/RGB format.
 
 .. _Pillow: https://github.com/python-pillow/Pillow
-.. _Python Imaging Library: http://www.pythonware.com/products/pil/
 
 
 .. _topics-media-pipeline-enabling:
@@ -89,13 +87,17 @@ Enabling your Media Pipeline
 To enable your media pipeline you must first add it to your project
 :setting:`ITEM_PIPELINES` setting.
 
-For Images Pipeline, use::
+For Images Pipeline, use:
 
-    ITEM_PIPELINES = {'scrapy.pipelines.images.ImagesPipeline': 1}
+.. code-block:: python
 
-For Files Pipeline, use::
+    ITEM_PIPELINES = {"scrapy.pipelines.images.ImagesPipeline": 1}
 
-    ITEM_PIPELINES = {'scrapy.pipelines.files.FilesPipeline': 1}
+For Files Pipeline, use:
+
+.. code-block:: python
+
+    ITEM_PIPELINES = {"scrapy.pipelines.files.FilesPipeline": 1}
 
 .. note::
     You can also use both the Files and Images Pipeline at the same time.
@@ -105,13 +107,84 @@ Then, configure the target storage setting to a valid value that will be used
 for storing the downloaded images. Otherwise the pipeline will remain disabled,
 even if you include it in the :setting:`ITEM_PIPELINES` setting.
 
-For the Files Pipeline, set the :setting:`FILES_STORE` setting::
+For the Files Pipeline, set the :setting:`FILES_STORE` setting:
 
-   FILES_STORE = '/path/to/valid/dir'
+.. code-block:: python
 
-For the Images Pipeline, set the :setting:`IMAGES_STORE` setting::
+   FILES_STORE = "/path/to/valid/dir"
 
-   IMAGES_STORE = '/path/to/valid/dir'
+For the Images Pipeline, set the :setting:`IMAGES_STORE` setting:
+
+.. code-block:: python
+
+   IMAGES_STORE = "/path/to/valid/dir"
+
+.. _topics-file-naming:
+
+File Naming
+===========
+
+Default File Naming
+-------------------
+
+By default, files are stored using an `SHA-1 hash`_ of their URLs for the file names.
+
+For example, the following image URL::
+
+    http://www.example.com/image.jpg
+
+Whose ``SHA-1 hash`` is::
+
+    3afec3b4765f8f0a07b78f98c07b83f013567a0a
+
+Will be downloaded and stored using your chosen :ref:`storage method <topics-supported-storage>` and the following file name::
+
+   3afec3b4765f8f0a07b78f98c07b83f013567a0a.jpg
+
+Custom File Naming
+-------------------
+
+You may wish to use a different calculated file name for saved files.
+For example, classifying an image by including meta in the file name.
+
+Customize file names by overriding the ``file_path`` method of your
+media pipeline.
+
+For example, an image pipeline with image URL::
+
+   http://www.example.com/product/images/large/front/0000000004166
+
+Can be processed into a file name with a condensed hash and the perspective
+``front``::
+
+  00b08510e4_front.jpg
+
+By overriding ``file_path`` like this:
+
+.. code-block:: python
+
+  import hashlib
+
+
+  def file_path(self, request, response=None, info=None, *, item=None):
+      image_url_hash = hashlib.shake_256(request.url.encode()).hexdigest(5)
+      image_perspective = request.url.split("/")[-2]
+      image_filename = f"{image_url_hash}_{image_perspective}.jpg"
+
+      return image_filename
+
+.. warning::
+  If your custom file name scheme relies on meta data that can vary between
+  scrapes it may lead to unexpected re-downloading of existing media using
+  new file names.
+
+  For example, if your custom file name scheme uses a product title and the
+  site changes an item's product title between scrapes, Scrapy will re-download
+  the same media using updated file names.
+
+For more information about the ``file_path`` method, see :ref:`topics-media-pipeline-override`.
+
+.. _topics-supported-storage:
 
 Supported Storage
 =================
@@ -119,19 +192,9 @@ Supported Storage
 File system storage
 -------------------
 
-The files are stored using a `SHA1 hash`_ of their URLs for the file names.
+File system storage will save files to the following path::
 
-For example, the following image URL::
-
-    http://www.example.com/image.jpg
-
-Whose ``SHA1 hash`` is::
-
-    3afec3b4765f8f0a07b78f98c07b83f013567a0a
-
-Will be downloaded and stored in the following file::
-
-   <IMAGES_STORE>/full/3afec3b4765f8f0a07b78f98c07b83f013567a0a.jpg
+   <IMAGES_STORE>/full/<FILE_NAME>
 
 Where:
 
@@ -141,6 +204,9 @@ Where:
 * ``full`` is a sub-directory to separate full images from thumbnails (if
   used). For more info see :ref:`topics-images-thumbnails`.
 
+* ``<FILE_NAME>`` is the file name assigned to the file.  For more info see :ref:`topics-file-naming`.
+
+
 .. _media-pipeline-ftp:
 
 FTP server storage
@@ -164,42 +230,55 @@ FTP supports two different connection modes: active or passive. Scrapy uses
 the passive connection mode by default. To use the active connection mode instead,
 set the :setting:`FEED_STORAGE_FTP_ACTIVE` setting to ``True``.
 
+.. _media-pipelines-s3:
+
 Amazon S3 storage
 -----------------
 
 .. setting:: FILES_STORE_S3_ACL
 .. setting:: IMAGES_STORE_S3_ACL
 
-:setting:`FILES_STORE` and :setting:`IMAGES_STORE` can represent an Amazon S3
-bucket. Scrapy will automatically upload the files to the bucket.
+If botocore_ >= 1.4.87 is installed, :setting:`FILES_STORE` and
+:setting:`IMAGES_STORE` can represent an Amazon S3 bucket. Scrapy will
+automatically upload the files to the bucket.
 
-For example, this is a valid :setting:`IMAGES_STORE` value::
+For example, this is a valid :setting:`IMAGES_STORE` value:
 
-    IMAGES_STORE = 's3://bucket/images'
+.. code-block:: python
+
+    IMAGES_STORE = "s3://bucket/images"
 
 You can modify the Access Control List (ACL) policy used for the stored files,
 which is defined by the :setting:`FILES_STORE_S3_ACL` and
 :setting:`IMAGES_STORE_S3_ACL` settings. By default, the ACL is set to
 ``private``. To make the files publicly available use the ``public-read``
-policy::
+policy:
 
-    IMAGES_STORE_S3_ACL = 'public-read'
+.. code-block:: python
+
+    IMAGES_STORE_S3_ACL = "public-read"
 
 For more information, see `canned ACLs`_ in the Amazon S3 Developer Guide.
 
-Because Scrapy uses ``botocore`` internally you can also use other S3-like storages. Storages like
-self-hosted `Minio`_ or `s3.scality`_. All you need to do is set endpoint option in you Scrapy settings::
+You can also use other S3-like storages. Storages like self-hosted `Minio`_ or
+`s3.scality`_. All you need to do is set endpoint option in you Scrapy
+settings:
 
-    AWS_ENDPOINT_URL = 'http://minio.example.com:9000'
+.. code-block:: python
 
-For self-hosting you also might feel the need not to use SSL and not to verify SSL connection::
+    AWS_ENDPOINT_URL = "http://minio.example.com:9000"
 
-    AWS_USE_SSL = False # or True (None by default)
-    AWS_VERIFY = False # or True (None by default)
+For self-hosting you also might feel the need not to use SSL and not to verify SSL connection:
 
+.. code-block:: python
+
+    AWS_USE_SSL = False  # or True (None by default)
+    AWS_VERIFY = False  # or True (None by default)
+
+.. _botocore: https://github.com/boto/botocore
+.. _canned ACLs: https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl
 .. _Minio: https://github.com/minio/minio
 .. _s3.scality: https://s3.scality.com/
-.. _canned ACLs: https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl
 
 
 .. _media-pipeline-gcs:
@@ -215,10 +294,12 @@ bucket. Scrapy will automatically upload the files to the bucket. (requires `goo
 
 .. _google-cloud-storage: https://cloud.google.com/storage/docs/reference/libraries#client-libraries-install-python
 
-For example, these are valid :setting:`IMAGES_STORE` and :setting:`GCS_PROJECT_ID` settings::
+For example, these are valid :setting:`IMAGES_STORE` and :setting:`GCS_PROJECT_ID` settings:
 
-    IMAGES_STORE = 'gs://bucket/images/'
-    GCS_PROJECT_ID = 'project_id'
+.. code-block:: python
+
+    IMAGES_STORE = "gs://bucket/images/"
+    GCS_PROJECT_ID = "project_id"
 
 For information about authentication, see this `documentation`_.
 
@@ -229,9 +310,11 @@ which is defined by the :setting:`FILES_STORE_GCS_ACL` and
 :setting:`IMAGES_STORE_GCS_ACL` settings. By default, the ACL is set to
 ``''`` (empty string) which means that Cloud Storage applies the bucket's default object ACL to the object.
 To make the files publicly available use the ``publicRead``
-policy::
+policy:
 
-    IMAGES_STORE_GCS_ACL = 'publicRead'
+.. code-block:: python
+
+    IMAGES_STORE_GCS_ACL = "publicRead"
 
 For more information, see `Predefined ACLs`_ in the Google Cloud Platform Developer Guide.
 
@@ -256,10 +339,13 @@ respectively), the pipeline will put the results under the respective field
 When using :ref:`item types <item-types>` for which fields are defined beforehand,
 you must define both the URLs field and the results field. For example, when
 using the images pipeline, items must define both the ``image_urls`` and the
-``images`` field. For instance, using the :class:`~scrapy.item.Item` class::
+``images`` field. For instance, using the :class:`~scrapy.Item` class:
+
+.. code-block:: python
 
     import scrapy
 
+
     class MyItem(scrapy.Item):
         # ... other item fields ...
         image_urls = scrapy.Field()
@@ -269,16 +355,20 @@ If you want to use another field name for the URLs key or for the results key,
 it is also possible to override it.
 
 For the Files Pipeline, set :setting:`FILES_URLS_FIELD` and/or
-:setting:`FILES_RESULT_FIELD` settings::
+:setting:`FILES_RESULT_FIELD` settings:
 
-    FILES_URLS_FIELD = 'field_name_for_your_files_urls'
-    FILES_RESULT_FIELD = 'field_name_for_your_processed_files'
+.. code-block:: python
+
+    FILES_URLS_FIELD = "field_name_for_your_files_urls"
+    FILES_RESULT_FIELD = "field_name_for_your_processed_files"
 
 For the Images Pipeline, set :setting:`IMAGES_URLS_FIELD` and/or
-:setting:`IMAGES_RESULT_FIELD` settings::
+:setting:`IMAGES_RESULT_FIELD` settings:
 
-    IMAGES_URLS_FIELD = 'field_name_for_your_images_urls'
-    IMAGES_RESULT_FIELD = 'field_name_for_your_processed_images'
+.. code-block:: python
+
+    IMAGES_URLS_FIELD = "field_name_for_your_images_urls"
+    IMAGES_RESULT_FIELD = "field_name_for_your_processed_images"
 
 If you need something more complex and want to override the custom pipeline
 behaviour, see :ref:`topics-media-pipeline-override`.
@@ -293,6 +383,8 @@ setting MYPIPELINE_IMAGES_URLS_FIELD and your custom settings will be used.
 Additional features
 ===================
 
+.. _file-expiration:
+
 File expiration
 ---------------
 
@@ -302,7 +394,9 @@ File expiration
 The Image Pipeline avoids downloading files that were downloaded recently. To
 adjust this retention delay use the :setting:`FILES_EXPIRES` setting (or
 :setting:`IMAGES_EXPIRES`, in case of Images Pipeline), which
-specifies the delay in number of days::
+specifies the delay in number of days:
+
+.. code-block:: python
 
     # 120 days of delay for files expiration
     FILES_EXPIRES = 120
@@ -320,6 +414,9 @@ class name. E.g. given pipeline class called MyPipeline you can set setting key:
 
 and pipeline class MyPipeline will have expiration time set to 180.
 
+The last modified time from the file is used to determine the age of the file in days, 
+which is then compared to the set expiration time to determine if the file is expired.
+
 .. _topics-images-thumbnails:
 
 Thumbnail generation for images
@@ -333,11 +430,13 @@ images.
 In order to use this feature, you must set :setting:`IMAGES_THUMBS` to a dictionary
 where the keys are the thumbnail names and the values are their dimensions.
 
-For example::
+For example:
+
+.. code-block:: python
 
    IMAGES_THUMBS = {
-       'small': (50, 50),
-       'big': (270, 270),
+       "small": (50, 50),
+       "big": (270, 270),
    }
 
 When you use this feature, the Images Pipeline will create thumbnails of the
@@ -350,9 +449,9 @@ Where:
 * ``<size_name>`` is the one specified in the :setting:`IMAGES_THUMBS`
   dictionary keys (``small``, ``big``, etc)
 
-* ``<image_id>`` is the `SHA1 hash`_ of the image url
+* ``<image_id>`` is the `SHA-1 hash`_ of the image url
 
-.. _SHA1 hash: https://en.wikipedia.org/wiki/SHA_hash_functions
+.. _SHA-1 hash: https://en.wikipedia.org/wiki/SHA_hash_functions
 
 Example of image files stored using ``small`` and ``big`` thumbnail names::
 
@@ -421,24 +520,26 @@ See here the methods that you can override in your custom Files Pipeline:
       In addition to ``response``, this method receives the original
       :class:`request <scrapy.Request>`,
       :class:`info <scrapy.pipelines.media.MediaPipeline.SpiderInfo>` and 
-      :class:`item <scrapy.item.Item>`
+      :class:`item <scrapy.Item>`
 
       You can override this method to customize the download path of each file.
 
       For example, if file URLs end like regular paths (e.g.
       ``https://example.com/a/b/c/foo.png``), you can use the following
       approach to download all files into the ``files`` folder with their
-      original filenames (e.g. ``files/foo.png``)::
+      original filenames (e.g. ``files/foo.png``):
 
-        import os
+      .. code-block:: python
+
+        from pathlib import PurePosixPath
         from urllib.parse import urlparse
 
         from scrapy.pipelines.files import FilesPipeline
 
-        class MyFilesPipeline(FilesPipeline):
 
+        class MyFilesPipeline(FilesPipeline):
             def file_path(self, request, response=None, info=None, *, item=None):
-                return 'files/' + os.path.basename(urlparse(request.url).path)
+                return "files/" + PurePosixPath(urlparse(request.url).path).name
 
       Similarly, you can use the ``item`` to determine the file path based on some item 
       property.
@@ -446,18 +547,24 @@ See here the methods that you can override in your custom Files Pipeline:
       By default the :meth:`file_path` method returns
       ``full/<request URL hash>.<extension>``.
 
+      .. versionadded:: 2.4
+         The *item* parameter.
+
    .. method:: FilesPipeline.get_media_requests(item, info)
 
       As seen on the workflow, the pipeline will get the URLs of the images to
       download from the item. In order to do this, you can override the
       :meth:`~get_media_requests` method and return a Request for each
-      file URL::
+      file URL:
+
+      .. code-block:: python
 
          from itemadapter import ItemAdapter
 
+
          def get_media_requests(self, item, info):
              adapter = ItemAdapter(item)
-             for file_url in adapter['file_urls']:
+             for file_url in adapter["file_urls"]:
                  yield scrapy.Request(file_url)
 
       Those requests will be processed by the pipeline and, when they have finished
@@ -497,15 +604,26 @@ See here the methods that you can override in your custom Files Pipeline:
       guaranteed to retain the same order of the requests returned from the
       :meth:`~get_media_requests` method.
 
-      Here's a typical value of the ``results`` argument::
+      Here's a typical value of the ``results`` argument:
 
-          [(True,
-            {'checksum': '2b00042f7481c7b056c4b410d28f33cf',
-             'path': 'full/0a79c461a4062ac383dc4fade7bc09f1384a3910.jpg',
-             'url': 'http://www.example.com/files/product1.pdf',
-             'status': 'downloaded'}),
-           (False,
-            Failure(...))]
+      .. invisible-code-block: python
+
+          from twisted.python.failure import Failure
+
+      .. code-block:: python
+
+          [
+              (
+                  True,
+                  {
+                      "checksum": "2b00042f7481c7b056c4b410d28f33cf",
+                      "path": "full/0a79c461a4062ac383dc4fade7bc09f1384a3910.jpg",
+                      "url": "http://www.example.com/files/product1.pdf",
+                      "status": "downloaded",
+                  },
+              ),
+              (False, Failure(...)),
+          ]
 
       By default the :meth:`get_media_requests` method returns ``None`` which
       means there are no files to download for the item.
@@ -522,17 +640,20 @@ See here the methods that you can override in your custom Files Pipeline:
 
       Here is an example of the :meth:`~item_completed` method where we
       store the downloaded file paths (passed in results) in the ``file_paths``
-      item field, and we drop the item if it doesn't contain any files::
+      item field, and we drop the item if it doesn't contain any files:
+
+      .. code-block:: python
 
           from itemadapter import ItemAdapter
           from scrapy.exceptions import DropItem
 
+
           def item_completed(self, results, item, info):
-              file_paths = [x['path'] for ok, x in results if ok]
+              file_paths = [x["path"] for ok, x in results if ok]
               if not file_paths:
                   raise DropItem("Item contains no files")
               adapter = ItemAdapter(item)
-              adapter['file_paths'] = file_paths
+              adapter["file_paths"] = file_paths
               return item
 
       By default, the :meth:`item_completed` method returns the item.
@@ -557,24 +678,26 @@ See here the methods that you can override in your custom Images Pipeline:
       In addition to ``response``, this method receives the original
       :class:`request <scrapy.Request>`,
       :class:`info <scrapy.pipelines.media.MediaPipeline.SpiderInfo>` and 
-      :class:`item <scrapy.item.Item>`
+      :class:`item <scrapy.Item>`
 
       You can override this method to customize the download path of each file.
 
       For example, if file URLs end like regular paths (e.g.
       ``https://example.com/a/b/c/foo.png``), you can use the following
       approach to download all files into the ``files`` folder with their
-      original filenames (e.g. ``files/foo.png``)::
+      original filenames (e.g. ``files/foo.png``):
 
-        import os
+      .. code-block:: python
+
+        from pathlib import PurePosixPath
         from urllib.parse import urlparse
 
         from scrapy.pipelines.images import ImagesPipeline
 
-        class MyImagesPipeline(ImagesPipeline):
 
+        class MyImagesPipeline(ImagesPipeline):
             def file_path(self, request, response=None, info=None, *, item=None):
-                return 'files/' + os.path.basename(urlparse(request.url).path)
+                return "files/" + PurePosixPath(urlparse(request.url).path).name
 
       Similarly, you can use the ``item`` to determine the file path based on some item 
       property.
@@ -582,6 +705,29 @@ See here the methods that you can override in your custom Images Pipeline:
       By default the :meth:`file_path` method returns
       ``full/<request URL hash>.<extension>``.
 
+      .. versionadded:: 2.4
+         The *item* parameter.
+
+   .. method:: ImagesPipeline.thumb_path(self, request, thumb_id, response=None, info=None, *, item=None)
+
+      This method is called for every item of  :setting:`IMAGES_THUMBS` per downloaded item. It returns the
+      thumbnail download path of the image originating from the specified
+      :class:`response <scrapy.http.Response>`.
+
+      In addition to ``response``, this method receives the original
+      :class:`request <scrapy.Request>`,
+      ``thumb_id``,
+      :class:`info <scrapy.pipelines.media.MediaPipeline.SpiderInfo>` and
+      :class:`item <scrapy.Item>`.
+
+      You can override this method to customize the thumbnail download path of each image.
+      You can use the ``item`` to determine the file path based on some item
+      property.
+
+      By default the :meth:`thumb_path` method returns
+      ``thumbs/<size name>/<request URL hash>.<extension>``.
+
+
    .. method:: ImagesPipeline.get_media_requests(item, info)
 
       Works the same way as :meth:`FilesPipeline.get_media_requests` method,
@@ -607,33 +753,35 @@ Custom Images pipeline example
 ==============================
 
 Here is a full example of the Images Pipeline whose methods are exemplified
-above::
+above:
+
+.. code-block:: python
 
     import scrapy
     from itemadapter import ItemAdapter
     from scrapy.exceptions import DropItem
     from scrapy.pipelines.images import ImagesPipeline
 
-    class MyImagesPipeline(ImagesPipeline):
 
+    class MyImagesPipeline(ImagesPipeline):
         def get_media_requests(self, item, info):
-            for image_url in item['image_urls']:
+            for image_url in item["image_urls"]:
                 yield scrapy.Request(image_url)
 
         def item_completed(self, results, item, info):
-            image_paths = [x['path'] for ok, x in results if ok]
+            image_paths = [x["path"] for ok, x in results if ok]
             if not image_paths:
                 raise DropItem("Item contains no images")
             adapter = ItemAdapter(item)
-            adapter['image_paths'] = image_paths
+            adapter["image_paths"] = image_paths
             return item
 
 
 To enable your custom media pipeline component you must add its class import path to the
-:setting:`ITEM_PIPELINES` setting, like in the following example::
+:setting:`ITEM_PIPELINES` setting, like in the following example:
 
-   ITEM_PIPELINES = {
-       'myproject.pipelines.MyImagesPipeline': 300
-   }
+.. code-block:: python
+
+   ITEM_PIPELINES = {"myproject.pipelines.MyImagesPipeline": 300}
 
 .. _MD5 hash: https://en.wikipedia.org/wiki/MD5

docs/topics/practices.rst

@@ -7,6 +7,8 @@ Common Practices
 This section documents common practices when using Scrapy. These are things
 that cover many topics and don't often fall into any other specific section.
 
+.. skip: start
+
 .. _run-from-script:
 
 Run Scrapy from a script
@@ -25,23 +27,27 @@ the one used by all Scrapy commands.
 
 Here's an example showing how to run a single spider with it.
 
-::
+.. code-block:: python
 
     import scrapy
     from scrapy.crawler import CrawlerProcess
 
+
     class MySpider(scrapy.Spider):
         # Your spider definition
         ...
 
-    process = CrawlerProcess(settings={
-        "FEEDS": {
-            "items.json": {"format": "json"},
-        },
-    })
+
+    process = CrawlerProcess(
+        settings={
+            "FEEDS": {
+                "items.json": {"format": "json"},
+            },
+        }
+    )
 
     process.crawl(MySpider)
-    process.start() # the script will block here until the crawling is finished
+    process.start()  # the script will block here until the crawling is finished
 
 Define settings within dictionary in CrawlerProcess. Make sure to check :class:`~scrapy.crawler.CrawlerProcess`
 documentation to get acquainted with its usage details.
@@ -55,7 +61,7 @@ instance with your project settings.
 What follows is a working example of how to do that, using the `testspiders`_
 project as example.
 
-::
+.. code-block:: python
 
     from scrapy.crawler import CrawlerProcess
     from scrapy.utils.project import get_project_settings
@@ -63,8 +69,8 @@ project as example.
     process = CrawlerProcess(get_project_settings())
 
     # 'followall' is the name of one of the spiders of the project.
-    process.crawl('followall', domain='scrapinghub.com')
-    process.start() # the script will block here until the crawling is finished
+    process.crawl("followall", domain="scrapy.org")
+    process.start()  # the script will block here until the crawling is finished
 
 There's another Scrapy utility that provides more control over the crawling
 process: :class:`scrapy.crawler.CrawlerRunner`. This class is a thin wrapper
@@ -84,23 +90,25 @@ returned by the :meth:`CrawlerRunner.crawl
 Here's an example of its usage, along with a callback to manually stop the
 reactor after ``MySpider`` has finished running.
 
-::
+.. code-block:: python
 
     from twisted.internet import reactor
     import scrapy
     from scrapy.crawler import CrawlerRunner
     from scrapy.utils.log import configure_logging
 
+
     class MySpider(scrapy.Spider):
         # Your spider definition
         ...
 
-    configure_logging({'LOG_FORMAT': '%(levelname)s: %(message)s'})
+
+    configure_logging({"LOG_FORMAT": "%(levelname)s: %(message)s"})
     runner = CrawlerRunner()
 
     d = runner.crawl(MySpider)
     d.addBoth(lambda _: reactor.stop())
-    reactor.run() # the script will block here until the crawling is finished
+    reactor.run()  # the script will block here until the crawling is finished
 
 .. seealso:: :doc:`twisted:core/howto/reactor-basics`
 
@@ -115,68 +123,84 @@ the :ref:`internal API <topics-api>`.
 
 Here is an example that runs multiple spiders simultaneously:
 
-::
+.. code-block:: python
 
     import scrapy
     from scrapy.crawler import CrawlerProcess
+    from scrapy.utils.project import get_project_settings
+
 
     class MySpider1(scrapy.Spider):
         # Your first spider definition
         ...
 
+
     class MySpider2(scrapy.Spider):
         # Your second spider definition
         ...
 
-    process = CrawlerProcess()
+
+    settings = get_project_settings()
+    process = CrawlerProcess(settings)
     process.crawl(MySpider1)
     process.crawl(MySpider2)
-    process.start() # the script will block here until all crawling jobs are finished
+    process.start()  # the script will block here until all crawling jobs are finished
 
 Same example using :class:`~scrapy.crawler.CrawlerRunner`:
 
-::
+.. code-block:: python
 
     import scrapy
     from twisted.internet import reactor
     from scrapy.crawler import CrawlerRunner
     from scrapy.utils.log import configure_logging
+    from scrapy.utils.project import get_project_settings
+
 
     class MySpider1(scrapy.Spider):
         # Your first spider definition
         ...
 
+
     class MySpider2(scrapy.Spider):
         # Your second spider definition
         ...
 
+
     configure_logging()
-    runner = CrawlerRunner()
+    settings = get_project_settings()
+    runner = CrawlerRunner(settings)
     runner.crawl(MySpider1)
     runner.crawl(MySpider2)
     d = runner.join()
     d.addBoth(lambda _: reactor.stop())
 
-    reactor.run() # the script will block here until all crawling jobs are finished
+    reactor.run()  # the script will block here until all crawling jobs are finished
 
 Same example but running the spiders sequentially by chaining the deferreds:
 
-::
+.. code-block:: python
 
     from twisted.internet import reactor, defer
     from scrapy.crawler import CrawlerRunner
     from scrapy.utils.log import configure_logging
+    from scrapy.utils.project import get_project_settings
+
 
     class MySpider1(scrapy.Spider):
         # Your first spider definition
         ...
 
+
     class MySpider2(scrapy.Spider):
         # Your second spider definition
         ...
 
-    configure_logging()
-    runner = CrawlerRunner()
+
+    settings = get_project_settings()
+    configure_logging(settings)
+    runner = CrawlerRunner(settings)
+
 
     @defer.inlineCallbacks
     def crawl():
@@ -184,11 +208,33 @@ Same example but running the spiders sequentially by chaining the deferreds:
         yield runner.crawl(MySpider2)
         reactor.stop()
 
+
     crawl()
-    reactor.run() # the script will block here until the last crawl call is finished
+    reactor.run()  # the script will block here until the last crawl call is finished
+
+Different spiders can set different values for the same setting, but when they
+run in the same process it may be impossible, by design or because of some
+limitations, to use these different values. What happens in practice is
+different for different settings:
+
+* :setting:`SPIDER_LOADER_CLASS` and the ones used by its value
+  (:setting:`SPIDER_MODULES`, :setting:`SPIDER_LOADER_WARN_ONLY` for the
+  default one) cannot be read from the per-spider settings. These are applied
+  when the :class:`~scrapy.crawler.CrawlerRunner` or
+  :class:`~scrapy.crawler.CrawlerProcess` object is created.
+* For :setting:`TWISTED_REACTOR` and :setting:`ASYNCIO_EVENT_LOOP` the first
+  available value is used, and if a spider requests a different reactor an
+  exception will be raised. These are applied when the reactor is installed.
+* For :setting:`REACTOR_THREADPOOL_MAXSIZE`, :setting:`DNS_RESOLVER` and the
+  ones used by the resolver (:setting:`DNSCACHE_ENABLED`,
+  :setting:`DNSCACHE_SIZE`, :setting:`DNS_TIMEOUT` for ones included in Scrapy)
+  the first available value is used. These are applied when the reactor is
+  started.
 
 .. seealso:: :ref:`run-from-script`.
 
+.. skip: end
+
 .. _distributed-crawls:
 
 Distributed crawls
@@ -237,14 +283,13 @@ Here are some tips to keep in mind when dealing with these kinds of sites:
 * disable cookies (see :setting:`COOKIES_ENABLED`) as some sites may use
   cookies to spot bot behaviour
 * use download delays (2 or higher). See :setting:`DOWNLOAD_DELAY` setting.
-* if possible, use `Google cache`_ to fetch pages, instead of hitting the sites
+* if possible, use `Common Crawl`_ to fetch pages, instead of hitting the sites
   directly
 * use a pool of rotating IPs. For example, the free `Tor project`_ or paid
   services like `ProxyMesh`_. An open source alternative is `scrapoxy`_, a
   super proxy that you can attach your own proxies to.
-* use a highly distributed downloader that circumvents bans internally, so you
-  can just focus on parsing clean pages. One example of such downloaders is
-  `Crawlera`_
+* use a ban avoidance service, such as `Zyte API`_, which provides a `Scrapy
+  plugin <https://github.com/scrapy-plugins/scrapy-zyte-api>`__
 
 If you are still unable to prevent your bot getting banned, consider contacting
 `commercial support`_.
@@ -252,7 +297,7 @@ If you are still unable to prevent your bot getting banned, consider contacting
 .. _Tor project: https://www.torproject.org/
 .. _commercial support: https://scrapy.org/support/
 .. _ProxyMesh: https://proxymesh.com/
-.. _Google cache: http://www.googleguide.com/cached_pages.html
+.. _Common Crawl: https://commoncrawl.org/
 .. _testspiders: https://github.com/scrapinghub/testspiders
-.. _Crawlera: https://scrapinghub.com/crawlera
 .. _scrapoxy: https://scrapoxy.io/
+.. _Zyte API: https://docs.zyte.com/zyte-api/get-started.html

docs/topics/request-response.rst

@@ -26,21 +26,26 @@ Request objects
 
 .. autoclass:: Request
 
-    A :class:`Request` object represents an HTTP request, which is usually
-    generated in the Spider and executed by the Downloader, and thus generating
-    a :class:`Response`.
-
     :param url: the URL of this request
 
         If the URL is invalid, a :exc:`ValueError` exception is raised.
     :type url: str
 
     :param callback: the function that will be called with the response of this
-       request (once it's downloaded) as its first parameter. For more information
-       see :ref:`topics-request-response-ref-request-callback-arguments` below.
-       If a Request doesn't specify a callback, the spider's
-       :meth:`~scrapy.spiders.Spider.parse` method will be used.
-       Note that if exceptions are raised during processing, errback is called instead.
+       request (once it's downloaded) as its first parameter.
+
+       In addition to a function, the following values are supported:
+
+       -   ``None`` (default), which indicates that the spider's
+           :meth:`~scrapy.Spider.parse` method must be used.
+
+       -   :func:`~scrapy.http.request.NO_CALLBACK`
+
+       For more information, see
+       :ref:`topics-request-response-ref-request-callback-arguments`.
+
+       .. note:: If exceptions are raised during processing, ``errback`` is
+                 called instead.
 
     :type callback: collections.abc.Callable
 
@@ -61,22 +66,44 @@ Request objects
     :param headers: the headers of this request. The dict values can be strings
        (for single valued headers) or lists (for multi-valued headers). If
        ``None`` is passed as value, the HTTP header will not be sent at all.
+
+        .. caution:: Cookies set via the ``Cookie`` header are not considered by the
+            :ref:`cookies-mw`. If you need to set cookies for a request, use the
+            :class:`Request.cookies <scrapy.Request>` parameter. This is a known
+            current limitation that is being worked on.
+
     :type headers: dict
 
     :param cookies: the request cookies. These can be sent in two forms.
 
-        1. Using a dict::
+        .. invisible-code-block: python
 
-            request_with_cookies = Request(url="http://www.example.com",
-                                           cookies={'currency': 'USD', 'country': 'UY'})
+            from scrapy.http import Request
 
-        2. Using a list of dicts::
+        1. Using a dict:
 
-            request_with_cookies = Request(url="http://www.example.com",
-                                           cookies=[{'name': 'currency',
-                                                    'value': 'USD',
-                                                    'domain': 'example.com',
-                                                    'path': '/currency'}])
+        .. code-block:: python
+
+            request_with_cookies = Request(
+                url="http://www.example.com",
+                cookies={"currency": "USD", "country": "UY"},
+            )
+
+        2. Using a list of dicts:
+
+        .. code-block:: python
+
+            request_with_cookies = Request(
+                url="http://www.example.com",
+                cookies=[
+                    {
+                        "name": "currency",
+                        "value": "USD",
+                        "domain": "example.com",
+                        "path": "/currency",
+                    },
+                ],
+            )
 
         The latter form allows for customizing the ``domain`` and ``path``
         attributes of the cookie. This is only useful if the cookies are saved
@@ -88,20 +115,21 @@ Request objects
         cookies for that domain and will be sent again in future requests.
         That's the typical behaviour of any regular web browser.
 
-        To create a request that does not send stored cookies and does not
-        store received cookies, set the ``dont_merge_cookies`` key to ``True``
-        in :attr:`request.meta <scrapy.http.Request.meta>`.
-
-        Example of a request that sends manually-defined cookies and ignores
-        cookie storage::
-
-            Request(
-                url="http://www.example.com",
-                cookies={'currency': 'USD', 'country': 'UY'},
-                meta={'dont_merge_cookies': True},
-            )
+        Note that setting the :reqmeta:`dont_merge_cookies` key to ``True`` in
+        :attr:`request.meta <scrapy.Request.meta>` causes custom cookies to be
+        ignored.
 
         For more info see :ref:`cookies-mw`.
+
+        .. caution:: Cookies set via the ``Cookie`` header are not considered by the
+            :ref:`cookies-mw`. If you need to set cookies for a request, use the
+            :class:`Request.cookies <scrapy.Request>` parameter. This is a known
+            current limitation that is being worked on.
+
+        .. versionadded:: 2.6.0
+           Cookie values that are :class:`bool`, :class:`float` or :class:`int`
+           are casted to :class:`str`.
+
     :type cookies: dict or list
 
     :param encoding: the encoding of this request (defaults to ``'utf-8'``).
@@ -165,18 +193,47 @@ Request objects
         :meth:`replace`.
 
     .. attribute:: Request.meta
+       :value: {}
 
-        A dict that contains arbitrary metadata for this request. This dict is
-        empty for new Requests, and is usually  populated by different Scrapy
-        components (extensions, middlewares, etc). So the data contained in this
-        dict depends on the extensions you have enabled.
+        A dictionary of arbitrary metadata for the request.
 
-        See :ref:`topics-request-meta` for a list of special meta keys
-        recognized by Scrapy.
+        You may extend request metadata as you see fit.
 
-        This dict is :doc:`shallow copied <library/copy>` when the request is
-        cloned using the ``copy()`` or ``replace()`` methods, and can also be
-        accessed, in your spider, from the ``response.meta`` attribute.
+        Request metadata can also be accessed through the
+        :attr:`~scrapy.http.Response.meta` attribute of a response.
+
+        To pass data from one spider callback to another, consider using
+        :attr:`cb_kwargs` instead. However, request metadata may be the right
+        choice in certain scenarios, such as to maintain some debugging data
+        across all follow-up requests (e.g. the source URL).
+
+        A common use of request metadata is to define request-specific
+        parameters for Scrapy components (extensions, middlewares, etc.). For
+        example, if you set ``dont_retry`` to ``True``,
+        :class:`~scrapy.downloadermiddlewares.retry.RetryMiddleware` will never
+        retry that request, even if it fails. See :ref:`topics-request-meta`.
+
+        You may also use request metadata in your custom Scrapy components, for
+        example, to keep request state information relevant to your component.
+        For example,
+        :class:`~scrapy.downloadermiddlewares.retry.RetryMiddleware` uses the
+        ``retry_times`` metadata key to keep track of how many times a request
+        has been retried so far.
+
+        Copying all the metadata of a previous request into a new, follow-up
+        request in a spider callback is a bad practice, because request
+        metadata may include metadata set by Scrapy components that is not
+        meant to be copied into other requests. For example, copying the
+        ``retry_times`` metadata key into follow-up requests can lower the
+        amount of retries allowed for those follow-up requests.
+
+        You should only copy all request metadata from one request to another
+        if the new request is meant to replace the old request, as is often the
+        case when returning a request from a :ref:`downloader middleware
+        <topics-downloader-middleware>` method.
+
+        Also mind that the :meth:`copy` and :meth:`replace` request methods
+        :doc:`shallow-copy <library/copy>` request metadata.
 
     .. attribute:: Request.cb_kwargs
 
@@ -193,6 +250,8 @@ Request objects
         ``failure.request.cb_kwargs`` in the request's errback. For more information,
         see :ref:`errback-cb_kwargs`.
 
+    .. autoattribute:: Request.attributes
+
     .. method:: Request.copy()
 
        Return a new Request which is a copy of this Request. See also:
@@ -208,6 +267,17 @@ Request objects
 
     .. automethod:: from_curl
 
+    .. automethod:: to_dict
+
+
+Other functions related to requests
+-----------------------------------
+
+.. autofunction:: scrapy.http.request.NO_CALLBACK
+
+.. autofunction:: scrapy.utils.request.request_from_dict
+
+
 .. _topics-request-response-ref-request-callback-arguments:
 
 Passing additional data to callback functions
@@ -217,11 +287,15 @@ The callback of a request is a function that will be called when the response
 of that request is downloaded. The callback function will be called with the
 downloaded :class:`Response` object as its first argument.
 
-Example::
+Example:
+
+.. code-block:: python
 
     def parse_page1(self, response):
-        return scrapy.Request("http://www.example.com/some_page.html",
-                              callback=self.parse_page2)
+        return scrapy.Request(
+            "http://www.example.com/some_page.html", callback=self.parse_page2
+        )
+
 
     def parse_page2(self, response):
         # this would log http://www.example.com/some_page.html
@@ -232,15 +306,18 @@ functions so you can receive the arguments later, in the second callback.
 The following example shows how to achieve this by using the
 :attr:`Request.cb_kwargs` attribute:
 
-::
+.. code-block:: python
 
     def parse(self, response):
-        request = scrapy.Request('http://www.example.com/index.html',
-                                 callback=self.parse_page2,
-                                 cb_kwargs=dict(main_url=response.url))
-        request.cb_kwargs['foo'] = 'bar'  # add more arguments for the callback
+        request = scrapy.Request(
+            "http://www.example.com/index.html",
+            callback=self.parse_page2,
+            cb_kwargs=dict(main_url=response.url),
+        )
+        request.cb_kwargs["foo"] = "bar"  # add more arguments for the callback
         yield request
 
+
     def parse_page2(self, response, main_url, foo):
         yield dict(
             main_url=main_url,
@@ -266,7 +343,9 @@ It receives a :exc:`~twisted.python.failure.Failure` as first parameter and can
 be used to track connection establishment timeouts, DNS errors etc.
 
 Here's an example spider logging all errors and catching some specific
-errors if needed::
+errors if needed:
+
+.. code-block:: python
 
     import scrapy
 
@@ -274,24 +353,28 @@ errors if needed::
     from twisted.internet.error import DNSLookupError
     from twisted.internet.error import TimeoutError, TCPTimedOutError
 
+
     class ErrbackSpider(scrapy.Spider):
         name = "errback_example"
         start_urls = [
-            "http://www.httpbin.org/",              # HTTP 200 expected
-            "http://www.httpbin.org/status/404",    # Not found error
-            "http://www.httpbin.org/status/500",    # server issue
-            "http://www.httpbin.org:12345/",        # non-responding host, timeout expected
-            "http://www.httphttpbinbin.org/",       # DNS error expected
+            "http://www.httpbin.org/",  # HTTP 200 expected
+            "http://www.httpbin.org/status/404",  # Not found error
+            "http://www.httpbin.org/status/500",  # server issue
+            "http://www.httpbin.org:12345/",  # non-responding host, timeout expected
+            "https://example.invalid/",  # DNS error expected
         ]
 
         def start_requests(self):
             for u in self.start_urls:
-                yield scrapy.Request(u, callback=self.parse_httpbin,
-                                        errback=self.errback_httpbin,
-                                        dont_filter=True)
+                yield scrapy.Request(
+                    u,
+                    callback=self.parse_httpbin,
+                    errback=self.errback_httpbin,
+                    dont_filter=True,
+                )
 
         def parse_httpbin(self, response):
-            self.logger.info('Got successful response from {}'.format(response.url))
+            self.logger.info("Got successful response from {}".format(response.url))
             # do something useful here...
 
         def errback_httpbin(self, failure):
@@ -305,16 +388,17 @@ errors if needed::
                 # these exceptions come from HttpError spider middleware
                 # you can get the non-200 response
                 response = failure.value.response
-                self.logger.error('HttpError on %s', response.url)
+                self.logger.error("HttpError on %s", response.url)
 
             elif failure.check(DNSLookupError):
                 # this is the original request
                 request = failure.request
-                self.logger.error('DNSLookupError on %s', request.url)
+                self.logger.error("DNSLookupError on %s", request.url)
 
             elif failure.check(TimeoutError, TCPTimedOutError):
                 request = failure.request
-                self.logger.error('TimeoutError on %s', request.url)
+                self.logger.error("TimeoutError on %s", request.url)
+
 
 .. _errback-cb_kwargs:
 
@@ -324,23 +408,309 @@ Accessing additional data in errback functions
 In case of a failure to process the request, you may be interested in
 accessing arguments to the callback functions so you can process further
 based on the arguments in the errback. The following example shows how to
-achieve this by using ``Failure.request.cb_kwargs``::
+achieve this by using ``Failure.request.cb_kwargs``:
+
+.. code-block:: python
 
     def parse(self, response):
-        request = scrapy.Request('http://www.example.com/index.html',
-                                 callback=self.parse_page2,
-                                 errback=self.errback_page2,
-                                 cb_kwargs=dict(main_url=response.url))
+        request = scrapy.Request(
+            "http://www.example.com/index.html",
+            callback=self.parse_page2,
+            errback=self.errback_page2,
+            cb_kwargs=dict(main_url=response.url),
+        )
         yield request
 
+
     def parse_page2(self, response, main_url):
         pass
 
+
     def errback_page2(self, failure):
         yield dict(
-            main_url=failure.request.cb_kwargs['main_url'],
+            main_url=failure.request.cb_kwargs["main_url"],
         )
 
+
+.. _request-fingerprints:
+
+Request fingerprints
+--------------------
+
+There are some aspects of scraping, such as filtering out duplicate requests
+(see :setting:`DUPEFILTER_CLASS`) or caching responses (see
+:setting:`HTTPCACHE_POLICY`), where you need the ability to generate a short,
+unique identifier from a :class:`~scrapy.http.Request` object: a request
+fingerprint.
+
+You often do not need to worry about request fingerprints, the default request
+fingerprinter works for most projects.
+
+However, there is no universal way to generate a unique identifier from a
+request, because different situations require comparing requests differently.
+For example, sometimes you may need to compare URLs case-insensitively, include
+URL fragments, exclude certain URL query parameters, include some or all
+headers, etc.
+
+To change how request fingerprints are built for your requests, use the
+:setting:`REQUEST_FINGERPRINTER_CLASS` setting.
+
+.. setting:: REQUEST_FINGERPRINTER_CLASS
+
+REQUEST_FINGERPRINTER_CLASS
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 2.7
+
+Default: :class:`scrapy.utils.request.RequestFingerprinter`
+
+A :ref:`request fingerprinter class <custom-request-fingerprinter>` or its
+import path.
+
+.. autoclass:: scrapy.utils.request.RequestFingerprinter
+
+
+.. setting:: REQUEST_FINGERPRINTER_IMPLEMENTATION
+
+REQUEST_FINGERPRINTER_IMPLEMENTATION
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 2.7
+
+Default: ``'2.6'``
+
+Determines which request fingerprinting algorithm is used by the default
+request fingerprinter class (see :setting:`REQUEST_FINGERPRINTER_CLASS`).
+
+Possible values are:
+
+-   ``'2.6'`` (default)
+
+    This implementation uses the same request fingerprinting algorithm as
+    Scrapy 2.6 and earlier versions.
+
+    Even though this is the default value for backward compatibility reasons,
+    it is a deprecated value.
+
+-   ``'2.7'``
+
+    This implementation was introduced in Scrapy 2.7 to fix an issue of the
+    previous implementation.
+
+    New projects should use this value. The :command:`startproject` command
+    sets this value in the generated ``settings.py`` file.
+
+If you are using the default value (``'2.6'``) for this setting, and you are
+using Scrapy components where changing the request fingerprinting algorithm
+would cause undesired results, you need to carefully decide when to change the
+value of this setting, or switch the :setting:`REQUEST_FINGERPRINTER_CLASS`
+setting to a custom request fingerprinter class that implements the 2.6 request
+fingerprinting algorithm and does not log this warning (
+:ref:`2.6-request-fingerprinter` includes an example implementation of such a
+class).
+
+Scenarios where changing the request fingerprinting algorithm may cause
+undesired results include, for example, using the HTTP cache middleware (see
+:class:`~scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware`).
+Changing the request fingerprinting algorithm would invalidate the current
+cache, requiring you to redownload all requests again.
+
+Otherwise, set :setting:`REQUEST_FINGERPRINTER_IMPLEMENTATION` to ``'2.7'`` in
+your settings to switch already to the request fingerprinting implementation
+that will be the only request fingerprinting implementation available in a
+future version of Scrapy, and remove the deprecation warning triggered by using
+the default value (``'2.6'``).
+
+
+.. _2.6-request-fingerprinter:
+.. _custom-request-fingerprinter:
+
+Writing your own request fingerprinter
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A request fingerprinter is a class that must implement the following method:
+
+.. currentmodule:: None
+
+.. method:: fingerprint(self, request)
+
+   Return a :class:`bytes` object that uniquely identifies *request*.
+
+   See also :ref:`request-fingerprint-restrictions`.
+
+   :param request: request to fingerprint
+   :type request: scrapy.http.Request
+
+Additionally, it may also implement the following methods:
+
+.. classmethod:: from_crawler(cls, crawler)
+   :noindex:
+
+   If present, this class method is called to create a request fingerprinter
+   instance from a :class:`~scrapy.crawler.Crawler` object. It must return a
+   new instance of the request fingerprinter.
+
+   *crawler* provides access to all Scrapy core components like settings and
+   signals; it is a way for the request fingerprinter to access them and hook
+   its functionality into Scrapy.
+
+   :param crawler: crawler that uses this request fingerprinter
+   :type crawler: :class:`~scrapy.crawler.Crawler` object
+
+.. classmethod:: from_settings(cls, settings)
+
+   If present, and ``from_crawler`` is not defined, this class method is called
+   to create a request fingerprinter instance from a
+   :class:`~scrapy.settings.Settings` object. It must return a new instance of
+   the request fingerprinter.
+
+.. currentmodule:: scrapy.http
+
+The :meth:`fingerprint` method of the default request fingerprinter,
+:class:`scrapy.utils.request.RequestFingerprinter`, uses
+:func:`scrapy.utils.request.fingerprint` with its default parameters. For some
+common use cases you can use :func:`scrapy.utils.request.fingerprint` as well
+in your :meth:`fingerprint` method implementation:
+
+.. autofunction:: scrapy.utils.request.fingerprint
+
+For example, to take the value of a request header named ``X-ID`` into
+account:
+
+.. code-block:: python
+
+    # my_project/settings.py
+    REQUEST_FINGERPRINTER_CLASS = "my_project.utils.RequestFingerprinter"
+
+    # my_project/utils.py
+    from scrapy.utils.request import fingerprint
+
+
+    class RequestFingerprinter:
+        def fingerprint(self, request):
+            return fingerprint(request, include_headers=["X-ID"])
+
+You can also write your own fingerprinting logic from scratch.
+
+However, if you do not use :func:`scrapy.utils.request.fingerprint`, make sure
+you use :class:`~weakref.WeakKeyDictionary` to cache request fingerprints:
+
+-   Caching saves CPU by ensuring that fingerprints are calculated only once
+    per request, and not once per Scrapy component that needs the fingerprint
+    of a request.
+
+-   Using :class:`~weakref.WeakKeyDictionary` saves memory by ensuring that
+    request objects do not stay in memory forever just because you have
+    references to them in your cache dictionary.
+
+For example, to take into account only the URL of a request, without any prior
+URL canonicalization or taking the request method or body into account:
+
+.. code-block:: python
+
+    from hashlib import sha1
+    from weakref import WeakKeyDictionary
+
+    from scrapy.utils.python import to_bytes
+
+
+    class RequestFingerprinter:
+        cache = WeakKeyDictionary()
+
+        def fingerprint(self, request):
+            if request not in self.cache:
+                fp = sha1()
+                fp.update(to_bytes(request.url))
+                self.cache[request] = fp.digest()
+            return self.cache[request]
+
+If you need to be able to override the request fingerprinting for arbitrary
+requests from your spider callbacks, you may implement a request fingerprinter
+that reads fingerprints from :attr:`request.meta <scrapy.http.Request.meta>`
+when available, and then falls back to
+:func:`scrapy.utils.request.fingerprint`. For example:
+
+.. code-block:: python
+
+    from scrapy.utils.request import fingerprint
+
+
+    class RequestFingerprinter:
+        def fingerprint(self, request):
+            if "fingerprint" in request.meta:
+                return request.meta["fingerprint"]
+            return fingerprint(request)
+
+If you need to reproduce the same fingerprinting algorithm as Scrapy 2.6
+without using the deprecated ``'2.6'`` value of the
+:setting:`REQUEST_FINGERPRINTER_IMPLEMENTATION` setting, use the following
+request fingerprinter:
+
+.. code-block:: python
+
+    from hashlib import sha1
+    from weakref import WeakKeyDictionary
+
+    from scrapy.utils.python import to_bytes
+    from w3lib.url import canonicalize_url
+
+
+    class RequestFingerprinter:
+        cache = WeakKeyDictionary()
+
+        def fingerprint(self, request):
+            if request not in self.cache:
+                fp = sha1()
+                fp.update(to_bytes(request.method))
+                fp.update(to_bytes(canonicalize_url(request.url)))
+                fp.update(request.body or b"")
+                self.cache[request] = fp.digest()
+            return self.cache[request]
+
+
+.. _request-fingerprint-restrictions:
+
+Request fingerprint restrictions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Scrapy components that use request fingerprints may impose additional
+restrictions on the format of the fingerprints that your :ref:`request
+fingerprinter <custom-request-fingerprinter>` generates.
+
+The following built-in Scrapy components have such restrictions:
+
+-   :class:`scrapy.extensions.httpcache.FilesystemCacheStorage` (default
+    value of :setting:`HTTPCACHE_STORAGE`)
+
+    Request fingerprints must be at least 1 byte long.
+
+    Path and filename length limits of the file system of
+    :setting:`HTTPCACHE_DIR` also apply. Inside :setting:`HTTPCACHE_DIR`,
+    the following directory structure is created:
+
+    -   :attr:`Spider.name <scrapy.spiders.Spider.name>`
+
+        -   first byte of a request fingerprint as hexadecimal
+
+            -   fingerprint as hexadecimal
+
+                -   filenames up to 16 characters long
+
+    For example, if a request fingerprint is made of 20 bytes (default),
+    :setting:`HTTPCACHE_DIR` is ``'/home/user/project/.scrapy/httpcache'``,
+    and the name of your spider is ``'my_spider'`` your file system must
+    support a file path like::
+
+        /home/user/project/.scrapy/httpcache/my_spider/01/0123456789abcdef0123456789abcdef01234567/response_headers
+
+-   :class:`scrapy.extensions.httpcache.DbmCacheStorage`
+
+    The underlying DBM implementation must support keys as long as twice
+    the number of bytes of a request fingerprint, plus 5. For example,
+    if a request fingerprint is made of 20 bytes (default),
+    45-character-long keys must be supported.
+
+
 .. _topics-request-meta:
 
 Request.meta special keys
@@ -351,26 +721,26 @@ are some special keys recognized by Scrapy and its built-in extensions.
 
 Those are:
 
-* :reqmeta:`dont_redirect`
-* :reqmeta:`dont_retry`
-* :reqmeta:`handle_httpstatus_list`
-* :reqmeta:`handle_httpstatus_all`
-* :reqmeta:`dont_merge_cookies`
+* :reqmeta:`bindaddress`
 * :reqmeta:`cookiejar`
 * :reqmeta:`dont_cache`
+* :reqmeta:`dont_merge_cookies`
+* :reqmeta:`dont_obey_robotstxt`
+* :reqmeta:`dont_redirect`
+* :reqmeta:`dont_retry`
+* :reqmeta:`download_fail_on_dataloss`
+* :reqmeta:`download_latency`
+* :reqmeta:`download_maxsize`
+* :reqmeta:`download_timeout`
+* ``ftp_password`` (See :setting:`FTP_PASSWORD` for more info)
+* ``ftp_user`` (See :setting:`FTP_USER` for more info)
+* :reqmeta:`handle_httpstatus_all`
+* :reqmeta:`handle_httpstatus_list`
+* :reqmeta:`max_retry_times`
+* :reqmeta:`proxy`
 * :reqmeta:`redirect_reasons`
 * :reqmeta:`redirect_urls`
-* :reqmeta:`bindaddress`
-* :reqmeta:`dont_obey_robotstxt`
-* :reqmeta:`download_timeout`
-* :reqmeta:`download_maxsize`
-* :reqmeta:`download_latency`
-* :reqmeta:`download_fail_on_dataloss`
-* :reqmeta:`proxy`
-* ``ftp_user`` (See :setting:`FTP_USER` for more info)
-* ``ftp_password`` (See :setting:`FTP_PASSWORD` for more info)
 * :reqmeta:`referrer_policy`
-* :reqmeta:`max_retry_times`
 
 .. reqmeta:: bindaddress
 
@@ -420,9 +790,11 @@ The meta key is used set retry times per request. When initialized, the
 Stopping the download of a Response
 ===================================
 
-Raising a :exc:`~scrapy.exceptions.StopDownload` exception from a
-:class:`~scrapy.signals.bytes_received` signal handler will stop the
-download of a given response. See the following example::
+Raising a :exc:`~scrapy.exceptions.StopDownload` exception from a handler for the
+:class:`~scrapy.signals.bytes_received` or :class:`~scrapy.signals.headers_received`
+signals will stop the download of a given response. See the following example:
+
+.. code-block:: python
 
     import scrapy
 
@@ -434,7 +806,9 @@ download of a given response. See the following example::
         @classmethod
         def from_crawler(cls, crawler):
             spider = super().from_crawler(crawler)
-            crawler.signals.connect(spider.on_bytes_received, signal=scrapy.signals.bytes_received)
+            crawler.signals.connect(
+                spider.on_bytes_received, signal=scrapy.signals.bytes_received
+            )
             return spider
 
         def parse(self, response):
@@ -476,7 +850,9 @@ fields with form data from :class:`Response` objects.
 
 .. _lxml.html forms: https://lxml.de/lxmlhtml.html#forms
 
-.. class:: FormRequest(url, [formdata, ...])
+.. class:: scrapy.http.request.form.FormRequest
+.. class:: scrapy.http.FormRequest
+.. class:: scrapy.FormRequest(url, [formdata, ...])
 
     The :class:`FormRequest` class adds a new keyword parameter to the ``__init__`` method. The
     remaining arguments are the same as for the :class:`Request` class and are
@@ -561,11 +937,18 @@ Using FormRequest to send data via HTTP POST
 
 If you want to simulate a HTML Form POST in your spider and send a couple of
 key-value fields, you can return a :class:`FormRequest` object (from your
-spider) like this::
+spider) like this:
 
-   return [FormRequest(url="http://www.example.com/post/action",
-                       formdata={'name': 'John Doe', 'age': '27'},
-                       callback=self.after_post)]
+.. skip: next
+.. code-block:: python
+
+   return [
+       FormRequest(
+           url="http://www.example.com/post/action",
+           formdata={"name": "John Doe", "age": "27"},
+           callback=self.after_post,
+       )
+   ]
 
 .. _topics-request-response-ref-request-userlogin:
 
@@ -577,25 +960,28 @@ type="hidden">`` elements, such as session related data or authentication
 tokens (for login pages). When scraping, you'll want these fields to be
 automatically pre-populated and only override a couple of them, such as the
 user name and password. You can use the :meth:`FormRequest.from_response`
-method for this job. Here's an example spider which uses it::
+method for this job. Here's an example spider which uses it:
 
+.. code-block:: python
 
     import scrapy
 
+
     def authentication_failed(response):
         # TODO: Check the contents of the response and return True if it failed
         # or False if it succeeded.
         pass
 
+
     class LoginSpider(scrapy.Spider):
-        name = 'example.com'
-        start_urls = ['http://www.example.com/users/login.php']
+        name = "example.com"
+        start_urls = ["http://www.example.com/users/login.php"]
 
         def parse(self, response):
             return scrapy.FormRequest.from_response(
                 response,
-                formdata={'username': 'john', 'password': 'secret'},
-                callback=self.after_login
+                formdata={"username": "john", "password": "secret"},
+                callback=self.after_login,
             )
 
         def after_login(self, response):
@@ -630,16 +1016,21 @@ dealing with JSON requests.
        data into JSON format.
    :type dumps_kwargs: dict
 
+   .. autoattribute:: JsonRequest.attributes
+
 JsonRequest usage example
 -------------------------
 
-Sending a JSON POST request with a JSON payload::
+Sending a JSON POST request with a JSON payload:
+
+.. skip: next
+.. code-block:: python
 
    data = {
-       'name1': 'value1',
-       'name2': 'value2',
+       "name1": "value1",
+       "name2": "value2",
    }
-   yield JsonRequest(url='http://www.example.com/post/action', data=data)
+   yield JsonRequest(url="http://www.example.com/post/action", data=data)
 
 
 Response objects
@@ -647,9 +1038,6 @@ Response objects
 
 .. autoclass:: Response
 
-    A :class:`Response` object represents an HTTP response, which is usually
-    downloaded (by the Downloader) and fed to the Spiders for processing.
-
     :param url: the URL of this response
     :type url: str
 
@@ -673,7 +1061,7 @@ Response objects
 
     :param request: the initial value of the :attr:`Response.request` attribute.
         This represents the :class:`Request` that generated this response.
-    :type request: scrapy.http.Request
+    :type request: scrapy.Request
 
     :param certificate: an object representing the server's SSL certificate.
     :type certificate: twisted.internet.ssl.Certificate
@@ -681,9 +1069,19 @@ Response objects
     :param ip_address: The IP address of the server from which the Response originated.
     :type ip_address: :class:`ipaddress.IPv4Address` or :class:`ipaddress.IPv6Address`
 
+    :param protocol: The protocol that was used to download the response.
+        For instance: "HTTP/1.0", "HTTP/1.1", "h2"
+    :type protocol: :class:`str`
+
+    .. versionadded:: 2.0.0
+       The ``certificate`` parameter.
+
     .. versionadded:: 2.1.0
        The ``ip_address`` parameter.
 
+    .. versionadded:: 2.5.0
+       The ``protocol`` parameter.
+
     .. attribute:: Response.url
 
         A string containing the URL of the response.
@@ -723,9 +1121,10 @@ Response objects
         through all :ref:`Downloader Middlewares <topics-downloader-middleware>`.
         In particular, this means that:
 
-        - HTTP redirections will cause the original request (to the URL before
-          redirection) to be assigned to the redirected response (with the final
-          URL after redirection).
+        - HTTP redirections will create a new request from the request before
+          redirection. It has the majority of the same metadata and original
+          request attributes and gets assigned to the redirected response
+          instead of the propagation of the original request.
 
         - Response.request.url doesn't always equal Response.url
 
@@ -768,6 +1167,8 @@ Response objects
 
     .. attribute:: Response.certificate
 
+        .. versionadded:: 2.0.0
+
         A :class:`twisted.internet.ssl.Certificate` object representing
         the server's SSL certificate.
 
@@ -783,6 +1184,19 @@ Response objects
         handler, i.e. for ``http(s)`` responses. For other handlers,
         :attr:`ip_address` is always ``None``.
 
+    .. attribute:: Response.protocol
+
+        .. versionadded:: 2.5.0
+
+        The protocol that was used to download the response.
+        For instance: "HTTP/1.0", "HTTP/1.1"
+
+        This attribute is currently only populated by the HTTP download
+        handlers, i.e. for ``http(s)`` responses. For other handlers,
+        :attr:`protocol` is always ``None``.
+
+    .. autoattribute:: Response.attributes
+
     .. method:: Response.copy()
 
        Returns a new Response which is a copy of this Response.
@@ -852,8 +1266,10 @@ TextResponse objects
             ``str(response.body)`` is not a correct way to convert the response
             body into a string:
 
-            >>> str(b'body')
-            "b'body'"
+            .. code-block:: pycon
+
+                >>> str(b"body")
+                "b'body'"
 
 
     .. attribute:: TextResponse.encoding
@@ -876,12 +1292,20 @@ TextResponse objects
 
     .. attribute:: TextResponse.selector
 
-        A :class:`~scrapy.selector.Selector` instance using the response as
+        A :class:`~scrapy.Selector` instance using the response as
         target. The selector is lazily instantiated on first access.
 
+    .. autoattribute:: TextResponse.attributes
+
     :class:`TextResponse` objects support the following methods in addition to
     the standard :class:`Response` ones:
 
+    .. method:: TextResponse.jmespath(query)
+
+        A shortcut to ``TextResponse.selector.jmespath(query)``::
+
+            response.jmespath('object.[*]')
+
     .. method:: TextResponse.xpath(query)
 
         A shortcut to ``TextResponse.selector.xpath(query)``::
@@ -903,6 +1327,14 @@ TextResponse objects
         Returns a Python object from deserialized JSON document.
         The result is cached after the first call.
 
+    .. method:: TextResponse.urljoin(url)
+
+        Constructs an absolute url by combining the Response's base url with
+        a possible relative url. The base url shall be extracted from the
+        ``<base>`` tag, or just the Response's :attr:`url` if there is no such
+        tag.
+
+
 
 HtmlResponse objects
 --------------------
@@ -925,3 +1357,13 @@ XmlResponse objects
     line.  See :attr:`TextResponse.encoding`.
 
 .. _bug in lxml: https://bugs.launchpad.net/lxml/+bug/1665241
+
+JsonResponse objects
+--------------------
+
+.. class:: JsonResponse(url[, ...])
+
+    The :class:`JsonResponse` class is a subclass of :class:`TextResponse` 
+    that is used when the response has a `JSON MIME type 
+    <https://mimesniff.spec.whatwg.org/#json-mime-type>`_ in its `Content-Type` 
+    header.

docs/topics/scheduler.rst

@@ -0,0 +1,34 @@
+.. _topics-scheduler:
+
+=========
+Scheduler
+=========
+
+.. module:: scrapy.core.scheduler
+
+The scheduler component receives requests from the :ref:`engine <component-engine>`
+and stores them into persistent and/or non-persistent data structures.
+It also gets those requests and feeds them back to the engine when it
+asks for a next request to be downloaded.
+
+
+Overriding the default scheduler
+================================
+
+You can use your own custom scheduler class by supplying its full
+Python path in the :setting:`SCHEDULER` setting.
+
+
+Minimal scheduler interface
+===========================
+
+.. autoclass:: BaseScheduler
+   :members:
+
+
+Default Scrapy scheduler
+========================
+
+.. autoclass:: Scheduler
+   :members:
+   :special-members: __len__

docs/topics/settings.rst

@@ -40,8 +40,9 @@ precedence:
  1. Command line options (most precedence)
  2. Settings per-spider
  3. Project settings module
- 4. Default settings per-command
- 5. Default global settings (less precedence)
+ 4. Settings set by add-ons
+ 5. Default settings per-command
+ 6. Default global settings (less precedence)
 
 The population of these settings sources is taken care of internally, but a
 manual handling is possible using API calls. See the
@@ -66,16 +67,60 @@ Example::
 ----------------------
 
 Spiders (See the :ref:`topics-spiders` chapter for reference) can define their
-own settings that will take precedence and override the project ones. They can
-do so by setting their :attr:`~scrapy.spiders.Spider.custom_settings` attribute::
+own settings that will take precedence and override the project ones. One way
+to do so is by setting their :attr:`~scrapy.Spider.custom_settings` attribute:
+
+.. code-block:: python
+
+    import scrapy
+
 
     class MySpider(scrapy.Spider):
-        name = 'myspider'
+        name = "myspider"
 
         custom_settings = {
-            'SOME_SETTING': 'some value',
+            "SOME_SETTING": "some value",
         }
 
+It's often better to implement :meth:`~scrapy.Spider.update_settings` instead,
+and settings set there should use the "spider" priority explicitly:
+
+.. code-block:: python
+
+    import scrapy
+
+
+    class MySpider(scrapy.Spider):
+        name = "myspider"
+
+        @classmethod
+        def update_settings(cls, settings):
+            super().update_settings(settings)
+            settings.set("SOME_SETTING", "some value", priority="spider")
+
+.. versionadded:: 2.11
+
+It's also possible to modify the settings in the
+:meth:`~scrapy.Spider.from_crawler` method, e.g. based on :ref:`spider
+arguments <spiderargs>` or other logic:
+
+.. code-block:: python
+
+    import scrapy
+
+
+    class MySpider(scrapy.Spider):
+        name = "myspider"
+
+        @classmethod
+        def from_crawler(cls, crawler, *args, **kwargs):
+            spider = super().from_crawler(crawler, *args, **kwargs)
+            if "some_argument" in kwargs:
+                spider.settings.set(
+                    "SOME_SETTING", kwargs["some_argument"], priority="spider"
+                )
+            return spider
+
 3. Project settings module
 --------------------------
 
@@ -84,7 +129,13 @@ project, it's where most of your custom settings will be populated. For a
 standard Scrapy project, this means you'll be adding or changing the settings
 in the ``settings.py`` file created for your project.
 
-4. Default settings per-command
+4. Settings set by add-ons
+--------------------------
+
+:ref:`Add-ons <topics-addons>` can modify settings. They should do this with
+this priority, though this is not enforced.
+
+5. Default settings per-command
 -------------------------------
 
 Each :doc:`Scrapy tool </topics/commands>` command can have its own default
@@ -92,17 +143,21 @@ settings, which override the global default settings. Those custom command
 settings are specified in the ``default_settings`` attribute of the command
 class.
 
-5. Default global settings
+6. Default global settings
 --------------------------
 
 The global defaults are located in the ``scrapy.settings.default_settings``
 module and documented in the :ref:`topics-settings-ref` section.
 
+Compatibility with pickle
+=========================
+
+Setting values must be :ref:`picklable <pickle-picklable>`.
 
 Import paths and classes
 ========================
 
-.. versionadded:: VERSION
+.. versionadded:: 2.4.0
 
 When a setting references a callable object to be imported by Scrapy, such as a
 class or a function, there are two different ways you can specify that object:
@@ -111,14 +166,18 @@ class or a function, there are two different ways you can specify that object:
 
 -   As the object itself
 
-For example::
+For example:
+
+.. skip: next
+.. code-block:: python
 
    from mybot.pipelines.validate import ValidateMyItem
+
    ITEM_PIPELINES = {
        # passing the classname...
        ValidateMyItem: 300,
        # ...equals passing the class path
-       'mybot.pipelines.validate.ValidateMyItem': 300,
+       "mybot.pipelines.validate.ValidateMyItem": 300,
    }
 
 .. note:: Passing non-callable objects is not supported.
@@ -129,11 +188,13 @@ How to access settings
 
 .. highlight:: python
 
-In a spider, the settings are available through ``self.settings``::
+In a spider, the settings are available through ``self.settings``:
+
+.. code-block:: python
 
     class MySpider(scrapy.Spider):
-        name = 'myspider'
-        start_urls = ['http://example.com']
+        name = "myspider"
+        start_urls = ["http://example.com"]
 
         def parse(self, response):
             print(f"Existing settings: {self.settings.attributes.keys()}")
@@ -142,11 +203,13 @@ In a spider, the settings are available through ``self.settings``::
     The ``settings`` attribute is set in the base Spider class after the spider
     is initialized.  If you want to use the settings before the initialization
     (e.g., in your spider's ``__init__()`` method), you'll need to override the
-    :meth:`~scrapy.spiders.Spider.from_crawler` method.
+    :meth:`~scrapy.Spider.from_crawler` method.
 
 Settings can be accessed through the :attr:`scrapy.crawler.Crawler.settings`
 attribute of the Crawler that is passed to ``from_crawler`` method in
-extensions, middlewares and item pipelines::
+extensions, middlewares and item pipelines:
+
+.. code-block:: python
 
     class MyExtension:
         def __init__(self, log_is_enabled=False):
@@ -156,7 +219,7 @@ extensions, middlewares and item pipelines::
         @classmethod
         def from_crawler(cls, crawler):
             settings = crawler.settings
-            return cls(settings.getbool('LOG_ENABLED'))
+            return cls(settings.getbool("LOG_ENABLED"))
 
 The settings object can be used like a dict (e.g.,
 ``settings['LOG_ENABLED']``), but it's usually preferred to extract the setting
@@ -184,6 +247,16 @@ to any particular component. In that case the module of that component will be
 shown, typically an extension, middleware or pipeline. It also means that the
 component must be enabled in order for the setting to have any effect.
 
+.. setting:: ADDONS
+
+ADDONS
+------
+
+Default: ``{}``
+
+A dict containing paths to the add-ons enabled in your project and their
+priorities. For more information, see :ref:`topics-addons`.
+
 .. setting:: AWS_ACCESS_KEY_ID
 
 AWS_ACCESS_KEY_ID
@@ -204,6 +277,19 @@ Default: ``None``
 The AWS secret key used by code that requires access to `Amazon Web services`_,
 such as the :ref:`S3 feed storage backend <topics-feed-storage-s3>`.
 
+.. setting:: AWS_SESSION_TOKEN
+
+AWS_SESSION_TOKEN
+-----------------
+
+Default: ``None``
+
+The AWS security token used by code that requires access to `Amazon Web services`_,
+such as the :ref:`S3 feed storage backend <topics-feed-storage-s3>`, when using
+`temporary security credentials`_.
+
+.. _temporary security credentials: https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#temporary-access-keys
+
 .. setting:: AWS_ENDPOINT_URL
 
 AWS_ENDPOINT_URL
@@ -249,19 +335,25 @@ ASYNCIO_EVENT_LOOP
 
 Default: ``None``
 
-Import path of a given asyncio event loop class.
+Import path of a given ``asyncio`` event loop class.
 
-If the asyncio reactor is enabled (see :setting:`TWISTED_REACTOR`) this setting can be used to specify the 
-asyncio event loop to be used with it. Set the setting to the import path of the 
+If the asyncio reactor is enabled (see :setting:`TWISTED_REACTOR`) this setting can be used to specify the
+asyncio event loop to be used with it. Set the setting to the import path of the
 desired asyncio event loop class. If the setting is set to ``None`` the default asyncio
 event loop will be used.
 
 If you are installing the asyncio reactor manually using the :func:`~scrapy.utils.reactor.install_reactor`
-function, you can use the ``event_loop_path`` parameter to indicate the import path of the event loop 
-class to be used.  
+function, you can use the ``event_loop_path`` parameter to indicate the import path of the event loop
+class to be used.
 
 Note that the event loop class must inherit from :class:`asyncio.AbstractEventLoop`.
 
+.. caution:: Please be aware that, when using a non-default event loop
+    (either defined via :setting:`ASYNCIO_EVENT_LOOP` or installed with
+    :func:`~scrapy.utils.reactor.install_reactor`), Scrapy will call
+    :func:`asyncio.set_event_loop`, which will set the specified event loop
+    as the current loop for the current OS thread.
+
 .. setting:: BOT_NAME
 
 BOT_NAME
@@ -332,7 +424,7 @@ is non-zero, download delay is enforced per IP, not per domain.
 DEFAULT_ITEM_CLASS
 ------------------
 
-Default: ``'scrapy.item.Item'``
+Default: ``'scrapy.Item'``
 
 The default class that will be used for instantiating items in the :ref:`the
 Scrapy shell <topics-shell>`.
@@ -342,16 +434,23 @@ Scrapy shell <topics-shell>`.
 DEFAULT_REQUEST_HEADERS
 -----------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
-        'Accept-Language': 'en',
+        "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
+        "Accept-Language": "en",
     }
 
 The default headers used for Scrapy HTTP Requests. They're populated in the
 :class:`~scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware`.
 
+.. caution:: Cookies set via the ``Cookie`` header are not considered by the
+    :ref:`cookies-mw`. If you need to set cookies for a request, use the
+    :class:`Request.cookies <scrapy.Request>` parameter. This is a known
+    current limitation that is being worked on.
+
 .. setting:: DEPTH_LIMIT
 
 DEPTH_LIMIT
@@ -373,12 +472,15 @@ Default: ``0``
 
 Scope: ``scrapy.spidermiddlewares.depth.DepthMiddleware``
 
-An integer that is used to adjust the :attr:`~scrapy.http.Request.priority` of
-a :class:`~scrapy.http.Request` based on its depth.
+An integer that is used to adjust the :attr:`~scrapy.Request.priority` of
+a :class:`~scrapy.Request` based on its depth.
 
-The priority of a request is adjusted as follows::
+The priority of a request is adjusted as follows:
 
-    request.priority = request.priority - ( depth * DEPTH_PRIORITY )
+.. skip: next
+.. code-block:: python
+
+    request.priority = request.priority - (depth * DEPTH_PRIORITY)
 
 As depth increases, positive values of ``DEPTH_PRIORITY`` decrease request
 priority (BFO), while negative values increase request priority (DFO). See
@@ -536,7 +638,6 @@ This setting must be one of these string values:
   set this if you want the behavior of Scrapy<1.1
 - ``'TLSv1.1'``: forces TLS version 1.1
 - ``'TLSv1.2'``: forces TLS version 1.2
-- ``'SSLv3'``: forces SSL version 3 (**not recommended**)
 
 
 .. setting:: DOWNLOADER_CLIENT_TLS_VERBOSE_LOGGING
@@ -568,23 +669,25 @@ orders. For more info see :ref:`topics-downloader-middleware-setting`.
 DOWNLOADER_MIDDLEWARES_BASE
 ---------------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware': 100,
-        'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware': 300,
-        'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware': 350,
-        'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware': 400,
-        'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': 500,
-        'scrapy.downloadermiddlewares.retry.RetryMiddleware': 550,
-        'scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware': 560,
-        'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware': 580,
-        'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware': 590,
-        'scrapy.downloadermiddlewares.redirect.RedirectMiddleware': 600,
-        'scrapy.downloadermiddlewares.cookies.CookiesMiddleware': 700,
-        'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 750,
-        'scrapy.downloadermiddlewares.stats.DownloaderStats': 850,
-        'scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware': 900,
+        "scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware": 100,
+        "scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware": 300,
+        "scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware": 350,
+        "scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware": 400,
+        "scrapy.downloadermiddlewares.useragent.UserAgentMiddleware": 500,
+        "scrapy.downloadermiddlewares.retry.RetryMiddleware": 550,
+        "scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware": 560,
+        "scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware": 580,
+        "scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware": 590,
+        "scrapy.downloadermiddlewares.redirect.RedirectMiddleware": 600,
+        "scrapy.downloadermiddlewares.cookies.CookiesMiddleware": 700,
+        "scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware": 750,
+        "scrapy.downloadermiddlewares.stats.DownloaderStats": 850,
+        "scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware": 900,
     }
 
 A dict containing the downloader middlewares enabled by default in Scrapy. Low
@@ -609,24 +712,41 @@ DOWNLOAD_DELAY
 
 Default: ``0``
 
-The amount of time (in secs) that the downloader should wait before downloading
-consecutive pages from the same website. This can be used to throttle the
-crawling speed to avoid hitting servers too hard. Decimal numbers are
-supported.  Example::
+Minimum seconds to wait between 2 consecutive requests to the same domain.
 
-    DOWNLOAD_DELAY = 0.25    # 250 ms of delay
+Use :setting:`DOWNLOAD_DELAY` to throttle your crawling speed, to avoid hitting
+servers too hard.
+
+Decimal numbers are supported. For example, to send a maximum of 4 requests
+every 10 seconds::
+
+    DOWNLOAD_DELAY = 2.5
 
 This setting is also affected by the :setting:`RANDOMIZE_DOWNLOAD_DELAY`
-setting (which is enabled by default). By default, Scrapy doesn't wait a fixed
-amount of time between requests, but uses a random interval between 0.5 * :setting:`DOWNLOAD_DELAY` and 1.5 * :setting:`DOWNLOAD_DELAY`.
+setting, which is enabled by default.
 
 When :setting:`CONCURRENT_REQUESTS_PER_IP` is non-zero, delays are enforced
-per ip address instead of per domain.
+per IP address instead of per domain.
+
+Note that :setting:`DOWNLOAD_DELAY` can lower the effective per-domain
+concurrency below :setting:`CONCURRENT_REQUESTS_PER_DOMAIN`. If the response
+time of a domain is lower than :setting:`DOWNLOAD_DELAY`, the effective
+concurrency for that domain is 1. When testing throttling configurations, it
+usually makes sense to lower :setting:`CONCURRENT_REQUESTS_PER_DOMAIN` first,
+and only increase :setting:`DOWNLOAD_DELAY` once
+:setting:`CONCURRENT_REQUESTS_PER_DOMAIN` is 1 but a higher throttling is
+desired.
 
 .. _spider-download_delay-attribute:
 
-You can also change this setting per spider by setting ``download_delay``
-spider attribute.
+.. note::
+
+    This delay can be set per spider using :attr:`download_delay` spider attribute.
+
+It is also possible to change this setting per domain, although it requires
+non-trivial code. See the implementation of the :ref:`AutoThrottle
+<topics-autothrottle>` extension for an example.
+
 
 .. setting:: DOWNLOAD_HANDLERS
 
@@ -643,14 +763,17 @@ See :setting:`DOWNLOAD_HANDLERS_BASE` for example format.
 DOWNLOAD_HANDLERS_BASE
 ----------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'file': 'scrapy.core.downloader.handlers.file.FileDownloadHandler',
-        'http': 'scrapy.core.downloader.handlers.http.HTTPDownloadHandler',
-        'https': 'scrapy.core.downloader.handlers.http.HTTPDownloadHandler',
-        's3': 'scrapy.core.downloader.handlers.s3.S3DownloadHandler',
-        'ftp': 'scrapy.core.downloader.handlers.ftp.FTPDownloadHandler',
+        "data": "scrapy.core.downloader.handlers.datauri.DataURIDownloadHandler",
+        "file": "scrapy.core.downloader.handlers.file.FileDownloadHandler",
+        "http": "scrapy.core.downloader.handlers.http.HTTPDownloadHandler",
+        "https": "scrapy.core.downloader.handlers.http.HTTPDownloadHandler",
+        "s3": "scrapy.core.downloader.handlers.s3.S3DownloadHandler",
+        "ftp": "scrapy.core.downloader.handlers.ftp.FTPDownloadHandler",
     }
 
 
@@ -660,12 +783,80 @@ You should never modify this setting in your project, modify
 
 You can disable any of these download handlers by assigning ``None`` to their
 URI scheme in :setting:`DOWNLOAD_HANDLERS`. E.g., to disable the built-in FTP
-handler (without replacement), place this in your ``settings.py``::
+handler (without replacement), place this in your ``settings.py``:
+
+.. code-block:: python
 
     DOWNLOAD_HANDLERS = {
-        'ftp': None,
+        "ftp": None,
     }
 
+.. _http2:
+
+The default HTTPS handler uses HTTP/1.1. To use HTTP/2:
+
+#.  Install ``Twisted[http2]>=17.9.0`` to install the packages required to
+    enable HTTP/2 support in Twisted.
+
+#.  Update :setting:`DOWNLOAD_HANDLERS` as follows:
+
+    .. code-block:: python
+
+        DOWNLOAD_HANDLERS = {
+            "https": "scrapy.core.downloader.handlers.http2.H2DownloadHandler",
+        }
+
+.. warning::
+
+    HTTP/2 support in Scrapy is experimental, and not yet recommended for
+    production environments. Future Scrapy versions may introduce related
+    changes without a deprecation period or warning.
+
+.. note::
+
+    Known limitations of the current HTTP/2 implementation of Scrapy include:
+
+    -   No support for HTTP/2 Cleartext (h2c), since no major browser supports
+        HTTP/2 unencrypted (refer `http2 faq`_).
+
+    -   No setting to specify a maximum `frame size`_ larger than the default
+        value, 16384. Connections to servers that send a larger frame will
+        fail.
+
+    -   No support for `server pushes`_, which are ignored.
+
+    -   No support for the :signal:`bytes_received` and
+        :signal:`headers_received` signals.
+
+.. _frame size: https://tools.ietf.org/html/rfc7540#section-4.2
+.. _http2 faq: https://http2.github.io/faq/#does-http2-require-encryption
+.. _server pushes: https://tools.ietf.org/html/rfc7540#section-8.2
+
+.. setting:: DOWNLOAD_SLOTS
+
+DOWNLOAD_SLOTS
+----------------
+
+Default: ``{}``
+
+Allows to define concurrency/delay parameters on per slot (domain) basis:
+
+    .. code-block:: python
+
+        DOWNLOAD_SLOTS = {
+            "quotes.toscrape.com": {"concurrency": 1, "delay": 2, "randomize_delay": False},
+            "books.toscrape.com": {"delay": 3, "randomize_delay": False},
+        }
+
+.. note::
+
+    For other downloader slots default settings values will be used:
+
+    -   :setting:`DOWNLOAD_DELAY`: ``delay``
+    -   :setting:`CONCURRENT_REQUESTS_PER_DOMAIN`: ``concurrency``
+    -   :setting:`RANDOMIZE_DOWNLOAD_DELAY`: ``randomize_delay``
+
+
 .. setting:: DOWNLOAD_TIMEOUT
 
 DOWNLOAD_TIMEOUT
@@ -743,6 +934,15 @@ Optionally, this can be set per-request basis by using the
   If :setting:`RETRY_ENABLED` is ``True`` and this setting is set to ``True``,
   the ``ResponseFailed([_DataLoss])`` failure will be retried as usual.
 
+.. warning::
+
+    This setting is ignored by the
+    :class:`~scrapy.core.downloader.handlers.http2.H2DownloadHandler`
+    download handler (see :setting:`DOWNLOAD_HANDLERS`). In case of a data loss
+    error, the corresponding HTTP/2 connection may be corrupted, affecting other
+    requests that use the same connection; hence, a ``ResponseFailed([InvalidBodyLengthError])``
+    failure is always raised for every request that was using that connection.
+
 .. setting:: DUPEFILTER_CLASS
 
 DUPEFILTER_CLASS
@@ -752,18 +952,14 @@ Default: ``'scrapy.dupefilters.RFPDupeFilter'``
 
 The class used to detect and filter duplicate requests.
 
-The default (``RFPDupeFilter``) filters based on request fingerprint using
-the ``scrapy.utils.request.request_fingerprint`` function. In order to change
-the way duplicates are checked you could subclass ``RFPDupeFilter`` and
-override its ``request_fingerprint`` method. This method should accept
-scrapy :class:`~scrapy.http.Request` object and return its fingerprint
-(a string).
+The default (``RFPDupeFilter``) filters based on the
+:setting:`REQUEST_FINGERPRINTER_CLASS` setting.
 
 You can disable filtering of duplicate requests by setting
 :setting:`DUPEFILTER_CLASS` to ``'scrapy.dupefilters.BaseDupeFilter'``.
 Be very careful about this however, because you can get into crawling loops.
 It's usually a better idea to set the ``dont_filter`` parameter to
-``True`` on the specific :class:`~scrapy.http.Request` that should not be
+``True`` on the specific :class:`~scrapy.Request` that should not be
 filtered.
 
 .. setting:: DUPEFILTER_DEBUG
@@ -801,18 +997,20 @@ A dict containing the extensions enabled in your project, and their orders.
 EXTENSIONS_BASE
 ---------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'scrapy.extensions.corestats.CoreStats': 0,
-        'scrapy.extensions.telnet.TelnetConsole': 0,
-        'scrapy.extensions.memusage.MemoryUsage': 0,
-        'scrapy.extensions.memdebug.MemoryDebugger': 0,
-        'scrapy.extensions.closespider.CloseSpider': 0,
-        'scrapy.extensions.feedexport.FeedExporter': 0,
-        'scrapy.extensions.logstats.LogStats': 0,
-        'scrapy.extensions.spiderstate.SpiderState': 0,
-        'scrapy.extensions.throttle.AutoThrottle': 0,
+        "scrapy.extensions.corestats.CoreStats": 0,
+        "scrapy.extensions.telnet.TelnetConsole": 0,
+        "scrapy.extensions.memusage.MemoryUsage": 0,
+        "scrapy.extensions.memdebug.MemoryDebugger": 0,
+        "scrapy.extensions.closespider.CloseSpider": 0,
+        "scrapy.extensions.feedexport.FeedExporter": 0,
+        "scrapy.extensions.logstats.LogStats": 0,
+        "scrapy.extensions.spiderstate.SpiderState": 0,
+        "scrapy.extensions.throttle.AutoThrottle": 0,
     }
 
 A dict containing the extensions available by default in Scrapy, and their
@@ -822,7 +1020,6 @@ some of them need to be enabled through a setting.
 For more information See the :ref:`extensions user guide  <topics-extensions>`
 and the :ref:`list of available extensions <topics-extensions-ref>`.
 
-
 .. setting:: FEED_TEMPDIR
 
 FEED_TEMPDIR
@@ -899,11 +1096,13 @@ A dict containing the item pipelines to use, and their orders. Order values are
 arbitrary, but it is customary to define them in the 0-1000 range. Lower orders
 process before higher orders.
 
-Example::
+Example:
+
+.. code-block:: python
 
    ITEM_PIPELINES = {
-       'mybot.pipelines.validate.ValidateMyItem': 300,
-       'mybot.pipelines.validate.StoreMyItem': 800,
+       "mybot.pipelines.validate.ValidateMyItem": 300,
+       "mybot.pipelines.validate.StoreMyItem": 800,
    }
 
 .. setting:: ITEM_PIPELINES_BASE
@@ -916,6 +1115,16 @@ Default: ``{}``
 A dict containing the pipelines enabled by default in Scrapy. You should never
 modify this setting in your project, modify :setting:`ITEM_PIPELINES` instead.
 
+.. setting:: JOBDIR
+
+JOBDIR
+------
+
+Default: ``None``
+
+A string indicating the directory for storing the state of a crawl when
+:ref:`pausing and resuming crawls <topics-jobs>`.
+
 .. setting:: LOG_ENABLED
 
 LOG_ENABLED
@@ -943,6 +1152,16 @@ Default: ``None``
 
 File name to use for logging output. If ``None``, standard error will be used.
 
+.. setting:: LOG_FILE_APPEND
+
+LOG_FILE_APPEND
+---------------
+
+Default: ``True``
+
+If ``False``, the log file specified with :setting:`LOG_FILE` will be
+overwritten (discarding the output from previous runs, if any).
+
 .. setting:: LOG_FORMAT
 
 LOG_FORMAT
@@ -951,7 +1170,7 @@ LOG_FORMAT
 Default: ``'%(asctime)s [%(name)s] %(levelname)s: %(message)s'``
 
 String for formatting log messages. Refer to the
-:ref:`Python logging documentation <logrecord-attributes>` for the qwhole
+:ref:`Python logging documentation <logrecord-attributes>` for the whole
 list of available placeholders.
 
 .. setting:: LOG_DATEFORMAT
@@ -1177,20 +1396,6 @@ Adjust redirect request priority relative to original request:
 - **a positive priority adjust (default) means higher priority.**
 - a negative priority adjust means lower priority.
 
-.. setting:: RETRY_PRIORITY_ADJUST
-
-RETRY_PRIORITY_ADJUST
----------------------
-
-Default: ``-1``
-
-Scope: ``scrapy.downloadermiddlewares.retry.RetryMiddleware``
-
-Adjust retry request priority relative to original request:
-
-- a positive priority adjust means higher priority.
-- **a negative priority adjust (default) means lower priority.**
-
 .. setting:: ROBOTSTXT_OBEY
 
 ROBOTSTXT_OBEY
@@ -1238,7 +1443,8 @@ SCHEDULER
 
 Default: ``'scrapy.core.scheduler.Scheduler'``
 
-The scheduler to use for crawling.
+The scheduler class to be used for crawling.
+See the :ref:`topics-scheduler` topic for details.
 
 .. setting:: SCHEDULER_DEBUG
 
@@ -1321,12 +1527,14 @@ testing spiders. For more info see :ref:`topics-contracts`.
 SPIDER_CONTRACTS_BASE
 ---------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'scrapy.contracts.default.UrlContract' : 1,
-        'scrapy.contracts.default.ReturnsContract': 2,
-        'scrapy.contracts.default.ScrapesContract': 3,
+        "scrapy.contracts.default.UrlContract": 1,
+        "scrapy.contracts.default.ReturnsContract": 2,
+        "scrapy.contracts.default.ScrapesContract": 3,
     }
 
 A dict containing the Scrapy contracts enabled by default in Scrapy. You should
@@ -1335,10 +1543,12 @@ instead. For more info see :ref:`topics-contracts`.
 
 You can disable any of these contracts by assigning ``None`` to their class
 path in :setting:`SPIDER_CONTRACTS`. E.g., to disable the built-in
-``ScrapesContract``, place this in your ``settings.py``::
+``ScrapesContract``, place this in your ``settings.py``:
+
+.. code-block:: python
 
     SPIDER_CONTRACTS = {
-        'scrapy.contracts.default.ScrapesContract': None,
+        "scrapy.contracts.default.ScrapesContract": None,
     }
 
 .. setting:: SPIDER_LOADER_CLASS
@@ -1387,14 +1597,16 @@ orders. For more info see :ref:`topics-spider-middleware-setting`.
 SPIDER_MIDDLEWARES_BASE
 -----------------------
 
-Default::
+Default:
+
+.. code-block:: python
 
     {
-        'scrapy.spidermiddlewares.httperror.HttpErrorMiddleware': 50,
-        'scrapy.spidermiddlewares.offsite.OffsiteMiddleware': 500,
-        'scrapy.spidermiddlewares.referer.RefererMiddleware': 700,
-        'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware': 800,
-        'scrapy.spidermiddlewares.depth.DepthMiddleware': 900,
+        "scrapy.spidermiddlewares.httperror.HttpErrorMiddleware": 50,
+        "scrapy.spidermiddlewares.offsite.OffsiteMiddleware": 500,
+        "scrapy.spidermiddlewares.referer.RefererMiddleware": 700,
+        "scrapy.spidermiddlewares.urllength.UrlLengthMiddleware": 800,
+        "scrapy.spidermiddlewares.depth.DepthMiddleware": 900,
     }
 
 A dict containing the spider middlewares enabled by default in Scrapy, and
@@ -1410,9 +1622,11 @@ Default: ``[]``
 
 A list of modules where Scrapy will look for spiders.
 
-Example::
+Example:
 
-    SPIDER_MODULES = ['mybot.spiders_prod', 'mybot.spiders_dev']
+.. code-block:: python
+
+    SPIDER_MODULES = ["mybot.spiders_prod", "mybot.spiders_dev"]
 
 .. setting:: STATS_CLASS
 
@@ -1496,73 +1710,83 @@ If a reactor is already installed,
 
 :meth:`CrawlerRunner.__init__ <scrapy.crawler.CrawlerRunner.__init__>` raises
 :exc:`Exception` if the installed reactor does not match the
-:setting:`TWISTED_REACTOR` setting; therfore, having top-level
+:setting:`TWISTED_REACTOR` setting; therefore, having top-level
 :mod:`~twisted.internet.reactor` imports in project files and imported
 third-party libraries will make Scrapy raise :exc:`Exception` when
 it checks which reactor is installed.
 
-In order to use the reactor installed by Scrapy::
+In order to use the reactor installed by Scrapy:
+
+.. code-block:: python
 
     import scrapy
     from twisted.internet import reactor
 
 
     class QuotesSpider(scrapy.Spider):
-        name = 'quotes'
+        name = "quotes"
 
         def __init__(self, *args, **kwargs):
-            self.timeout = int(kwargs.pop('timeout', '60'))
+            self.timeout = int(kwargs.pop("timeout", "60"))
             super(QuotesSpider, self).__init__(*args, **kwargs)
 
         def start_requests(self):
             reactor.callLater(self.timeout, self.stop)
 
-            urls = ['http://quotes.toscrape.com/page/1']
+            urls = ["https://quotes.toscrape.com/page/1"]
             for url in urls:
                 yield scrapy.Request(url=url, callback=self.parse)
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
-                yield {'text': quote.css('span.text::text').get()}
+            for quote in response.css("div.quote"):
+                yield {"text": quote.css("span.text::text").get()}
 
         def stop(self):
-            self.crawler.engine.close_spider(self, 'timeout')
+            self.crawler.engine.close_spider(self, "timeout")
 
 
-which raises :exc:`Exception`, becomes::
+which raises :exc:`Exception`, becomes:
+
+.. code-block:: python
 
     import scrapy
 
 
     class QuotesSpider(scrapy.Spider):
-        name = 'quotes'
+        name = "quotes"
 
         def __init__(self, *args, **kwargs):
-            self.timeout = int(kwargs.pop('timeout', '60'))
+            self.timeout = int(kwargs.pop("timeout", "60"))
             super(QuotesSpider, self).__init__(*args, **kwargs)
 
         def start_requests(self):
             from twisted.internet import reactor
+
             reactor.callLater(self.timeout, self.stop)
 
-            urls = ['http://quotes.toscrape.com/page/1']
+            urls = ["https://quotes.toscrape.com/page/1"]
             for url in urls:
                 yield scrapy.Request(url=url, callback=self.parse)
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
-                yield {'text': quote.css('span.text::text').get()}
+            for quote in response.css("div.quote"):
+                yield {"text": quote.css("span.text::text").get()}
 
         def stop(self):
-            self.crawler.engine.close_spider(self, 'timeout')
+            self.crawler.engine.close_spider(self, "timeout")
 
 
 The default value of the :setting:`TWISTED_REACTOR` setting is ``None``, which
-means that Scrapy will not attempt to install any specific reactor, and the
-default reactor defined by Twisted for the current platform will be used. This
+means that Scrapy will use the existing reactor if one is already installed, or
+install the default reactor defined by Twisted for the current platform. This
 is to maintain backward compatibility and avoid possible problems caused by
 using a non-default reactor.
 
+.. versionchanged:: 2.7
+   The :command:`startproject` command now sets this setting to
+   ``twisted.internet.asyncioreactor.AsyncioSelectorReactor`` in the generated
+   ``settings.py`` file.
+
 For additional information, see :doc:`core/howto/choosing-reactor`.
 
 
@@ -1575,8 +1799,19 @@ Default: ``2083``
 
 Scope: ``spidermiddlewares.urllength``
 
-The maximum URL length to allow for crawled URLs. For more information about
-the default value for this setting see: https://boutell.com/newfaq/misc/urllength.html
+The maximum URL length to allow for crawled URLs.
+
+This setting can act as a stopping condition in case of URLs of ever-increasing
+length, which may be caused for example by a programming error either in the
+target server or in your code. See also :setting:`REDIRECT_MAX_TIMES` and
+:setting:`DEPTH_LIMIT`.
+
+Use ``0`` to allow URLs of any length.
+
+The default value is copied from the `Microsoft Internet Explorer maximum URL
+length`_, even though this setting exists for different reasons.
+
+.. _Microsoft Internet Explorer maximum URL length: https://support.microsoft.com/en-us/topic/maximum-url-length-is-2-083-characters-in-internet-explorer-174e7c8a-6666-f4e0-6fd6-908b53c12246
 
 .. setting:: USER_AGENT
 
@@ -1588,7 +1823,7 @@ Default: ``"Scrapy/VERSION (+https://scrapy.org)"``
 The default User-Agent to use when crawling, unless overridden. This user agent is
 also used by :class:`~scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware`
 if :setting:`ROBOTSTXT_USER_AGENT` setting is ``None`` and
-there is no overridding User-Agent header specified for the request.
+there is no overriding User-Agent header specified for the request.
 
 
 Settings documented elsewhere:
@@ -1599,7 +1834,6 @@ case to see how to enable and use them.
 
 .. settingslist::
 
-
 .. _Amazon web services: https://aws.amazon.com/
 .. _breadth-first order: https://en.wikipedia.org/wiki/Breadth-first_search
 .. _depth-first order: https://en.wikipedia.org/wiki/Depth-first_search

docs/topics/shell.rst

@@ -95,20 +95,21 @@ convenience.
 Available Shortcuts
 -------------------
 
- * ``shelp()`` - print a help with the list of available objects and shortcuts
+-   ``shelp()`` - print a help with the list of available objects and
+    shortcuts
 
- * ``fetch(url[, redirect=True])`` - fetch a new response from the given
-   URL and update all related objects accordingly. You can optionaly ask for
-   HTTP 3xx redirections to not be followed by passing ``redirect=False``
+-   ``fetch(url[, redirect=True])`` - fetch a new response from the given URL
+    and update all related objects accordingly. You can optionally ask for HTTP
+    3xx redirections to not be followed by passing ``redirect=False``
 
- * ``fetch(request)`` - fetch a new response from the given request and
-   update all related objects accordingly.
+-   ``fetch(request)`` - fetch a new response from the given request and update
+    all related objects accordingly.
 
- * ``view(response)`` - open the given response in your local web browser, for
-   inspection. This will add a `\<base\> tag`_ to the response body in order
-   for external links (such as images and style sheets) to display properly.
-   Note, however, that this will create a temporary file in your computer,
-   which won't be removed automatically.
+-   ``view(response)`` - open the given response in your local web browser, for
+    inspection. This will add a `\<base\> tag`_ to the response body in order
+    for external links (such as images and style sheets) to display properly.
+    Note, however, that this will create a temporary file in your computer,
+    which won't be removed automatically.
 
 .. _<base> tag: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
 
@@ -117,26 +118,26 @@ Available Scrapy objects
 
 The Scrapy shell automatically creates some convenient objects from the
 downloaded page, like the :class:`~scrapy.http.Response` object and the
-:class:`~scrapy.selector.Selector` objects (for both HTML and XML
+:class:`~scrapy.Selector` objects (for both HTML and XML
 content).
 
 Those objects are:
 
- * ``crawler`` - the current :class:`~scrapy.crawler.Crawler` object.
+-    ``crawler`` - the current :class:`~scrapy.crawler.Crawler` object.
 
- * ``spider`` - the Spider which is known to handle the URL, or a
-   :class:`~scrapy.spiders.Spider` object if there is no spider found for
-   the current URL
+-   ``spider`` - the Spider which is known to handle the URL, or a
+    :class:`~scrapy.Spider` object if there is no spider found for the
+    current URL
 
- * ``request`` - a :class:`~scrapy.http.Request` object of the last fetched
-   page. You can modify this request using :meth:`~scrapy.http.Request.replace`
-   or fetch a new request (without leaving the shell) using the ``fetch``
-   shortcut.
+-   ``request`` - a :class:`~scrapy.Request` object of the last fetched
+    page. You can modify this request using
+    :meth:`~scrapy.Request.replace` or fetch a new request (without
+    leaving the shell) using the ``fetch`` shortcut.
 
- * ``response`` - a :class:`~scrapy.http.Response` object containing the last
-   fetched page
+-   ``response`` - a :class:`~scrapy.http.Response` object containing the last
+    fetched page
 
- * ``settings`` - the current :ref:`Scrapy settings <topics-settings>`
+-   ``settings`` - the current :ref:`Scrapy settings <topics-settings>`
 
 Example of shell session
 ========================
@@ -190,44 +191,46 @@ all start with the ``[s]`` prefix)::
 
 After that, we can start playing with the objects:
 
->>> response.xpath('//title/text()').get()
-'Scrapy | A Fast and Powerful Scraping and Web Crawling Framework'
+.. code-block:: pycon
 
->>> fetch("https://old.reddit.com/")
+    >>> response.xpath("//title/text()").get()
+    'Scrapy | A Fast and Powerful Scraping and Web Crawling Framework'
 
->>> response.xpath('//title/text()').get()
-'reddit: the front page of the internet'
+    >>> fetch("https://old.reddit.com/")
 
->>> request = request.replace(method="POST")
+    >>> response.xpath("//title/text()").get()
+    'reddit: the front page of the internet'
 
->>> fetch(request)
+    >>> request = request.replace(method="POST")
 
->>> response.status
-404
+    >>> fetch(request)
 
->>> from pprint import pprint
+    >>> response.status
+    404
 
->>> pprint(response.headers)
-{'Accept-Ranges': ['bytes'],
- 'Cache-Control': ['max-age=0, must-revalidate'],
- 'Content-Type': ['text/html; charset=UTF-8'],
- 'Date': ['Thu, 08 Dec 2016 16:21:19 GMT'],
- 'Server': ['snooserv'],
- 'Set-Cookie': ['loid=KqNLou0V9SKMX4qb4n; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
-                'loidcreated=2016-12-08T16%3A21%3A19.445Z; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
-                'loid=vi0ZVe4NkxNWdlH7r7; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
-                'loidcreated=2016-12-08T16%3A21%3A19.459Z; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure'],
- 'Vary': ['accept-encoding'],
- 'Via': ['1.1 varnish'],
- 'X-Cache': ['MISS'],
- 'X-Cache-Hits': ['0'],
- 'X-Content-Type-Options': ['nosniff'],
- 'X-Frame-Options': ['SAMEORIGIN'],
- 'X-Moose': ['majestic'],
- 'X-Served-By': ['cache-cdg8730-CDG'],
- 'X-Timer': ['S1481214079.394283,VS0,VE159'],
- 'X-Ua-Compatible': ['IE=edge'],
- 'X-Xss-Protection': ['1; mode=block']}
+    >>> from pprint import pprint
+
+    >>> pprint(response.headers)
+    {'Accept-Ranges': ['bytes'],
+    'Cache-Control': ['max-age=0, must-revalidate'],
+    'Content-Type': ['text/html; charset=UTF-8'],
+    'Date': ['Thu, 08 Dec 2016 16:21:19 GMT'],
+    'Server': ['snooserv'],
+    'Set-Cookie': ['loid=KqNLou0V9SKMX4qb4n; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
+                    'loidcreated=2016-12-08T16%3A21%3A19.445Z; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
+                    'loid=vi0ZVe4NkxNWdlH7r7; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure',
+                    'loidcreated=2016-12-08T16%3A21%3A19.459Z; Domain=reddit.com; Max-Age=63071999; Path=/; expires=Sat, 08-Dec-2018 16:21:19 GMT; secure'],
+    'Vary': ['accept-encoding'],
+    'Via': ['1.1 varnish'],
+    'X-Cache': ['MISS'],
+    'X-Cache-Hits': ['0'],
+    'X-Content-Type-Options': ['nosniff'],
+    'X-Frame-Options': ['SAMEORIGIN'],
+    'X-Moose': ['majestic'],
+    'X-Served-By': ['cache-cdg8730-CDG'],
+    'X-Timer': ['S1481214079.394283,VS0,VE159'],
+    'X-Ua-Compatible': ['IE=edge'],
+    'X-Xss-Protection': ['1; mode=block']}
 
 
 .. _topics-shell-inspect-response:
@@ -241,7 +244,9 @@ getting there.
 
 This can be achieved by using the ``scrapy.shell.inspect_response`` function.
 
-Here's an example of how you would call it from your spider::
+Here's an example of how you would call it from your spider:
+
+.. code-block:: python
 
     import scrapy
 
@@ -258,6 +263,7 @@ Here's an example of how you would call it from your spider::
             # We want to inspect one specific response.
             if ".org" in response.url:
                 from scrapy.shell import inspect_response
+
                 inspect_response(response, self)
 
             # Rest of parsing code.
@@ -275,14 +281,18 @@ When you run the spider, you will get something similar to this::
 
 Then, you can check if the extraction code is working:
 
->>> response.xpath('//h1[@class="fn"]')
-[]
+.. code-block:: pycon
+
+    >>> response.xpath('//h1[@class="fn"]')
+    []
 
 Nope, it doesn't. So you can open the response in your web browser and see if
 it's the response you were expecting:
 
->>> view(response)
-True
+.. code-block:: pycon
+
+    >>> view(response)
+    True
 
 Finally you hit Ctrl-D (or Ctrl-Z in Windows) to exit the shell and resume the
 crawling::

docs/topics/signals.rst

@@ -16,7 +16,9 @@ deliver the arguments that the handler receives.
 You can connect to signals (or send your own) through the
 :ref:`topics-api-signals`.
 
-Here is a simple example showing how you can catch signals and perform some action::
+Here is a simple example showing how you can catch signals and perform some action:
+
+.. code-block:: python
 
     from scrapy import signals
     from scrapy import Spider
@@ -30,17 +32,14 @@ Here is a simple example showing how you can catch signals and perform some acti
             "http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/",
         ]
 
-
         @classmethod
         def from_crawler(cls, crawler, *args, **kwargs):
             spider = super(DmozSpider, cls).from_crawler(crawler, *args, **kwargs)
             crawler.signals.connect(spider.spider_closed, signal=signals.spider_closed)
             return spider
 
-
         def spider_closed(self, spider):
-            spider.logger.info('Spider closed: %s', spider.name)
-
+            spider.logger.info("Spider closed: %s", spider.name)
 
         def parse(self, response):
             pass
@@ -51,16 +50,21 @@ Deferred signal handlers
 ========================
 
 Some signals support returning :class:`~twisted.internet.defer.Deferred`
-objects from their handlers, allowing you to run asynchronous code that
-does not block Scrapy. If a signal handler returns a
-:class:`~twisted.internet.defer.Deferred`, Scrapy waits for that
-:class:`~twisted.internet.defer.Deferred` to fire.
+or :term:`awaitable objects <awaitable>` from their handlers, allowing
+you to run asynchronous code that does not block Scrapy. If a signal
+handler returns one of these objects, Scrapy waits for that asynchronous
+operation to finish.
+
+Let's take an example using :ref:`coroutines <topics-coroutines>`:
+
+.. code-block:: python
+
+    import scrapy
 
-Let's take an example::
 
     class SignalSpider(scrapy.Spider):
-        name = 'signals'
-        start_urls = ['http://quotes.toscrape.com/page/1/']
+        name = "signals"
+        start_urls = ["https://quotes.toscrape.com/page/1/"]
 
         @classmethod
         def from_crawler(cls, crawler, *args, **kwargs):
@@ -68,28 +72,26 @@ Let's take an example::
             crawler.signals.connect(spider.item_scraped, signal=signals.item_scraped)
             return spider
 
-        def item_scraped(self, item):
+        async def item_scraped(self, item):
             # Send the scraped item to the server
-            d = treq.post(
-                'http://example.com/post',
-                json.dumps(item).encode('ascii'),
-                headers={b'Content-Type': [b'application/json']}
+            response = await treq.post(
+                "http://example.com/post",
+                json.dumps(item).encode("ascii"),
+                headers={b"Content-Type": [b"application/json"]},
             )
 
-            # The next item will be scraped only after
-            # deferred (d) is fired
-            return d
+            return response
 
         def parse(self, response):
-            for quote in response.css('div.quote'):
+            for quote in response.css("div.quote"):
                 yield {
-                    'text': quote.css('span.text::text').get(),
-                    'author': quote.css('small.author::text').get(),
-                    'tags': quote.css('div.tags a.tag::text').getall(),
+                    "text": quote.css("span.text::text").get(),
+                    "author": quote.css("small.author::text").get(),
+                    "tags": quote.css("div.tags a.tag::text").getall(),
                 }
 
 See the :ref:`topics-signals-ref` below to know which signals support
-:class:`~twisted.internet.defer.Deferred`.
+:class:`~twisted.internet.defer.Deferred` and :term:`awaitable objects <awaitable>`.
 
 .. _topics-signals-ref:
 
@@ -155,7 +157,7 @@ item_scraped
     :type item: :ref:`item object <item-types>`
 
     :param spider: the spider which scraped the item
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
     :param response: the response from where the item was scraped
     :type response: :class:`~scrapy.http.Response` object
@@ -175,7 +177,7 @@ item_dropped
     :type item: :ref:`item object <item-types>`
 
     :param spider: the spider which scraped the item
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
     :param response: the response from where the item was dropped
     :type response: :class:`~scrapy.http.Response` object
@@ -203,7 +205,7 @@ item_error
     :type response: :class:`~scrapy.http.Response` object
 
     :param spider: the spider which raised the exception
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
     :param failure: the exception raised
     :type failure: twisted.python.failure.Failure
@@ -223,7 +225,7 @@ spider_closed
     This signal supports returning deferreds from its handlers.
 
     :param spider: the spider which has been closed
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
     :param reason: a string which describes the reason why the spider was closed. If
         it was closed because the spider has completed scraping, the reason
@@ -247,7 +249,7 @@ spider_opened
     This signal supports returning deferreds from its handlers.
 
     :param spider: the spider which has been opened
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 spider_idle
 ~~~~~~~~~~~
@@ -268,10 +270,17 @@ spider_idle
     You may raise a :exc:`~scrapy.exceptions.DontCloseSpider` exception to
     prevent the spider from being closed.
 
+    Alternatively, you may raise a :exc:`~scrapy.exceptions.CloseSpider`
+    exception to provide a custom spider closing reason. An
+    idle handler is the perfect place to put some code that assesses
+    the final spider results and update the final closing reason
+    accordingly (e.g. setting it to 'too_few_results' instead of
+    'finished').
+
     This signal does not support returning deferreds from its handlers.
 
     :param spider: the spider which has gone idle
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 .. note:: Scheduling some requests in your :signal:`spider_idle` handler does
     **not** guarantee that it can prevent the spider from being closed,
@@ -296,7 +305,34 @@ spider_error
     :type response: :class:`~scrapy.http.Response` object
 
     :param spider: the spider which raised the exception
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
+
+feed_slot_closed
+~~~~~~~~~~~~~~~~
+
+.. signal:: feed_slot_closed
+.. function:: feed_slot_closed(slot)
+
+    Sent when a :ref:`feed exports <topics-feed-exports>` slot is closed.
+
+    This signal supports returning deferreds from its handlers.
+
+    :param slot: the slot closed
+    :type slot: scrapy.extensions.feedexport.FeedSlot
+
+
+feed_exporter_closed
+~~~~~~~~~~~~~~~~~~~~
+
+.. signal:: feed_exporter_closed
+.. function:: feed_exporter_closed()
+
+    Sent when the :ref:`feed exports <topics-feed-exports>` extension is closed,
+    during the handling of the :signal:`spider_closed` signal by the extension,
+    after all feed exporting has been handled.
+
+    This signal supports returning deferreds from its handlers.
+
 
 Request signals
 ---------------
@@ -307,16 +343,16 @@ request_scheduled
 .. signal:: request_scheduled
 .. function:: request_scheduled(request, spider)
 
-    Sent when the engine schedules a :class:`~scrapy.http.Request`, to be
+    Sent when the engine schedules a :class:`~scrapy.Request`, to be
     downloaded later.
 
     This signal does not support returning deferreds from its handlers.
 
     :param request: the request that reached the scheduler
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider that yielded the request
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 request_dropped
 ~~~~~~~~~~~~~~~
@@ -324,16 +360,16 @@ request_dropped
 .. signal:: request_dropped
 .. function:: request_dropped(request, spider)
 
-    Sent when a :class:`~scrapy.http.Request`, scheduled by the engine to be
+    Sent when a :class:`~scrapy.Request`, scheduled by the engine to be
     downloaded later, is rejected by the scheduler.
 
     This signal does not support returning deferreds from its handlers.
 
     :param request: the request that reached the scheduler
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider that yielded the request
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 request_reached_downloader
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -341,15 +377,15 @@ request_reached_downloader
 .. signal:: request_reached_downloader
 .. function:: request_reached_downloader(request, spider)
 
-    Sent when a :class:`~scrapy.http.Request` reached downloader.
+    Sent when a :class:`~scrapy.Request` reached downloader.
 
     This signal does not support returning deferreds from its handlers.
 
     :param request: the request that reached downloader
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider that yielded the request
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 request_left_downloader
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -359,16 +395,16 @@ request_left_downloader
 
     .. versionadded:: 2.0
 
-    Sent when a :class:`~scrapy.http.Request` leaves the downloader, even in case of
+    Sent when a :class:`~scrapy.Request` leaves the downloader, even in case of
     failure.
 
     This signal does not support returning deferreds from its handlers.
 
     :param request: the request that reached the downloader
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider that yielded the request
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 bytes_received
 ~~~~~~~~~~~~~~
@@ -384,22 +420,52 @@ bytes_received
     a possible scenario for a 25 kb response would be two signals fired
     with 10 kb of data, and a final one with 5 kb of data.
 
+    Handlers for this signal can stop the download of a response while it
+    is in progress by raising the :exc:`~scrapy.exceptions.StopDownload`
+    exception. Please refer to the :ref:`topics-stop-response-download` topic
+    for additional information and examples.
+
     This signal does not support returning deferreds from its handlers.
 
     :param data: the data received by the download handler
     :type data: :class:`bytes` object
 
     :param request: the request that generated the download
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider associated with the response
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
-.. note:: Handlers of this signal can stop the download of a response while it
+headers_received
+~~~~~~~~~~~~~~~~
+
+.. versionadded:: 2.5
+
+.. signal:: headers_received
+.. function:: headers_received(headers, body_length, request, spider)
+
+    Sent by the HTTP 1.1 and S3 download handlers when the response headers are
+    available for a given request, before downloading any additional content.
+
+    Handlers for this signal can stop the download of a response while it
     is in progress by raising the :exc:`~scrapy.exceptions.StopDownload`
     exception. Please refer to the :ref:`topics-stop-response-download` topic
     for additional information and examples.
 
+    This signal does not support returning deferreds from its handlers.
+
+    :param headers: the headers received by the download handler
+    :type headers: :class:`scrapy.http.headers.Headers` object
+
+    :param body_length: expected size of the response body, in bytes
+    :type body_length: `int`
+
+    :param request: the request that generated the download
+    :type request: :class:`~scrapy.Request` object
+
+    :param spider: the spider associated with the response
+    :type spider: :class:`~scrapy.Spider` object
+
 Response signals
 ----------------
 
@@ -418,10 +484,10 @@ response_received
     :type response: :class:`~scrapy.http.Response` object
 
     :param request: the request that generated the response
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider for which the response is intended
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object
 
 .. note:: The ``request`` argument might not contain the original request that
     reached the downloader, if a :ref:`topics-downloader-middleware` modifies
@@ -442,7 +508,7 @@ response_downloaded
     :type response: :class:`~scrapy.http.Response` object
 
     :param request: the request that generated the response
-    :type request: :class:`~scrapy.http.Request` object
+    :type request: :class:`~scrapy.Request` object
 
     :param spider: the spider for which the response is intended
-    :type spider: :class:`~scrapy.spiders.Spider` object
+    :type spider: :class:`~scrapy.Spider` object

docs/topics/spider-middleware.rst

@@ -18,10 +18,12 @@ To activate a spider middleware component, add it to the
 :setting:`SPIDER_MIDDLEWARES` setting, which is a dict whose keys are the
 middleware class path and their values are the middleware orders.
 
-Here's an example::
+Here's an example:
+
+.. code-block:: python
 
     SPIDER_MIDDLEWARES = {
-        'myproject.middlewares.CustomSpiderMiddleware': 543,
+        "myproject.middlewares.CustomSpiderMiddleware": 543,
     }
 
 The :setting:`SPIDER_MIDDLEWARES` setting is merged with the
@@ -44,11 +46,13 @@ previous (or subsequent) middleware being applied.
 If you want to disable a builtin middleware (the ones defined in
 :setting:`SPIDER_MIDDLEWARES_BASE`, and enabled by default) you must define it
 in your project :setting:`SPIDER_MIDDLEWARES` setting and assign ``None`` as its
-value.  For example, if you want to disable the off-site middleware::
+value.  For example, if you want to disable the off-site middleware:
+
+.. code-block:: python
 
     SPIDER_MIDDLEWARES = {
-        'myproject.middlewares.CustomSpiderMiddleware': 543,
-        'scrapy.spidermiddlewares.offsite.OffsiteMiddleware': None,
+        "myproject.middlewares.CustomSpiderMiddleware": 543,
+        "scrapy.spidermiddlewares.offsite.OffsiteMiddleware": None,
     }
 
 Finally, keep in mind that some middlewares may need to be enabled through a
@@ -93,7 +97,7 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
         :type response: :class:`~scrapy.http.Response` object
 
         :param spider: the spider for which this response is intended
-        :type spider: :class:`~scrapy.spiders.Spider` object
+        :type spider: :class:`~scrapy.Spider` object
 
 
     .. method:: process_spider_output(response, result, spider)
@@ -102,19 +106,39 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
         it has processed the response.
 
         :meth:`process_spider_output` must return an iterable of
-        :class:`~scrapy.http.Request` objects and :ref:`item object
+        :class:`~scrapy.Request` objects and :ref:`item objects
         <topics-items>`.
 
+        .. versionchanged:: 2.7
+           This method may be defined as an :term:`asynchronous generator`, in
+           which case ``result`` is an :term:`asynchronous iterable`.
+
+        Consider defining this method as an :term:`asynchronous generator`,
+        which will be a requirement in a future version of Scrapy. However, if
+        you plan on sharing your spider middleware with other people, consider
+        either :ref:`enforcing Scrapy 2.7 <enforce-component-requirements>`
+        as a minimum requirement of your spider middleware, or :ref:`making
+        your spider middleware universal <universal-spider-middleware>` so that
+        it works with Scrapy versions earlier than Scrapy 2.7.
+
         :param response: the response which generated this output from the
           spider
         :type response: :class:`~scrapy.http.Response` object
 
         :param result: the result returned by the spider
-        :type result: an iterable of :class:`~scrapy.http.Request` objects and
-          :ref:`item object <topics-items>`
+        :type result: an iterable of :class:`~scrapy.Request` objects and
+          :ref:`item objects <topics-items>`
 
         :param spider: the spider whose result is being processed
-        :type spider: :class:`~scrapy.spiders.Spider` object
+        :type spider: :class:`~scrapy.Spider` object
+
+    .. method:: process_spider_output_async(response, result, spider)
+
+        .. versionadded:: 2.7
+
+        If defined, this method must be an :term:`asynchronous generator`,
+        which will be called instead of :meth:`process_spider_output` if
+        ``result`` is an :term:`asynchronous iterable`.
 
     .. method:: process_spider_exception(response, exception, spider)
 
@@ -122,8 +146,8 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
         method (from a previous spider middleware) raises an exception.
 
         :meth:`process_spider_exception` should return either ``None`` or an
-        iterable of :class:`~scrapy.http.Request` objects and :ref:`item object
-        <topics-items>`.
+        iterable of :class:`~scrapy.Request` or :ref:`item <topics-items>`
+        objects.
 
         If it returns ``None``, Scrapy will continue processing this exception,
         executing any other :meth:`process_spider_exception` in the following
@@ -142,7 +166,7 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
         :type exception: :exc:`Exception` object
 
         :param spider: the spider which raised the exception
-        :type spider: :class:`~scrapy.spiders.Spider` object
+        :type spider: :class:`~scrapy.Spider` object
 
     .. method:: process_start_requests(start_requests, spider)
 
@@ -152,7 +176,7 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
         items).
 
         It receives an iterable (in the ``start_requests`` parameter) and must
-        return another iterable of :class:`~scrapy.http.Request` objects.
+        return another iterable of :class:`~scrapy.Request` objects.
 
         .. note:: When implementing this method in your spider middleware, you
            should always return an iterable (that follows the input one) and
@@ -164,10 +188,10 @@ object gives you access, for example, to the :ref:`settings <topics-settings>`.
            (like a time limit or item/page count).
 
         :param start_requests: the start requests
-        :type start_requests: an iterable of :class:`~scrapy.http.Request`
+        :type start_requests: an iterable of :class:`~scrapy.Request`
 
         :param spider: the spider to whom the start requests belong
-        :type spider: :class:`~scrapy.spiders.Spider` object
+        :type spider: :class:`~scrapy.Spider` object
 
     .. method:: from_crawler(cls, crawler)
 
@@ -241,7 +265,12 @@ specify which response codes the spider is able to handle using the
 :setting:`HTTPERROR_ALLOWED_CODES` setting.
 
 For example, if you want your spider to handle 404 responses you can do
-this::
+this:
+
+.. code-block:: python
+
+    from scrapy.spiders import CrawlSpider
+
 
     class MySpider(CrawlSpider):
         handle_httpstatus_list = [404]
@@ -251,9 +280,10 @@ this::
 .. reqmeta:: handle_httpstatus_all
 
 The ``handle_httpstatus_list`` key of :attr:`Request.meta
-<scrapy.http.Request.meta>` can also be used to specify which response codes to
+<scrapy.Request.meta>` can also be used to specify which response codes to
 allow on a per-request basis. You can also set the meta key ``handle_httpstatus_all``
-to ``True`` if you want to allow any response code for a request.
+to ``True`` if you want to allow any response code for a request, and ``False`` to
+disable the effects of the ``handle_httpstatus_all`` key.
 
 Keep in mind, however, that it's usually a bad idea to handle non-200
 responses, unless you really know what you're doing.
@@ -294,7 +324,7 @@ OffsiteMiddleware
    Filters out Requests for URLs outside the domains covered by the spider.
 
    This middleware filters out every request whose host names aren't in the
-   spider's :attr:`~scrapy.spiders.Spider.allowed_domains` attribute.
+   spider's :attr:`~scrapy.Spider.allowed_domains` attribute.
    All subdomains of any domain in the list are also allowed.
    E.g. the rule ``www.example.org`` will also allow ``bob.www.example.org``
    but not ``www2.example.com`` nor ``example.com``.
@@ -312,10 +342,10 @@ OffsiteMiddleware
    will be printed (but only for the first request filtered).
 
    If the spider doesn't define an
-   :attr:`~scrapy.spiders.Spider.allowed_domains` attribute, or the
+   :attr:`~scrapy.Spider.allowed_domains` attribute, or the
    attribute is empty, the offsite middleware will allow all requests.
 
-   If the request has the :attr:`~scrapy.http.Request.dont_filter` attribute
+   If the request has the :attr:`~scrapy.Request.dont_filter` attribute
    set, the offsite middleware will allow the request even if its domain is not
    listed in allowed domains.
 
@@ -439,4 +469,3 @@ UrlLengthMiddleware
    settings (see the settings documentation for more info):
 
       * :setting:`URLLENGTH_LIMIT` - The maximum URL length to allow for crawled URLs.
-

docs/topics/spiders.rst

@@ -17,15 +17,15 @@ For spiders, the scraping cycle goes through something like this:
    those requests.
 
    The first requests to perform are obtained by calling the
-   :meth:`~scrapy.spiders.Spider.start_requests` method which (by default)
-   generates :class:`~scrapy.http.Request` for the URLs specified in the
-   :attr:`~scrapy.spiders.Spider.start_urls` and the
-   :attr:`~scrapy.spiders.Spider.parse` method as callback function for the
+   :meth:`~scrapy.Spider.start_requests` method which (by default)
+   generates :class:`~scrapy.Request` for the URLs specified in the
+   :attr:`~scrapy.Spider.start_urls` and the
+   :attr:`~scrapy.Spider.parse` method as callback function for the
    Requests.
 
 2. In the callback function, you parse the response (web page) and return
    :ref:`item objects <topics-items>`,
-   :class:`~scrapy.http.Request` objects, or an iterable of these objects.
+   :class:`~scrapy.Request` objects, or an iterable of these objects.
    Those Requests will also contain a callback (maybe
    the same) and will then be downloaded by Scrapy and then their
    response handled by the specified callback.
@@ -42,15 +42,13 @@ Even though this cycle applies (more or less) to any kind of spider, there are
 different kinds of default spiders bundled into Scrapy for different purposes.
 We will talk about those types here.
 
-.. module:: scrapy.spiders
-   :synopsis: Spiders base class, spider manager and spider middleware
-
 .. _topics-spiders-ref:
 
 scrapy.Spider
 =============
 
-.. class:: Spider()
+.. class:: scrapy.spiders.Spider
+.. class:: scrapy.Spider()
 
    This is the simplest spider, and the one from which every other spider
    must inherit (including spiders that come bundled with Scrapy, as well as spiders
@@ -86,7 +84,7 @@ scrapy.Spider
 
        A list of URLs where the spider will begin to crawl from, when no
        particular URLs are specified. So, the first pages downloaded will be those
-       listed here. The subsequent :class:`~scrapy.http.Request` will be generated successively from data
+       listed here. The subsequent :class:`~scrapy.Request` will be generated successively from data
        contained in the start URLs.
 
    .. attribute:: custom_settings
@@ -101,7 +99,7 @@ scrapy.Spider
    .. attribute:: crawler
 
       This attribute is set by the :meth:`from_crawler` class method after
-      initializating the class, and links to the
+      initializing the class, and links to the
       :class:`~scrapy.crawler.Crawler` object to which this spider instance is
       bound.
 
@@ -121,6 +119,11 @@ scrapy.Spider
       send log messages through it as described on
       :ref:`topics-logging-from-spiders`.
 
+   .. attribute:: state
+
+      A dict you can use to persist some spider state between batches.
+      See :ref:`topics-keeping-persistent-state-between-batches` to know more about it.
+
    .. method:: from_crawler(crawler, *args, **kwargs)
 
        This is the class method used by Scrapy to create your spiders.
@@ -133,6 +136,21 @@ scrapy.Spider
        attributes in the new instance so they can be accessed later inside the
        spider's code.
 
+       .. versionchanged:: 2.11
+
+           The settings in ``crawler.settings`` can now be modified in this
+           method, which is handy if you want to modify them based on
+           arguments. As a consequence, these settings aren't the final values
+           as they can be modified later by e.g. :ref:`add-ons
+           <topics-addons>`. For the same reason, most of the
+           :class:`~scrapy.crawler.Crawler` attributes aren't initialized at
+           this point.
+
+           The final settings and the initialized
+           :class:`~scrapy.crawler.Crawler` attributes are available in the
+           :meth:`start_requests` method, handlers of the
+           :signal:`engine_started` signal and later.
+
        :param crawler: crawler to which the spider will be bound
        :type crawler: :class:`~scrapy.crawler.Crawler` instance
 
@@ -142,6 +160,46 @@ scrapy.Spider
        :param kwargs: keyword arguments passed to the :meth:`__init__` method
        :type kwargs: dict
 
+   .. classmethod:: update_settings(settings)
+
+       The ``update_settings()`` method is used to modify the spider's settings
+       and is called during initialization of a spider instance.
+
+       It takes a :class:`~scrapy.settings.Settings` object as a parameter and
+       can add or update the spider's configuration values. This method is a
+       class method, meaning that it is called on the :class:`~scrapy.Spider`
+       class and allows all instances of the spider to share the same
+       configuration.
+
+       While per-spider settings can be set in
+       :attr:`~scrapy.Spider.custom_settings`, using ``update_settings()``
+       allows you to dynamically add, remove or change settings based on other
+       settings, spider attributes or other factors and use setting priorities
+       other than ``'spider'``. Also, it's easy to extend ``update_settings()``
+       in a subclass by overriding it, while doing the same with
+       :attr:`~scrapy.Spider.custom_settings` can be hard.
+
+       For example, suppose a spider needs to modify :setting:`FEEDS`:
+
+       .. code-block:: python
+
+           import scrapy
+
+
+           class MySpider(scrapy.Spider):
+               name = "myspider"
+               custom_feed = {
+                   "/home/user/documents/items.json": {
+                       "format": "json",
+                       "indent": 4,
+                   }
+               }
+
+               @classmethod
+               def update_settings(cls, settings):
+                   super().update_settings(settings)
+                   settings.setdefault("FEEDS", {}).update(cls.custom_feed)
+
    .. method:: start_requests()
 
        This method must return an iterable with the first Requests to crawl for
@@ -154,15 +212,24 @@ scrapy.Spider
 
        If you want to change the Requests used to start scraping a domain, this is
        the method to override. For example, if you need to start by logging in using
-       a POST request, you could do::
+       a POST request, you could do:
+
+       .. code-block:: python
+
+           import scrapy
+
 
            class MySpider(scrapy.Spider):
-               name = 'myspider'
+               name = "myspider"
 
                def start_requests(self):
-                   return [scrapy.FormRequest("http://www.example.com/login",
-                                              formdata={'user': 'john', 'pass': 'secret'},
-                                              callback=self.logged_in)]
+                   return [
+                       scrapy.FormRequest(
+                           "http://www.example.com/login",
+                           formdata={"user": "john", "pass": "secret"},
+                           callback=self.logged_in,
+                       )
+                   ]
 
                def logged_in(self, response):
                    # here you would extract links to follow and return Requests for
@@ -178,9 +245,10 @@ scrapy.Spider
        scraped data and/or more URLs to follow. Other Requests callbacks have
        the same requirements as the :class:`Spider` class.
 
-       This method, as well as any other Request callback, must return an
-       iterable of :class:`~scrapy.http.Request` and/or :ref:`item objects
-       <topics-items>`.
+       This method, as well as any other Request callback, must return a
+       :class:`~scrapy.Request` object, an :ref:`item object <topics-items>`, an
+       iterable of :class:`~scrapy.Request` objects and/or :ref:`item objects
+       <topics-items>`, or ``None``.
 
        :param response: the response to parse
        :type response: :class:`~scrapy.http.Response`
@@ -196,63 +264,72 @@ scrapy.Spider
        Called when the spider closes. This method provides a shortcut to
        signals.connect() for the :signal:`spider_closed` signal.
 
-Let's see an example::
+Let's see an example:
+
+.. code-block:: python
 
     import scrapy
 
 
     class MySpider(scrapy.Spider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
+        name = "example.com"
+        allowed_domains = ["example.com"]
         start_urls = [
-            'http://www.example.com/1.html',
-            'http://www.example.com/2.html',
-            'http://www.example.com/3.html',
+            "http://www.example.com/1.html",
+            "http://www.example.com/2.html",
+            "http://www.example.com/3.html",
         ]
 
         def parse(self, response):
-            self.logger.info('A response from %s just arrived!', response.url)
+            self.logger.info("A response from %s just arrived!", response.url)
 
-Return multiple Requests and items from a single callback::
+Return multiple Requests and items from a single callback:
+
+.. code-block:: python
 
     import scrapy
 
+
     class MySpider(scrapy.Spider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
+        name = "example.com"
+        allowed_domains = ["example.com"]
         start_urls = [
-            'http://www.example.com/1.html',
-            'http://www.example.com/2.html',
-            'http://www.example.com/3.html',
+            "http://www.example.com/1.html",
+            "http://www.example.com/2.html",
+            "http://www.example.com/3.html",
         ]
 
         def parse(self, response):
-            for h3 in response.xpath('//h3').getall():
+            for h3 in response.xpath("//h3").getall():
                 yield {"title": h3}
 
-            for href in response.xpath('//a/@href').getall():
+            for href in response.xpath("//a/@href").getall():
                 yield scrapy.Request(response.urljoin(href), self.parse)
 
 Instead of :attr:`~.start_urls` you can use :meth:`~.start_requests` directly;
-to give data more structure you can use :class:`~scrapy.item.Item` objects::
+to give data more structure you can use :class:`~scrapy.Item` objects:
+
+.. skip: next
+.. code-block:: python
 
     import scrapy
     from myproject.items import MyItem
 
+
     class MySpider(scrapy.Spider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
+        name = "example.com"
+        allowed_domains = ["example.com"]
 
         def start_requests(self):
-            yield scrapy.Request('http://www.example.com/1.html', self.parse)
-            yield scrapy.Request('http://www.example.com/2.html', self.parse)
-            yield scrapy.Request('http://www.example.com/3.html', self.parse)
+            yield scrapy.Request("http://www.example.com/1.html", self.parse)
+            yield scrapy.Request("http://www.example.com/2.html", self.parse)
+            yield scrapy.Request("http://www.example.com/3.html", self.parse)
 
         def parse(self, response):
-            for h3 in response.xpath('//h3').getall():
+            for h3 in response.xpath("//h3").getall():
                 yield MyItem(title=h3)
 
-            for href in response.xpath('//a/@href').getall():
+            for href in response.xpath("//a/@href").getall():
                 yield scrapy.Request(response.urljoin(href), self.parse)
 
 .. _spiderargs:
@@ -270,29 +347,46 @@ Spider arguments are passed through the :command:`crawl` command using the
 
     scrapy crawl myspider -a category=electronics
 
-Spiders can access arguments in their `__init__` methods::
+Spiders can access arguments in their `__init__` methods:
+
+.. code-block:: python
 
     import scrapy
 
+
     class MySpider(scrapy.Spider):
-        name = 'myspider'
+        name = "myspider"
 
         def __init__(self, category=None, *args, **kwargs):
             super(MySpider, self).__init__(*args, **kwargs)
-            self.start_urls = [f'http://www.example.com/categories/{category}']
+            self.start_urls = [f"http://www.example.com/categories/{category}"]
             # ...
 
 The default `__init__` method will take any spider arguments
 and copy them to the spider as attributes.
-The above example can also be written as follows::
+The above example can also be written as follows:
+
+.. code-block:: python
 
     import scrapy
 
+
     class MySpider(scrapy.Spider):
-        name = 'myspider'
+        name = "myspider"
 
         def start_requests(self):
-            yield scrapy.Request(f'http://www.example.com/categories/{self.category}')
+            yield scrapy.Request(f"http://www.example.com/categories/{self.category}")
+
+If you are :ref:`running Scrapy from a script <run-from-script>`, you can 
+specify spider arguments when calling 
+:class:`CrawlerProcess.crawl <scrapy.crawler.CrawlerProcess.crawl>` or
+:class:`CrawlerRunner.crawl <scrapy.crawler.CrawlerRunner.crawl>`:
+
+.. skip: next
+.. code-block:: python
+
+    process = CrawlerProcess()
+    process.crawl(MySpider, category="electronics")
 
 Keep in mind that spider arguments are only strings.
 The spider will not do any parsing on its own.
@@ -325,10 +419,13 @@ common scraping cases, like following all links on a site based on certain
 rules, crawling from `Sitemaps`_, or parsing an XML/CSV feed.
 
 For the examples used in the following spiders, we'll assume you have a project
-with a ``TestItem`` declared in a ``myproject.items`` module::
+with a ``TestItem`` declared in a ``myproject.items`` module:
+
+.. code-block:: python
 
     import scrapy
 
+
     class TestItem(scrapy.Item):
         id = scrapy.Field()
         name = scrapy.Field()
@@ -358,14 +455,14 @@ CrawlSpider
        described below. If multiple rules match the same link, the first one
        will be used, according to the order they're defined in this attribute.
 
-   This spider also exposes an overrideable method:
+   This spider also exposes an overridable method:
 
    .. method:: parse_start_url(response, **kwargs)
 
       This method is called for each response produced for the URLs in
       the spider's ``start_urls`` attribute. It allows to parse
       the initial responses and must return either an
-      :ref:`item object <topics-items>`, a :class:`~scrapy.http.Request`
+      :ref:`item object <topics-items>`, a :class:`~scrapy.Request`
       object, or an iterable containing any of them.
 
 Crawling rules
@@ -375,7 +472,7 @@ Crawling rules
 
    ``link_extractor`` is a :ref:`Link Extractor <topics-link-extractors>` object which
    defines how links will be extracted from each crawled page. Each produced link will
-   be used to generate a :class:`~scrapy.http.Request` object, which will contain the
+   be used to generate a :class:`~scrapy.Request` object, which will contain the
    link's text in its ``meta`` dictionary (under the ``link_text`` key).
    If omitted, a default link extractor created with no arguments will be used,
    resulting in all links being extracted.
@@ -384,9 +481,9 @@ Crawling rules
    object with that name will be used) to be called for each link extracted with
    the specified link extractor. This callback receives a :class:`~scrapy.http.Response`
    as its first argument and must return either a single instance or an iterable of
-   :ref:`item objects <topics-items>` and/or :class:`~scrapy.http.Request` objects
+   :ref:`item objects <topics-items>` and/or :class:`~scrapy.Request` objects
    (or any subclass of them). As mentioned above, the received :class:`~scrapy.http.Response`
-   object will contain the text of the link that produced the :class:`~scrapy.http.Request`
+   object will contain the text of the link that produced the :class:`~scrapy.Request`
    in its ``meta`` dictionary (under the ``link_text`` key)
 
    ``cb_kwargs`` is a dict containing the keyword arguments to be passed to the
@@ -403,7 +500,7 @@ Crawling rules
 
    ``process_request`` is a callable (or a string, in which case a method from
    the spider object with that name will be used) which will be called for every
-   :class:`~scrapy.http.Request` extracted by this rule. This callable should
+   :class:`~scrapy.Request` extracted by this rule. This callable should
    take said request as first argument and the :class:`~scrapy.http.Response`
    from which the request originated as second argument. It must return a
    ``Request`` object or ``None`` (to filter out the request).
@@ -414,10 +511,9 @@ Crawling rules
    It receives a :class:`Twisted Failure <twisted.python.failure.Failure>`
    instance as first parameter.
 
-
-.. warning:: Because of its internal implementation, you must explicitly set
-   callbacks for new requests when writing :class:`CrawlSpider`-based spiders;
-   unexpected behaviour can occur otherwise.
+   .. warning:: Because of its internal implementation, you must explicitly set
+      callbacks for new requests when writing :class:`CrawlSpider`-based spiders;
+      unexpected behaviour can occur otherwise.
 
    .. versionadded:: 2.0
       The *errback* parameter.
@@ -425,45 +521,53 @@ Crawling rules
 CrawlSpider example
 ~~~~~~~~~~~~~~~~~~~
 
-Let's now take a look at an example CrawlSpider with rules::
+Let's now take a look at an example CrawlSpider with rules:
+
+.. code-block:: python
 
     import scrapy
     from scrapy.spiders import CrawlSpider, Rule
     from scrapy.linkextractors import LinkExtractor
 
+
     class MySpider(CrawlSpider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
-        start_urls = ['http://www.example.com']
+        name = "example.com"
+        allowed_domains = ["example.com"]
+        start_urls = ["http://www.example.com"]
 
         rules = (
             # Extract links matching 'category.php' (but not matching 'subsection.php')
             # and follow links from them (since no callback means follow=True by default).
-            Rule(LinkExtractor(allow=('category\.php', ), deny=('subsection\.php', ))),
-
+            Rule(LinkExtractor(allow=(r"category\.php",), deny=(r"subsection\.php",))),
             # Extract links matching 'item.php' and parse them with the spider's method parse_item
-            Rule(LinkExtractor(allow=('item\.php', )), callback='parse_item'),
+            Rule(LinkExtractor(allow=(r"item\.php",)), callback="parse_item"),
         )
 
         def parse_item(self, response):
-            self.logger.info('Hi, this is an item page! %s', response.url)
+            self.logger.info("Hi, this is an item page! %s", response.url)
             item = scrapy.Item()
-            item['id'] = response.xpath('//td[@id="item_id"]/text()').re(r'ID: (\d+)')
-            item['name'] = response.xpath('//td[@id="item_name"]/text()').get()
-            item['description'] = response.xpath('//td[@id="item_description"]/text()').get()
-            item['link_text'] = response.meta['link_text']
+            item["id"] = response.xpath('//td[@id="item_id"]/text()').re(r"ID: (\d+)")
+            item["name"] = response.xpath('//td[@id="item_name"]/text()').get()
+            item["description"] = response.xpath(
+                '//td[@id="item_description"]/text()'
+            ).get()
+            item["link_text"] = response.meta["link_text"]
             url = response.xpath('//td[@id="additional_data"]/@href').get()
-            return response.follow(url, self.parse_additional_page, cb_kwargs=dict(item=item))
+            return response.follow(
+                url, self.parse_additional_page, cb_kwargs=dict(item=item)
+            )
 
         def parse_additional_page(self, response, item):
-            item['additional_data'] = response.xpath('//p[@id="additional_data"]/text()').get()
+            item["additional_data"] = response.xpath(
+                '//p[@id="additional_data"]/text()'
+            ).get()
             return item
 
 
 This spider would start crawling example.com's home page, collecting category
 links, and item links, parsing the latter with the ``parse_item`` method. For
 each item response, some data will be extracted from the HTML using XPath, and
-an :class:`~scrapy.item.Item` will be filled with it.
+an :class:`~scrapy.Item` will be filled with it.
 
 XMLFeedSpider
 -------------
@@ -486,11 +590,11 @@ XMLFeedSpider
 
            - ``'iternodes'`` - a fast iterator based on regular expressions
 
-           - ``'html'`` - an iterator which uses :class:`~scrapy.selector.Selector`.
+           - ``'html'`` - an iterator which uses :class:`~scrapy.Selector`.
              Keep in mind this uses DOM parsing and must load all DOM in memory
              which could be a problem for big feeds
 
-           - ``'xml'`` - an iterator which uses :class:`~scrapy.selector.Selector`.
+           - ``'xml'`` - an iterator which uses :class:`~scrapy.Selector`.
              Keep in mind this uses DOM parsing and must load all DOM in memory
              which could be a problem for big feeds
 
@@ -508,7 +612,7 @@ XMLFeedSpider
         available in that document that will be processed with this spider. The
         ``prefix`` and ``uri`` will be used to automatically register
         namespaces using the
-        :meth:`~scrapy.selector.Selector.register_namespace` method.
+        :meth:`~scrapy.Selector.register_namespace` method.
 
         You can then specify nodes with namespaces in the :attr:`itertag`
         attribute.
@@ -521,7 +625,7 @@ XMLFeedSpider
                 itertag = 'n:url'
                 # ...
 
-    Apart from these new attributes, this spider has the following overrideable
+    Apart from these new attributes, this spider has the following overridable
     methods too:
 
     .. method:: adapt_response(response)
@@ -535,10 +639,10 @@ XMLFeedSpider
 
         This method is called for the nodes matching the provided tag name
         (``itertag``).  Receives the response and an
-        :class:`~scrapy.selector.Selector` for each node.  Overriding this
+        :class:`~scrapy.Selector` for each node.  Overriding this
         method is mandatory. Otherwise, you spider won't work.  This method
         must return an :ref:`item object <topics-items>`, a
-        :class:`~scrapy.http.Request` object, or an iterable containing any of
+        :class:`~scrapy.Request` object, or an iterable containing any of
         them.
 
     .. method:: process_results(response, results)
@@ -549,39 +653,44 @@ XMLFeedSpider
         item IDs. It receives a list of results and the response which originated
         those results. It must return a list of results (items or requests).
 
-
-.. warning:: Because of its internal implementation, you must explicitly set
-   callbacks for new requests when writing :class:`XMLFeedSpider`-based spiders;
-   unexpected behaviour can occur otherwise.
+    .. warning:: Because of its internal implementation, you must explicitly set
+       callbacks for new requests when writing :class:`XMLFeedSpider`-based spiders;
+       unexpected behaviour can occur otherwise.
 
 
 XMLFeedSpider example
 ~~~~~~~~~~~~~~~~~~~~~
 
-These spiders are pretty easy to use, let's have a look at one example::
+These spiders are pretty easy to use, let's have a look at one example:
+
+.. skip: next
+.. code-block:: python
 
     from scrapy.spiders import XMLFeedSpider
     from myproject.items import TestItem
 
+
     class MySpider(XMLFeedSpider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
-        start_urls = ['http://www.example.com/feed.xml']
-        iterator = 'iternodes'  # This is actually unnecessary, since it's the default value
-        itertag = 'item'
+        name = "example.com"
+        allowed_domains = ["example.com"]
+        start_urls = ["http://www.example.com/feed.xml"]
+        iterator = "iternodes"  # This is actually unnecessary, since it's the default value
+        itertag = "item"
 
         def parse_node(self, response, node):
-            self.logger.info('Hi, this is a <%s> node!: %s', self.itertag, ''.join(node.getall()))
+            self.logger.info(
+                "Hi, this is a <%s> node!: %s", self.itertag, "".join(node.getall())
+            )
 
             item = TestItem()
-            item['id'] = node.xpath('@id').get()
-            item['name'] = node.xpath('name').get()
-            item['description'] = node.xpath('description').get()
+            item["id"] = node.xpath("@id").get()
+            item["name"] = node.xpath("name").get()
+            item["description"] = node.xpath("description").get()
             return item
 
 Basically what we did up there was to create a spider that downloads a feed from
 the given ``start_urls``, and then iterates through each of its ``item`` tags,
-prints them out, and stores some random data in an :class:`~scrapy.item.Item`.
+prints them out, and stores some random data in an :class:`~scrapy.Item`.
 
 CSVFeedSpider
 -------------
@@ -617,26 +726,30 @@ CSVFeedSpider example
 ~~~~~~~~~~~~~~~~~~~~~
 
 Let's see an example similar to the previous one, but using a
-:class:`CSVFeedSpider`::
+:class:`CSVFeedSpider`:
+
+.. skip: next
+.. code-block:: python
 
     from scrapy.spiders import CSVFeedSpider
     from myproject.items import TestItem
 
+
     class MySpider(CSVFeedSpider):
-        name = 'example.com'
-        allowed_domains = ['example.com']
-        start_urls = ['http://www.example.com/feed.csv']
-        delimiter = ';'
+        name = "example.com"
+        allowed_domains = ["example.com"]
+        start_urls = ["http://www.example.com/feed.csv"]
+        delimiter = ";"
         quotechar = "'"
-        headers = ['id', 'name', 'description']
+        headers = ["id", "name", "description"]
 
         def parse_row(self, response, row):
-            self.logger.info('Hi, this is a row!: %r', row)
+            self.logger.info("Hi, this is a row!: %r", row)
 
             item = TestItem()
-            item['id'] = row['id']
-            item['name'] = row['name']
-            item['description'] = row['description']
+            item["id"] = row["id"]
+            item["name"] = row["name"]
+            item["description"] = row["description"]
             return item
 
 
@@ -718,19 +831,22 @@ SitemapSpider
                 <lastmod>2005-01-01</lastmod>
             </url>
 
-        We can define a ``sitemap_filter`` function to filter ``entries`` by date::
+        We can define a ``sitemap_filter`` function to filter ``entries`` by date:
+
+        .. code-block:: python
 
             from datetime import datetime
             from scrapy.spiders import SitemapSpider
 
+
             class FilteredSitemapSpider(SitemapSpider):
-                name = 'filtered_sitemap_spider'
-                allowed_domains = ['example.com']
-                sitemap_urls = ['http://example.com/sitemap.xml']
+                name = "filtered_sitemap_spider"
+                allowed_domains = ["example.com"]
+                sitemap_urls = ["http://example.com/sitemap.xml"]
 
                 def sitemap_filter(self, entries):
                     for entry in entries:
-                        date_time = datetime.strptime(entry['lastmod'], '%Y-%m-%d')
+                        date_time = datetime.strptime(entry["lastmod"], "%Y-%m-%d")
                         if date_time.year >= 2005:
                             yield entry
 
@@ -755,60 +871,72 @@ SitemapSpider examples
 ~~~~~~~~~~~~~~~~~~~~~~
 
 Simplest example: process all urls discovered through sitemaps using the
-``parse`` callback::
+``parse`` callback:
+
+.. code-block:: python
 
     from scrapy.spiders import SitemapSpider
 
+
     class MySpider(SitemapSpider):
-        sitemap_urls = ['http://www.example.com/sitemap.xml']
+        sitemap_urls = ["http://www.example.com/sitemap.xml"]
 
         def parse(self, response):
-            pass # ... scrape item here ...
+            pass  # ... scrape item here ...
 
 Process some urls with certain callback and other urls with a different
-callback::
+callback:
+
+.. code-block:: python
 
     from scrapy.spiders import SitemapSpider
 
+
     class MySpider(SitemapSpider):
-        sitemap_urls = ['http://www.example.com/sitemap.xml']
+        sitemap_urls = ["http://www.example.com/sitemap.xml"]
         sitemap_rules = [
-            ('/product/', 'parse_product'),
-            ('/category/', 'parse_category'),
+            ("/product/", "parse_product"),
+            ("/category/", "parse_category"),
         ]
 
         def parse_product(self, response):
-            pass # ... scrape product ...
+            pass  # ... scrape product ...
 
         def parse_category(self, response):
-            pass # ... scrape category ...
+            pass  # ... scrape category ...
 
 Follow sitemaps defined in the `robots.txt`_ file and only follow sitemaps
-whose url contains ``/sitemap_shop``::
+whose url contains ``/sitemap_shop``:
+
+.. code-block:: python
 
     from scrapy.spiders import SitemapSpider
 
+
     class MySpider(SitemapSpider):
-        sitemap_urls = ['http://www.example.com/robots.txt']
+        sitemap_urls = ["http://www.example.com/robots.txt"]
         sitemap_rules = [
-            ('/shop/', 'parse_shop'),
+            ("/shop/", "parse_shop"),
         ]
-        sitemap_follow = ['/sitemap_shops']
+        sitemap_follow = ["/sitemap_shops"]
 
         def parse_shop(self, response):
-            pass # ... scrape shop here ...
+            pass  # ... scrape shop here ...
 
-Combine SitemapSpider with other sources of urls::
+Combine SitemapSpider with other sources of urls:
+
+.. code-block:: python
 
     from scrapy.spiders import SitemapSpider
 
+
     class MySpider(SitemapSpider):
-        sitemap_urls = ['http://www.example.com/robots.txt']
+        sitemap_urls = ["http://www.example.com/robots.txt"]
         sitemap_rules = [
-            ('/shop/', 'parse_shop'),
+            ("/shop/", "parse_shop"),
         ]
 
-        other_urls = ['http://www.example.com/about']
+        other_urls = ["http://www.example.com/about"]
 
         def start_requests(self):
             requests = list(super(MySpider, self).start_requests())
@@ -816,10 +944,10 @@ Combine SitemapSpider with other sources of urls::
             return requests
 
         def parse_shop(self, response):
-            pass # ... scrape shop here ...
+            pass  # ... scrape shop here ...
 
         def parse_other(self, response):
-            pass # ... scrape other here ...
+            pass  # ... scrape other here ...
 
 .. _Sitemaps: https://www.sitemaps.org/index.html
 .. _Sitemap index files: https://www.sitemaps.org/protocol.html#index

docs/topics/stats.rst

@@ -30,10 +30,11 @@ Common Stats Collector uses
 ===========================
 
 Access the stats collector through the :attr:`~scrapy.crawler.Crawler.stats`
-attribute. Here is an example of an extension that access stats::
+attribute. Here is an example of an extension that access stats:
+
+.. code-block:: python
 
     class ExtensionThatAccessStats:
-
         def __init__(self, stats):
             self.stats = stats
 
@@ -41,31 +42,43 @@ attribute. Here is an example of an extension that access stats::
         def from_crawler(cls, crawler):
             return cls(crawler.stats)
 
-Set stat value::
+Set stat value:
 
-    stats.set_value('hostname', socket.gethostname())
+.. code-block:: python
 
-Increment stat value::
+    stats.set_value("hostname", socket.gethostname())
 
-    stats.inc_value('custom_count')
+Increment stat value:
 
-Set stat value only if greater than previous::
+.. code-block:: python
 
-    stats.max_value('max_items_scraped', value)
+    stats.inc_value("custom_count")
 
-Set stat value only if lower than previous::
+Set stat value only if greater than previous:
 
-    stats.min_value('min_free_memory_percent', value)
+.. code-block:: python
+
+    stats.max_value("max_items_scraped", value)
+
+Set stat value only if lower than previous:
+
+.. code-block:: python
+
+    stats.min_value("min_free_memory_percent", value)
 
 Get stat value:
 
->>> stats.get_value('custom_count')
-1
+.. code-block:: pycon
+
+    >>> stats.get_value("custom_count")
+    1
 
 Get all stats:
 
->>> stats.get_stats()
-{'custom_count': 1, 'start_time': datetime.datetime(2009, 7, 14, 21, 47, 28, 977139)}
+.. code-block:: pycon
+
+    >>> stats.get_stats()
+    {'custom_count': 1, 'start_time': datetime.datetime(2009, 7, 14, 21, 47, 28, 977139)}
 
 Available Stats Collectors
 ==========================

docs/topics/telnetconsole.rst

@@ -110,11 +110,10 @@ using the telnet console::
     Execution engine status
 
     time()-engine.start_time                        : 8.62972998619
-    engine.has_capacity()                           : False
     len(engine.downloader.active)                   : 16
     engine.scraper.is_idle()                        : False
     engine.spider.name                              : followall
-    engine.spider_is_idle(engine.spider)            : False
+    engine.spider_is_idle()                         : False
     engine.slot.closing                             : False
     len(engine.slot.inprogress)                     : 16
     len(engine.slot.scheduler.dqs or [])            : 0

docs/topics/webservice.rst

@@ -1,11 +0,0 @@
-.. _topics-webservice:
-
-===========
-Web Service
-===========
-
-webservice has been moved into a separate project.
-
-It is hosted at:
-
-    https://github.com/scrapy-plugins/scrapy-jsonrpc

docs/utils/linkfix.py

@@ -13,25 +13,26 @@ Author: dufferzafar
 """
 
 import re
+import sys
+from pathlib import Path
 
 
 def main():
-
     # Used for remembering the file (and its contents)
     # so we don't have to open the same file again.
     _filename = None
     _contents = None
 
     # A regex that matches standard linkcheck output lines
-    line_re = re.compile(r'(.*)\:\d+\:\s\[(.*)\]\s(?:(.*)\sto\s(.*)|(.*))')
+    line_re = re.compile(r"(.*)\:\d+\:\s\[(.*)\]\s(?:(.*)\sto\s(.*)|(.*))")
 
     # Read lines from the linkcheck output file
     try:
-        with open("build/linkcheck/output.txt") as out:
+        with Path("build/linkcheck/output.txt").open(encoding="utf-8") as out:
             output_lines = out.readlines()
-    except IOError:
+    except OSError:
         print("linkcheck output not found; please run linkcheck first.")
-        exit(1)
+        sys.exit(1)
 
     # For every line, fix the respective file
     for line in output_lines:
@@ -48,17 +49,14 @@ def main():
             else:
                 # If this is a new file
                 if newfilename != _filename:
-
                     # Update the previous file
                     if _filename:
-                        with open(_filename, "w") as _file:
-                            _file.write(_contents)
+                        Path(_filename).write_text(_contents, encoding="utf-8")
 
                     _filename = newfilename
 
                     # Read the new file to memory
-                    with open(_filename) as _file:
-                        _contents = _file.read()
+                    _contents = Path(_filename).read_text(encoding="utf-8")
 
                 _contents = _contents.replace(match.group(3), match.group(4))
         else:
@@ -66,5 +64,5 @@ def main():
             print("Not Understood: " + line)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()

docs/versioning.rst

@@ -13,7 +13,7 @@ There are 3 numbers in a Scrapy version: *A.B.C*
   large changes.
 * *B* is the release number. This will include many changes including features
   and things that possibly break backward compatibility, although we strive to
-  keep theses cases at a minimum.
+  keep these cases at a minimum.
 * *C* is the bugfix release number.
 
 Backward-incompatibilities are explicitly mentioned in the :ref:`release notes <news>`,

extras/qps-bench-server.py

@@ -1,13 +1,13 @@
 #!/usr/bin/env python
-from time import time
 from collections import deque
-from twisted.web.server import Site, NOT_DONE_YET
-from twisted.web.resource import Resource
+from time import time
+
 from twisted.internet import reactor
+from twisted.web.resource import Resource
+from twisted.web.server import NOT_DONE_YET, Site
 
 
 class Root(Resource):
-
     def __init__(self):
         Resource.__init__(self)
         self.concurrent = 0
@@ -26,9 +26,9 @@ class Root(Resource):
         delta = now - self.lasttime
 
         # reset stats on high iter-request times caused by client restarts
-        if delta > 3: # seconds
+        if delta > 3:  # seconds
             self._reset_stats()
-            return ''
+            return ""
 
         self.tail.appendleft(delta)
         self.lasttime = now
@@ -37,15 +37,17 @@ class Root(Resource):
         if now - self.lastmark >= 3:
             self.lastmark = now
             qps = len(self.tail) / sum(self.tail)
-            print(f'samplesize={len(self.tail)} concurrent={self.concurrent} qps={qps:0.2f}')
+            print(
+                f"samplesize={len(self.tail)} concurrent={self.concurrent} qps={qps:0.2f}"
+            )
 
-        if 'latency' in request.args:
-            latency = float(request.args['latency'][0])
+        if "latency" in request.args:
+            latency = float(request.args["latency"][0])
             reactor.callLater(latency, self._finish, request)
             return NOT_DONE_YET
 
         self.concurrent -= 1
-        return ''
+        return ""
 
     def _finish(self, request):
         self.concurrent -= 1

extras/qpsclient.py

@@ -1,25 +1,25 @@
 """
-A spider that generate light requests to meassure QPS troughput
+A spider that generate light requests to measure QPS throughput
 
 usage:
 
-    scrapy runspider qpsclient.py --loglevel=INFO --set RANDOMIZE_DOWNLOAD_DELAY=0 --set CONCURRENT_REQUESTS=50 -a qps=10 -a latency=0.3
+    scrapy runspider qpsclient.py --loglevel=INFO --set RANDOMIZE_DOWNLOAD_DELAY=0
+     --set CONCURRENT_REQUESTS=50 -a qps=10 -a latency=0.3
 
 """
 
-from scrapy.spiders import Spider
 from scrapy.http import Request
+from scrapy.spiders import Spider
 
 
 class QPSSpider(Spider):
-
-    name = 'qps'
-    benchurl = 'http://localhost:8880/'
+    name = "qps"
+    benchurl = "http://localhost:8880/"
 
     # Max concurrency is limited by global CONCURRENT_REQUESTS setting
     max_concurrent_requests = 8
     # Requests per second goal
-    qps = None # same as: 1 / download_delay
+    qps = None  # same as: 1 / download_delay
     download_delay = None
     # time in seconds to delay server responses
     latency = None
@@ -37,11 +37,11 @@ class QPSSpider(Spider):
     def start_requests(self):
         url = self.benchurl
         if self.latency is not None:
-            url += f'?latency={self.latency}'
+            url += f"?latency={self.latency}"
 
         slots = int(self.slots)
         if slots > 1:
-            urls = [url.replace('localhost', f'127.0.0.{x + 1}') for x in range(slots)]
+            urls = [url.replace("localhost", f"127.0.0.{x + 1}") for x in range(slots)]
         else:
             urls = [url]
 

pylintrc

@@ -6,34 +6,30 @@ jobs=1  # >1 hides results
 disable=abstract-method,
         anomalous-backslash-in-string,
         arguments-differ,
+        arguments-renamed,
         attribute-defined-outside-init,
         bad-classmethod-argument,
-        bad-continuation,
-        bad-indentation,
         bad-mcs-classmethod-argument,
-        bad-super-call,
-        bad-whitespace,
         bare-except,
-        blacklisted-name,
         broad-except,
+        broad-exception-raised,
         c-extension-no-member,
         catching-non-exception,
         cell-var-from-loop,
         comparison-with-callable,
-        consider-iterating-dictionary,
+        consider-using-dict-items,
         consider-using-in,
-        consider-using-set-comprehension,
-        consider-using-sys-exit,
+        consider-using-with,
         cyclic-import,
         dangerous-default-value,
-        deprecated-method,
-        deprecated-module,
+        disallowed-name,
         duplicate-code,  # https://github.com/PyCQA/pylint/issues/214
         eval-used,
         expression-not-assigned,
         fixme,
         function-redefined,
         global-statement,
+        implicit-str-concat,
         import-error,
         import-outside-toplevel,
         import-self,
@@ -45,26 +41,20 @@ disable=abstract-method,
         keyword-arg-before-vararg,
         line-too-long,
         logging-format-interpolation,
+        logging-fstring-interpolation,
         logging-not-lazy,
         lost-exception,
         method-hidden,
-        misplaced-comparison-constant,
         missing-docstring,
-        missing-final-newline,
-        multiple-imports,
-        multiple-statements,
-        no-else-continue,
         no-else-raise,
         no-else-return,
-        no-init,
         no-member,
         no-method-argument,
         no-name-in-module,
         no-self-argument,
-        no-self-use,
         no-value-for-parameter,
-        not-an-iterable,
         not-callable,
+        pointless-exception-statement,
         pointless-statement,
         pointless-string-statement,
         protected-access,
@@ -74,10 +64,7 @@ disable=abstract-method,
         redefined-outer-name,
         reimported,
         signature-differs,
-        singleton-comparison,
         super-init-not-called,
-        super-with-arguments,
-        superfluous-parens,
         too-few-public-methods,
         too-many-ancestors,
         too-many-arguments,
@@ -89,27 +76,24 @@ disable=abstract-method,
         too-many-locals,
         too-many-public-methods,
         too-many-return-statements,
-        trailing-newlines,
-        trailing-whitespace,
         unbalanced-tuple-unpacking,
         undefined-variable,
         undefined-loop-variable,
         unexpected-special-method-signature,
-        ungrouped-imports,
-        unidiomatic-typecheck,
         unnecessary-comprehension,
-        unnecessary-lambda,
+        unnecessary-dunder-call,
         unnecessary-pass,
         unreachable,
         unsubscriptable-object,
         unused-argument,
         unused-import,
+        unused-private-member,
         unused-variable,
         unused-wildcard-import,
+        use-dict-literal,
         used-before-assignment,
         useless-object-inheritance,  # Required for Python 2 support
         useless-return,
         useless-super-delegation,
         wildcard-import,
-        wrong-import-order,
         wrong-import-position

pytest.ini

@@ -1,10 +1,10 @@
 [pytest]
+xfail_strict = true
 usefixtures = chdir
 python_files=test_*.py __init__.py
 python_classes=
 addopts =
     --assert=plain
-    --doctest-modules
     --ignore=docs/_ext
     --ignore=docs/conf.py
     --ignore=docs/news.rst
@@ -17,27 +17,12 @@ addopts =
     --ignore=docs/topics/stats.rst
     --ignore=docs/topics/telnetconsole.rst
     --ignore=docs/utils
-twisted = 1
 markers =
     only_asyncio: marks tests as only enabled when --reactor=asyncio is passed
-flake8-max-line-length = 119
-flake8-ignore =
-    W503
-
-    # Exclude files that are meant to provide top-level imports
-    # E402: Module level import not at top of file
-    # F401: Module imported but unused
-    scrapy/__init__.py E402
-    scrapy/core/downloader/handlers/http.py F401
-    scrapy/http/__init__.py F401
-    scrapy/linkextractors/__init__.py E402 F401
-    scrapy/selector/__init__.py F401
-    scrapy/spiders/__init__.py E402 F401
-
-    # Issues pending a review:
-    scrapy/utils/http.py F403
-    scrapy/utils/markup.py F403
-    scrapy/utils/multipart.py F403
-    scrapy/utils/url.py F403 F405
-    tests/test_loader.py E741
-    
+    only_not_asyncio: marks tests as only enabled when --reactor=asyncio is not passed
+    requires_uvloop: marks tests as only enabled when uvloop is known to be working
+filterwarnings =
+    ignore:scrapy.downloadermiddlewares.decompression is deprecated
+    ignore:Module scrapy.utils.reqser is deprecated
+    ignore:typing.re is deprecated
+    ignore:typing.io is deprecated

scrapy/VERSION

@@ -1 +1 @@
-2.3.0
+2.11.0

scrapy/__init__.py

@@ -9,32 +9,38 @@ import warnings
 from twisted import version as _txv
 
 # Declare top-level shortcuts
-from scrapy.spiders import Spider
-from scrapy.http import Request, FormRequest
+from scrapy.http import FormRequest, Request
+from scrapy.item import Field, Item
 from scrapy.selector import Selector
-from scrapy.item import Item, Field
-
+from scrapy.spiders import Spider
 
 __all__ = [
-    '__version__', 'version_info', 'twisted_version', 'Spider',
-    'Request', 'FormRequest', 'Selector', 'Item', 'Field',
+    "__version__",
+    "version_info",
+    "twisted_version",
+    "Spider",
+    "Request",
+    "FormRequest",
+    "Selector",
+    "Item",
+    "Field",
 ]
 
 
 # Scrapy and Twisted versions
-__version__ = pkgutil.get_data(__package__, 'VERSION').decode('ascii').strip()
-version_info = tuple(int(v) if v.isdigit() else v for v in __version__.split('.'))
+__version__ = (pkgutil.get_data(__package__, "VERSION") or b"").decode("ascii").strip()
+version_info = tuple(int(v) if v.isdigit() else v for v in __version__.split("."))
 twisted_version = (_txv.major, _txv.minor, _txv.micro)
 
 
 # Check minimum required Python version
-if sys.version_info < (3, 6):
-    print("Scrapy %s requires Python 3.6+" % __version__)
+if sys.version_info < (3, 8):
+    print(f"Scrapy {__version__} requires Python 3.8+")
     sys.exit(1)
 
 
 # Ignore noisy twisted deprecation warnings
-warnings.filterwarnings('ignore', category=DeprecationWarning, module='twisted')
+warnings.filterwarnings("ignore", category=DeprecationWarning, module="twisted")
 
 
 del pkgutil

scrapy/__main__.py

@@ -1,4 +1,4 @@
 from scrapy.cmdline import execute
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     execute()

scrapy/addons.py

@@ -0,0 +1,51 @@
+import logging
+from typing import TYPE_CHECKING, Any, List
+
+from scrapy.exceptions import NotConfigured
+from scrapy.settings import Settings
+from scrapy.utils.conf import build_component_list
+from scrapy.utils.misc import build_from_crawler, load_object
+
+if TYPE_CHECKING:
+    from scrapy.crawler import Crawler
+
+logger = logging.getLogger(__name__)
+
+
+class AddonManager:
+    """This class facilitates loading and storing :ref:`topics-addons`."""
+
+    def __init__(self, crawler: "Crawler") -> None:
+        self.crawler: "Crawler" = crawler
+        self.addons: List[Any] = []
+
+    def load_settings(self, settings: Settings) -> None:
+        """Load add-ons and configurations from a settings object and apply them.
+
+        This will load the add-on for every add-on path in the
+        ``ADDONS`` setting and execute their ``update_settings`` methods.
+
+        :param settings: The :class:`~scrapy.settings.Settings` object from \
+            which to read the add-on configuration
+        :type settings: :class:`~scrapy.settings.Settings`
+        """
+        for clspath in build_component_list(settings["ADDONS"]):
+            try:
+                addoncls = load_object(clspath)
+                addon = build_from_crawler(addoncls, self.crawler)
+                addon.update_settings(settings)
+                self.addons.append(addon)
+            except NotConfigured as e:
+                if e.args:
+                    logger.warning(
+                        "Disabled %(clspath)s: %(eargs)s",
+                        {"clspath": clspath, "eargs": e.args[0]},
+                        extra={"crawler": self.crawler},
+                    )
+        logger.info(
+            "Enabled addons:\n%(addons)s",
+            {
+                "addons": self.addons,
+            },
+            extra={"crawler": self.crawler},
+        )

scrapy/cmdline.py

@@ -1,21 +1,30 @@
-import sys
-import os
-import optparse
+import argparse
 import cProfile
 import inspect
-import pkg_resources
+import os
+import sys
+from importlib.metadata import entry_points
 
 import scrapy
+from scrapy.commands import BaseRunSpiderCommand, ScrapyCommand, ScrapyHelpFormatter
 from scrapy.crawler import CrawlerProcess
-from scrapy.commands import ScrapyCommand
 from scrapy.exceptions import UsageError
 from scrapy.utils.misc import walk_modules
-from scrapy.utils.project import inside_project, get_project_settings
+from scrapy.utils.project import get_project_settings, inside_project
 from scrapy.utils.python import garbage_collect
 
 
+class ScrapyArgumentParser(argparse.ArgumentParser):
+    def _parse_optional(self, arg_string):
+        # if starts with -: it means that is a parameter not a argument
+        if arg_string[:2] == "-:":
+            return None
+
+        return super()._parse_optional(arg_string)
+
+
 def _iter_command_classes(module_name):
-    # TODO: add `name` attribute to commands and and merge this function with
+    # TODO: add `name` attribute to commands and merge this function with
     # scrapy.utils.spider.iter_spider_classes
     for module in walk_modules(module_name):
         for obj in vars(module).values():
@@ -23,7 +32,7 @@ def _iter_command_classes(module_name):
                 inspect.isclass(obj)
                 and issubclass(obj, ScrapyCommand)
                 and obj.__module__ == module.__name__
-                and not obj == ScrapyCommand
+                and obj not in (ScrapyCommand, BaseRunSpiderCommand)
             ):
                 yield obj
 
@@ -32,14 +41,18 @@ def _get_commands_from_module(module, inproject):
     d = {}
     for cmd in _iter_command_classes(module):
         if inproject or not cmd.requires_project:
-            cmdname = cmd.__module__.split('.')[-1]
+            cmdname = cmd.__module__.split(".")[-1]
             d[cmdname] = cmd()
     return d
 
 
-def _get_commands_from_entry_points(inproject, group='scrapy.commands'):
+def _get_commands_from_entry_points(inproject, group="scrapy.commands"):
     cmds = {}
-    for entry_point in pkg_resources.iter_entry_points(group):
+    if sys.version_info >= (3, 10):
+        eps = entry_points(group=group)
+    else:
+        eps = entry_points().get(group, ())
+    for entry_point in eps:
         obj = entry_point.load()
         if inspect.isclass(obj):
             cmds[entry_point.name] = obj()
@@ -49,9 +62,9 @@ def _get_commands_from_entry_points(inproject, group='scrapy.commands'):
 
 
 def _get_commands_dict(settings, inproject):
-    cmds = _get_commands_from_module('scrapy.commands', inproject)
+    cmds = _get_commands_from_module("scrapy.commands", inproject)
     cmds.update(_get_commands_from_entry_points(inproject))
-    cmds_module = settings['COMMANDS_MODULE']
+    cmds_module = settings["COMMANDS_MODULE"]
     if cmds_module:
         cmds.update(_get_commands_from_module(cmds_module, inproject))
     return cmds
@@ -60,7 +73,7 @@ def _get_commands_dict(settings, inproject):
 def _pop_command_name(argv):
     i = 0
     for arg in argv[1:]:
-        if not arg.startswith('-'):
+        if not arg.startswith("-"):
             del argv[i]
             return arg
         i += 1
@@ -69,7 +82,8 @@ def _pop_command_name(argv):
 def _print_header(settings, inproject):
     version = scrapy.__version__
     if inproject:
-        print(f"Scrapy {version} - project: {settings['BOT_NAME']}\n")
+        print(f"Scrapy {version} - active project: {settings['BOT_NAME']}\n")
+
     else:
         print(f"Scrapy {version} - no active project\n")
 
@@ -114,17 +128,15 @@ def execute(argv=None, settings=None):
         settings = get_project_settings()
         # set EDITOR from environment if available
         try:
-            editor = os.environ['EDITOR']
+            editor = os.environ["EDITOR"]
         except KeyError:
             pass
         else:
-            settings['EDITOR'] = editor
+            settings["EDITOR"] = editor
 
     inproject = inside_project()
     cmds = _get_commands_dict(settings, inproject)
     cmdname = _pop_command_name(argv)
-    parser = optparse.OptionParser(formatter=optparse.TitledHelpFormatter(),
-                                   conflict_handler='resolve')
     if not cmdname:
         _print_commands(settings, inproject)
         sys.exit(0)
@@ -133,12 +145,16 @@ def execute(argv=None, settings=None):
         sys.exit(2)
 
     cmd = cmds[cmdname]
-    parser.usage = f"scrapy {cmdname} {cmd.syntax()}"
-    parser.description = cmd.long_desc()
-    settings.setdict(cmd.default_settings, priority='command')
+    parser = ScrapyArgumentParser(
+        formatter_class=ScrapyHelpFormatter,
+        usage=f"scrapy {cmdname} {cmd.syntax()}",
+        conflict_handler="resolve",
+        description=cmd.long_desc(),
+    )
+    settings.setdict(cmd.default_settings, priority="command")
     cmd.settings = settings
     cmd.add_options(parser)
-    opts, args = parser.parse_args(args=argv[1:])
+    opts, args = parser.parse_known_args(args=argv[1:])
     _run_print_help(parser, cmd.process_options, args, opts)
 
     cmd.crawler_process = CrawlerProcess(settings)
@@ -158,12 +174,12 @@ def _run_command_profiled(cmd, args, opts):
         sys.stderr.write(f"scrapy: writing cProfile stats to {opts.profile!r}\n")
     loc = locals()
     p = cProfile.Profile()
-    p.runctx('cmd.run(args, opts)', globals(), loc)
+    p.runctx("cmd.run(args, opts)", globals(), loc)
     if opts.profile:
         p.dump_stats(opts.profile)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     try:
         execute()
     finally:

scrapy/commands/__init__.py

@@ -1,29 +1,32 @@
 """
 Base class for Scrapy commands
 """
+import argparse
 import os
-from optparse import OptionGroup
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
 from twisted.python import failure
 
-from scrapy.utils.conf import arglist_to_dict, feed_process_params_from_cli
+from scrapy.crawler import CrawlerProcess
 from scrapy.exceptions import UsageError
+from scrapy.utils.conf import arglist_to_dict, feed_process_params_from_cli
 
 
 class ScrapyCommand:
-
     requires_project = False
-    crawler_process = None
+    crawler_process: Optional[CrawlerProcess] = None
 
     # default settings to be used for this command instead of global defaults
-    default_settings = {}
+    default_settings: Dict[str, Any] = {}
 
     exitcode = 0
 
-    def __init__(self):
-        self.settings = None  # set in scrapy.cmdline
+    def __init__(self) -> None:
+        self.settings: Any = None  # set in scrapy.cmdline
 
     def set_crawler(self, crawler):
-        if hasattr(self, '_crawler'):
+        if hasattr(self, "_crawler"):
             raise RuntimeError("crawler already set")
         self._crawler = crawler
 
@@ -41,14 +44,14 @@ class ScrapyCommand:
 
     def long_desc(self):
         """A long description of the command. Return short description when not
-        available. It cannot contain newlines, since contents will be formatted
+        available. It cannot contain newlines since contents will be formatted
         by optparser which removes newlines and wraps text.
         """
         return self.short_desc()
 
     def help(self):
         """An extensive help for the command. It will be shown when using the
-        "help" command. It can contain newlines, since no post-formatting will
+        "help" command. It can contain newlines since no post-formatting will
         be applied to its contents.
         """
         return self.long_desc()
@@ -57,49 +60,63 @@ class ScrapyCommand:
         """
         Populate option parse with options available for this command
         """
-        group = OptionGroup(parser, "Global Options")
-        group.add_option("--logfile", metavar="FILE",
-                         help="log file. if omitted stderr will be used")
-        group.add_option("-L", "--loglevel", metavar="LEVEL", default=None,
-                         help=f"log level (default: {self.settings['LOG_LEVEL']})")
-        group.add_option("--nolog", action="store_true",
-                         help="disable logging completely")
-        group.add_option("--profile", metavar="FILE", default=None,
-                         help="write python cProfile stats to FILE")
-        group.add_option("--pidfile", metavar="FILE",
-                         help="write process ID to FILE")
-        group.add_option("-s", "--set", action="append", default=[], metavar="NAME=VALUE",
-                         help="set/override setting (may be repeated)")
-        group.add_option("--pdb", action="store_true", help="enable pdb on failure")
-
-        parser.add_option_group(group)
+        group = parser.add_argument_group(title="Global Options")
+        group.add_argument(
+            "--logfile", metavar="FILE", help="log file. if omitted stderr will be used"
+        )
+        group.add_argument(
+            "-L",
+            "--loglevel",
+            metavar="LEVEL",
+            default=None,
+            help=f"log level (default: {self.settings['LOG_LEVEL']})",
+        )
+        group.add_argument(
+            "--nolog", action="store_true", help="disable logging completely"
+        )
+        group.add_argument(
+            "--profile",
+            metavar="FILE",
+            default=None,
+            help="write python cProfile stats to FILE",
+        )
+        group.add_argument("--pidfile", metavar="FILE", help="write process ID to FILE")
+        group.add_argument(
+            "-s",
+            "--set",
+            action="append",
+            default=[],
+            metavar="NAME=VALUE",
+            help="set/override setting (may be repeated)",
+        )
+        group.add_argument("--pdb", action="store_true", help="enable pdb on failure")
 
     def process_options(self, args, opts):
         try:
-            self.settings.setdict(arglist_to_dict(opts.set),
-                                  priority='cmdline')
+            self.settings.setdict(arglist_to_dict(opts.set), priority="cmdline")
         except ValueError:
             raise UsageError("Invalid -s value, use -s NAME=VALUE", print_help=False)
 
         if opts.logfile:
-            self.settings.set('LOG_ENABLED', True, priority='cmdline')
-            self.settings.set('LOG_FILE', opts.logfile, priority='cmdline')
+            self.settings.set("LOG_ENABLED", True, priority="cmdline")
+            self.settings.set("LOG_FILE", opts.logfile, priority="cmdline")
 
         if opts.loglevel:
-            self.settings.set('LOG_ENABLED', True, priority='cmdline')
-            self.settings.set('LOG_LEVEL', opts.loglevel, priority='cmdline')
+            self.settings.set("LOG_ENABLED", True, priority="cmdline")
+            self.settings.set("LOG_LEVEL", opts.loglevel, priority="cmdline")
 
         if opts.nolog:
-            self.settings.set('LOG_ENABLED', False, priority='cmdline')
+            self.settings.set("LOG_ENABLED", False, priority="cmdline")
 
         if opts.pidfile:
-            with open(opts.pidfile, "w") as f:
-                f.write(str(os.getpid()) + os.linesep)
+            Path(opts.pidfile).write_text(
+                str(os.getpid()) + os.linesep, encoding="utf-8"
+            )
 
         if opts.pdb:
             failure.startDebugMode()
 
-    def run(self, args, opts):
+    def run(self, args: List[str], opts: argparse.Namespace) -> None:
         """
         Entry point for running commands
         """
@@ -110,16 +127,39 @@ class BaseRunSpiderCommand(ScrapyCommand):
     """
     Common class used to share functionality between the crawl, parse and runspider commands
     """
+
     def add_options(self, parser):
         ScrapyCommand.add_options(self, parser)
-        parser.add_option("-a", dest="spargs", action="append", default=[], metavar="NAME=VALUE",
-                          help="set spider argument (may be repeated)")
-        parser.add_option("-o", "--output", metavar="FILE", action="append",
-                          help="append scraped items to the end of FILE (use - for stdout)")
-        parser.add_option("-O", "--overwrite-output", metavar="FILE", action="append",
-                          help="dump scraped items into FILE, overwriting any existing file")
-        parser.add_option("-t", "--output-format", metavar="FORMAT",
-                          help="format to use for dumping items")
+        parser.add_argument(
+            "-a",
+            dest="spargs",
+            action="append",
+            default=[],
+            metavar="NAME=VALUE",
+            help="set spider argument (may be repeated)",
+        )
+        parser.add_argument(
+            "-o",
+            "--output",
+            metavar="FILE",
+            action="append",
+            help="append scraped items to the end of FILE (use - for stdout),"
+            " to define format set a colon at the end of the output URI (i.e. -o FILE:FORMAT)",
+        )
+        parser.add_argument(
+            "-O",
+            "--overwrite-output",
+            metavar="FILE",
+            action="append",
+            help="dump scraped items into FILE, overwriting any existing file,"
+            " to define format set a colon at the end of the output URI (i.e. -O FILE:FORMAT)",
+        )
+        parser.add_argument(
+            "-t",
+            "--output-format",
+            metavar="FORMAT",
+            help="format to use for dumping items",
+        )
 
     def process_options(self, args, opts):
         ScrapyCommand.process_options(self, args, opts)
@@ -134,4 +174,38 @@ class BaseRunSpiderCommand(ScrapyCommand):
                 opts.output_format,
                 opts.overwrite_output,
             )
-            self.settings.set('FEEDS', feeds, priority='cmdline')
+            self.settings.set("FEEDS", feeds, priority="cmdline")
+
+
+class ScrapyHelpFormatter(argparse.HelpFormatter):
+    """
+    Help Formatter for scrapy command line help messages.
+    """
+
+    def __init__(self, prog, indent_increment=2, max_help_position=24, width=None):
+        super().__init__(
+            prog,
+            indent_increment=indent_increment,
+            max_help_position=max_help_position,
+            width=width,
+        )
+
+    def _join_parts(self, part_strings):
+        parts = self.format_part_strings(part_strings)
+        return super()._join_parts(parts)
+
+    def format_part_strings(self, part_strings):
+        """
+        Underline and title case command line help message headers.
+        """
+        if part_strings and part_strings[0].startswith("usage: "):
+            part_strings[0] = "Usage\n=====\n  " + part_strings[0][len("usage: ") :]
+        headings = [
+            i for i in range(len(part_strings)) if part_strings[i].endswith(":\n")
+        ]
+        for index in headings[::-1]:
+            char = "-" if "Global Options" in part_strings[index] else "="
+            part_strings[index] = part_strings[index][:-2].title()
+            underline = "".join(["\n", (char * len(part_strings[index])), "\n"])
+            part_strings.insert(index + 1, underline)
+        return part_strings

scrapy/commands/bench.py

@@ -1,6 +1,6 @@
+import subprocess
 import sys
 import time
-import subprocess
 from urllib.parse import urlencode
 
 import scrapy
@@ -9,11 +9,10 @@ from scrapy.linkextractors import LinkExtractor
 
 
 class Command(ScrapyCommand):
-
     default_settings = {
-        'LOG_LEVEL': 'INFO',
-        'LOGSTATS_INTERVAL': 1,
-        'CLOSESPIDER_TIMEOUT': 10,
+        "LOG_LEVEL": "INFO",
+        "LOGSTATS_INTERVAL": 1,
+        "CLOSESPIDER_TIMEOUT": 10,
     }
 
     def short_desc(self):
@@ -26,12 +25,11 @@ class Command(ScrapyCommand):
 
 
 class _BenchServer:
-
     def __enter__(self):
         from scrapy.utils.test import get_testenv
-        pargs = [sys.executable, '-u', '-m', 'scrapy.utils.benchserver']
-        self.proc = subprocess.Popen(pargs, stdout=subprocess.PIPE,
-                                     env=get_testenv())
+
+        pargs = [sys.executable, "-u", "-m", "scrapy.utils.benchserver"]
+        self.proc = subprocess.Popen(pargs, stdout=subprocess.PIPE, env=get_testenv())
         self.proc.stdout.readline()
 
     def __exit__(self, exc_type, exc_value, traceback):
@@ -42,15 +40,16 @@ class _BenchServer:
 
 class _BenchSpider(scrapy.Spider):
     """A spider that follows all links"""
-    name = 'follow'
+
+    name = "follow"
     total = 10000
     show = 20
-    baseurl = 'http://localhost:8998'
+    baseurl = "http://localhost:8998"
     link_extractor = LinkExtractor()
 
     def start_requests(self):
-        qargs = {'total': self.total, 'show': self.show}
-        url = f'{self.baseurl}?{urlencode(qargs, doseq=1)}'
+        qargs = {"total": self.total, "show": self.show}
+        url = f"{self.baseurl}?{urlencode(qargs, doseq=True)}"
         return [scrapy.Request(url, dont_filter=True)]
 
     def parse(self, response):

scrapy/commands/check.py

@@ -1,11 +1,12 @@
 import time
 from collections import defaultdict
-from unittest import TextTestRunner, TextTestResult as _TextTestResult
+from unittest import TextTestResult as _TextTestResult
+from unittest import TextTestRunner
 
 from scrapy.commands import ScrapyCommand
 from scrapy.contracts import ContractsManager
-from scrapy.utils.misc import load_object, set_environ
 from scrapy.utils.conf import build_component_list
+from scrapy.utils.misc import load_object, set_environ
 
 
 class TextTestResult(_TextTestResult):
@@ -39,7 +40,7 @@ class TextTestResult(_TextTestResult):
 
 class Command(ScrapyCommand):
     requires_project = True
-    default_settings = {'LOG_ENABLED': False}
+    default_settings = {"LOG_ENABLED": False}
 
     def syntax(self):
         return "[options] <spider>"
@@ -49,14 +50,25 @@ class Command(ScrapyCommand):
 
     def add_options(self, parser):
         ScrapyCommand.add_options(self, parser)
-        parser.add_option("-l", "--list", dest="list", action="store_true",
-                          help="only list contracts, without checking them")
-        parser.add_option("-v", "--verbose", dest="verbose", default=False, action='store_true',
-                          help="print contract tests for all spiders")
+        parser.add_argument(
+            "-l",
+            "--list",
+            dest="list",
+            action="store_true",
+            help="only list contracts, without checking them",
+        )
+        parser.add_argument(
+            "-v",
+            "--verbose",
+            dest="verbose",
+            default=False,
+            action="store_true",
+            help="print contract tests for all spiders",
+        )
 
     def run(self, args, opts):
         # load contracts
-        contracts = build_component_list(self.settings.getwithbase('SPIDER_CONTRACTS'))
+        contracts = build_component_list(self.settings.getwithbase("SPIDER_CONTRACTS"))
         conman = ContractsManager(load_object(c) for c in contracts)
         runner = TextTestRunner(verbosity=2 if opts.verbose else 1)
         result = TextTestResult(runner.stream, runner.descriptions, runner.verbosity)
@@ -66,7 +78,7 @@ class Command(ScrapyCommand):
 
         spider_loader = self.crawler_process.spider_loader
 
-        with set_environ(SCRAPY_CHECK='true'):
+        with set_environ(SCRAPY_CHECK="true"):
             for spidername in args or spider_loader.list():
                 spidercls = spider_loader.load(spidername)
                 spidercls.start_requests = lambda s: conman.from_spider(s, result)
@@ -85,7 +97,7 @@ class Command(ScrapyCommand):
                         continue
                     print(spider)
                     for method in sorted(methods):
-                        print(f'  * {method}')
+                        print(f"  * {method}")
             else:
                 start = time.time()
                 self.crawler_process.start()

scrapy/commands/crawl.py

@@ -3,7 +3,6 @@ from scrapy.exceptions import UsageError
 
 
 class Command(BaseRunSpiderCommand):
-
     requires_project = True
 
     def syntax(self):
@@ -16,18 +15,23 @@ class Command(BaseRunSpiderCommand):
         if len(args) < 1:
             raise UsageError()
         elif len(args) > 1:
-            raise UsageError("running 'scrapy crawl' with more than one spider is no longer supported")
+            raise UsageError(
+                "running 'scrapy crawl' with more than one spider is not supported"
+            )
         spname = args[0]
 
         crawl_defer = self.crawler_process.crawl(spname, **opts.spargs)
 
-        if getattr(crawl_defer, 'result', None) is not None and issubclass(crawl_defer.result.type, Exception):
+        if getattr(crawl_defer, "result", None) is not None and issubclass(
+            crawl_defer.result.type, Exception
+        ):
             self.exitcode = 1
         else:
             self.crawler_process.start()
 
             if (
                 self.crawler_process.bootstrap_failed
-                or hasattr(self.crawler_process, 'has_exception') and self.crawler_process.has_exception
+                or hasattr(self.crawler_process, "has_exception")
+                and self.crawler_process.has_exception
             ):
                 self.exitcode = 1

scrapy/commands/edit.py

@@ -1,14 +1,13 @@
-import sys
 import os
+import sys
 
 from scrapy.commands import ScrapyCommand
 from scrapy.exceptions import UsageError
 
 
 class Command(ScrapyCommand):
-
     requires_project = True
-    default_settings = {'LOG_ENABLED': False}
+    default_settings = {"LOG_ENABLED": False}
 
     def syntax(self):
         return "<spider>"
@@ -17,8 +16,10 @@ class Command(ScrapyCommand):
         return "Edit spider"
 
     def long_desc(self):
-        return ("Edit a spider using the editor defined in the EDITOR environment"
-                " variable or else the EDITOR setting")
+        return (
+            "Edit a spider using the editor defined in the EDITOR environment"
+            " variable or else the EDITOR setting"
+        )
 
     def _err(self, msg):
         sys.stderr.write(msg + os.linesep)
@@ -28,12 +29,12 @@ class Command(ScrapyCommand):
         if len(args) != 1:
             raise UsageError()
 
-        editor = self.settings['EDITOR']
+        editor = self.settings["EDITOR"]
         try:
             spidercls = self.crawler_process.spider_loader.load(args[0])
         except KeyError:
             return self._err(f"Spider not found: {args[0]}")
 
         sfile = sys.modules[spidercls.__module__].__file__
-        sfile = sfile.replace('.pyc', '.py')
+        sfile = sfile.replace(".pyc", ".py")
         self.exitcode = os.system(f'{editor} "{sfile}"')