Merge branch 'master' into addons

.bandit.yml

@@ -0,0 +1,21 @@
+skips:
+- B101
+- B113  # https://github.com/PyCQA/bandit/issues/1010
+- B105
+- B301
+- B303
+- B306
+- B307
+- B311
+- B320
+- B321
+- B324
+- B402  # https://github.com/scrapy/scrapy/issues/4180
+- B403
+- B404
+- B406
+- B410
+- B503
+- B603
+- B605
+exclude_dirs: ['tests']

.bumpversion.cfg

@@ -1,27 +1,7 @@
 [bumpversion]
-current_version = 1.1.0dev1
+current_version = 2.9.0
 commit = True
 tag = True
 tag_name = {new_version}
-parse = ^
-	(?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)
-	(?:(?P<prerel>[abc]|rc|dev)(?P<prerelversion>\d+))?
-serialize = 
-	{major}.{minor}.{patch}{prerel}{prerelversion}
-	{major}.{minor}.{patch}
 
 [bumpversion:file:scrapy/VERSION]
-
-[bumpversion:part:prerel]
-optional_value = gamma
-values = 
-	dev
-	rc
-	gamma
-
-[bumpversion:part:prerelversion]
-values = 
-	1
-	2
-	3
-

.coveragerc

@@ -3,17 +3,4 @@ branch = true
 include = scrapy/*
 omit =
   tests/*
-  scrapy/xlib/*
-  scrapy/conf.py
-  scrapy/stats.py
-  scrapy/project.py
-  scrapy/utils/decorator.py
-  scrapy/statscol.py
-  scrapy/squeue.py
-  scrapy/log.py
-  scrapy/dupefilter.py
-  scrapy/command.py
-  scrapy/linkextractor.py
-  scrapy/spider.py
-  scrapy/contrib/*
-  scrapy/contrib_exp/*
+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

.gitattributes

@@ -0,0 +1 @@
+tests/sample_data/** binary

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,41 @@
+---
+name: Bug report
+about: Report a problem to help us improve
+---
+
+<!--
+
+Thanks for taking an interest in Scrapy!
+
+If you have a question that starts with "How to...", please see the Scrapy Community page: https://scrapy.org/community/.
+The GitHub issue tracker's purpose is to deal with bug reports and feature requests for the project itself.
+
+Keep in mind that by filing an issue, you are expected to comply with Scrapy's Code of Conduct, including treating everyone with respect: https://github.com/scrapy/scrapy/blob/master/CODE_OF_CONDUCT.md
+
+The following is a suggested template to structure your issue, you can find more guidelines at https://doc.scrapy.org/en/latest/contributing.html#reporting-bugs
+
+-->
+
+### Description
+
+[Description of the issue]
+
+### Steps to Reproduce
+
+1. [First Step]
+2. [Second Step]
+3. [and so on...]
+
+**Expected behavior:** [What you expect to happen]
+
+**Actual behavior:** [What actually happens]
+
+**Reproduces how often:** [What percentage of the time does it reproduce?]
+
+### Versions
+
+Please paste here the output of executing `scrapy version --verbose` in the command line.
+
+### Additional context
+
+Any additional information, configuration, data or output from commands that might be necessary to reproduce or understand the issue. Please try not to include screenshots of code or the command line, paste the contents as text instead. You can use [GitHub Flavored Markdown](https://help.github.com/en/articles/creating-and-highlighting-code-blocks) to make the text look better.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,33 @@
+---
+name: Feature request
+about: Suggest an idea for an enhancement or new feature
+---
+
+<!--
+
+Thanks for taking an interest in Scrapy!
+
+If you have a question that starts with "How to...", please see the Scrapy Community page: https://scrapy.org/community/.
+The GitHub issue tracker's purpose is to deal with bug reports and feature requests for the project itself.
+
+Keep in mind that by filing an issue, you are expected to comply with Scrapy's Code of Conduct, including treating everyone with respect: https://github.com/scrapy/scrapy/blob/master/CODE_OF_CONDUCT.md
+
+The following is a suggested template to structure your pull request, you can find more guidelines at https://doc.scrapy.org/en/latest/contributing.html#writing-patches and https://doc.scrapy.org/en/latest/contributing.html#submitting-patches
+
+-->
+
+## Summary
+
+One paragraph explanation of the feature.
+
+## Motivation
+
+Why are we doing this? What use cases does it support? What is the expected outcome?
+
+## Describe alternatives you've considered
+
+A clear and concise description of the alternative solutions you've considered. Be sure to explain why Scrapy's existing customizability isn't suitable for this feature.
+
+## Additional context
+
+Any additional information about the feature request here.

.github/workflows/checks.yml

@@ -0,0 +1,42 @@
+name: Checks
+on: [push, pull_request]
+
+jobs:
+  checks:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: "3.11"
+          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: "3.11"
+          env:
+            TOXENV: twinecheck
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - 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@v3
+    - uses: pre-commit/action@v3.0.0

.github/workflows/publish.yml

@@ -0,0 +1,21 @@
+name: Publish
+on:
+  push:
+    tags:
+      - '[0-9]+.[0-9]+.[0-9]+'
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+      - 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 +1,26 @@
+name: macOS
+on: [push, pull_request]
+
+jobs:
+  tests:
+    runs-on: macos-11
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - 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 +1,75 @@
+name: Ubuntu
+on: [push, pull_request]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: 3.8
+          env:
+            TOXENV: py
+        - python-version: 3.9
+          env:
+            TOXENV: py
+        - python-version: "3.10"
+          env:
+            TOXENV: py
+        - python-version: "3.11"
+          env:
+            TOXENV: py
+        - python-version: "3.11"
+          env:
+            TOXENV: asyncio
+        - python-version: pypy3.9
+          env:
+            TOXENV: pypy3
+
+        # pinned deps
+        - python-version: 3.7.13
+          env:
+            TOXENV: pinned
+        - python-version: 3.7.13
+          env:
+            TOXENV: asyncio-pinned
+        - python-version: pypy3.7
+          env:
+            TOXENV: pypy3-pinned
+        - python-version: 3.7.13
+          env:
+            TOXENV: extra-deps-pinned
+        - python-version: 3.7.13
+          env:
+            TOXENV: botocore-pinned
+
+        - python-version: "3.11"
+          env:
+            TOXENV: extra-deps
+        - python-version: "3.11"
+          env:
+            TOXENV: botocore
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install system libraries
+      if: matrix.python-version == 'pypy3.9' || 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]
+
+jobs:
+  tests:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - python-version: 3.7
+          env:
+            TOXENV: windows-pinned
+        - python-version: 3.8
+          env:
+            TOXENV: py
+        - python-version: 3.9
+          env:
+            TOXENV: py
+        - python-version: "3.10"
+          env:
+            TOXENV: py
+        - python-version: "3.10"
+          env:
+            TOXENV: asyncio
+# no binary package for lxml for 3.11 yet
+#        - python-version: "3.11"
+#          env:
+#            TOXENV: py
+#        - python-version: "3.11"
+#          env:
+#            TOXENV: asyncio
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - 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

@@ -12,6 +12,17 @@ dist
 .idea
 htmlcov/
 .coverage
+.pytest_cache/
+.coverage.*
+coverage.*
+test-output.*
+.cache/
+.mypy_cache/
+/tests/keys/localhost.crt
+/tests/keys/localhost.key
 
 # 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: 5.0.4  # 6.0.0 drops Python 3.7 support
+  hooks:
+  - id: flake8
+- repo: https://github.com/psf/black.git
+  rev: 23.3.0
+  hooks:
+  - id: black
+- repo: https://github.com/pycqa/isort
+  rev: 5.11.5  # 5.12 drops Python 3.7 support
+  hooks:
+  - id: isort
+- repo: https://github.com/adamchainz/blacken-docs
+  rev: 1.13.0
+  hooks:
+  - id: blacken-docs
+    additional_dependencies:
+    - black==23.3.0

.readthedocs.yml

@@ -0,0 +1,17 @@
+version: 2
+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:
+  install:
+    - requirements: docs/requirements.txt
+    - path: .

.travis.yml

@@ -1,37 +0,0 @@
-language: python
-python: 2.7
-sudo: false
-branches:
-  only:
-    - master
-    - /^\d\.\d+$/
-env:
- - TOXENV=py27
- - TOXENV=precise
- - TOXENV=py33
- - TOXENV=docs
-install:
- - 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:
-    - $HOME/.cache/pip
-deploy:
-  provider: pypi
-  distributions: "sdist bdist_wheel"
-  user: scrapy
-  password:
-    secure: JaAKcy1AXWXDK3LXdjOtKyaVPCSFoCGCnW15g4f65E/8Fsi9ZzDfmBa4Equs3IQb/vs/if2SVrzJSr7arN7r9Z38Iv1mUXHkFAyA3Ym8mThfABBzzcUWEQhIHrCX0Tdlx9wQkkhs+PZhorlmRS4gg5s6DzPaeA2g8SCgmlRmFfA=
-  on:
-    tags: true
-    all_branches: true
-    repo: scrapy/scrapy
-    condition: "$TOXENV == py27 && $TRAVIS_TAG =~ ^[0-9]+[.][0-9]+[.][0-9]+(rc[0-9]+)?$"

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

@@ -0,0 +1,133 @@
+
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+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 a positive environment for our
+community include:
+
+* 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 include:
+
+* 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 email address,
+  without their explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Enforcement Responsibilities
+
+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.
+
+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 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 to the community leaders responsible for enforcement at
+opensource@zyte.com.
+All complaints will be reviewed and investigated promptly and fairly.
+
+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 2.1, available at
+[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html][v2.1].
+
+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

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 The guidelines for contributing are available here:
-http://doc.scrapy.org/en/master/contributing.html
+https://docs.scrapy.org/en/master/contributing.html
 
 Please do not abuse the issue tracker for support questions.
 If your issue topic can be rephrased to "How to ...?", please use the
-support channels to get it answered: http://scrapy.org/community/
+support channels to get it answered: https://scrapy.org/community/

INSTALL

@@ -1,4 +0,0 @@
-For information about installing Scrapy see:
-
-* docs/intro/install.rst (local file)
-* http://doc.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)

LICENSE

@@ -4,11 +4,11 @@ All rights reserved.
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:
 
-    1. Redistributions of source code must retain the above copyright notice, 
-       this list of conditions and the following disclaimer.
-    
-    2. Redistributions in binary form must reproduce the above copyright 
-       notice, this list of conditions and the following disclaimer in the
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions, and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions, and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
 
     3. Neither the name of Scrapy nor the names of its contributors may be used

MANIFEST.in

@@ -3,12 +3,24 @@ include AUTHORS
 include INSTALL
 include LICENSE
 include MANIFEST.in
+include NEWS
+
 include scrapy/VERSION
 include scrapy/mime.types
+
+include codecov.yml
+include conftest.py
+include pytest.ini
+include requirements-*.txt
+include tox.ini
+
 recursive-include scrapy/templates *
 recursive-include scrapy license.txt
 recursive-include docs *
 prune docs/build
+
 recursive-include extras *
 recursive-include bin *
 recursive-include tests *
+
+global-exclude __pycache__ *.py[cod]

Makefile.buildbot

@@ -1,24 +0,0 @@
-TRIAL := $(shell which trial)
-BRANCH := $(shell git rev-parse --abbrev-ref HEAD)
-export PYTHONPATH=$(PWD)
-
-test:
-	coverage run --branch $(TRIAL) --reporter=text tests
-	rm -rf htmlcov && coverage html
-	-s3cmd sync -P htmlcov/ s3://static.scrapy.org/coverage-scrapy-$(BRANCH)/
-
-build:
-	git describe --tags --match '[0-9]*' |sed 's/-/.post/;s/-g/+g/' >scrapy/VERSION
-	debchange -m -D unstable --force-distribution -v \
-	  $$(python setup.py --version |sed -r 's/([0-9]+.[0-9]+.[0-9]+)(a|b|rc|dev)([0-9]*)/\1~\2\3/')-$$(date +%s) \
-	  "Automatic build"
-	debuild -us -uc -b
-
-clean:
-	git checkout debian scrapy/VERSION
-	git clean -dfq
-
-pypi:
-	umask 0022 &&  chmod -R a+rX . && python setup.py sdist upload
-
-.PHONY: clean test build

README.rst

@@ -1,3 +1,6 @@
+.. image:: https://scrapy.org/img/scrapylogo.png
+   :target: https://scrapy.org/
+   
 ======
 Scrapy
 ======
@@ -6,26 +9,34 @@ Scrapy
    :target: https://pypi.python.org/pypi/Scrapy
    :alt: PyPI Version
 
-.. image:: https://img.shields.io/pypi/dm/Scrapy.svg
+.. image:: https://img.shields.io/pypi/pyversions/Scrapy.svg
    :target: https://pypi.python.org/pypi/Scrapy
-   :alt: PyPI Monthly downloads
+   :alt: Supported Python Versions
 
-.. image:: https://img.shields.io/travis/scrapy/scrapy/master.svg
-   :target: http://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
    :alt: Wheel Status
-   
-.. image:: http://static.scrapy.org/py3progress/badge.svg
-   :target: https://github.com/scrapy/scrapy/wiki/Python-3-Porting
-   :alt: Python 3 Porting Status
 
 .. image:: https://img.shields.io/codecov/c/github/scrapy/scrapy/master.svg
-   :target: http://codecov.io/github/scrapy/scrapy?branch=master
+   :target: https://codecov.io/github/scrapy/scrapy?branch=master
    :alt: Coverage report
 
+.. image:: https://anaconda.org/conda-forge/scrapy/badges/version.svg
+   :target: https://anaconda.org/conda-forge/scrapy
+   :alt: Conda Version
+
 
 Overview
 ========
@@ -34,53 +45,69 @@ Scrapy is a 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.
 
-For more information including a list of features check the Scrapy homepage at:
-http://scrapy.org
+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 2.7
-* Works on Linux, Windows, Mac OSX, BSD
+* Python 3.7+
+* Works on Linux, Windows, macOS, BSD
 
 Install
 =======
 
-The quick way::
+The quick way:
+
+.. code:: bash
 
     pip install scrapy
 
-For more details see the install section in the documentation:
-http://doc.scrapy.org/en/latest/intro/install.html
-
-Releases
-========
-
-You can download the latest stable and development releases from:
-http://scrapy.org/download/
+See the install section in the documentation at
+https://docs.scrapy.org/en/latest/intro/install.html for more details.
 
 Documentation
 =============
 
-Documentation is available online at http://doc.scrapy.org/ and in the ``docs``
+Documentation is available online at https://docs.scrapy.org/ and in the ``docs``
 directory.
 
+Releases
+========
+
+You can check https://docs.scrapy.org/en/latest/news.html for the release notes.
+
 Community (blog, twitter, mail list, IRC)
 =========================================
 
-See http://scrapy.org/community/
+See https://scrapy.org/community/ for details.
 
 Contributing
 ============
 
-See http://doc.scrapy.org/en/master/contributing.html
+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 <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@zyte.com.
 
 Companies using Scrapy
 ======================
 
-See http://scrapy.org/companies/
+See https://scrapy.org/companies/ for a list.
 
 Commercial Support
 ==================
 
-See http://scrapy.org/support/
+See https://scrapy.org/support/ for details.

artwork/README

@@ -1,19 +0,0 @@
-Scrapy artwork
-==============
-
-This folder contains Scrapy artwork resources such as logos and fonts.
-
-scrapy-logo.jpg
----------------
-
-Main Scrapy logo, in JPEG format.
-
-qlassik.zip 
------------
-
-Font used for Scrapy logo. Homepage: http://www.dafont.com/qlassik.font
-
-scrapy-blog.logo.xcf
---------------------
-
-The logo used in Scrapy blog, in Gimp format.

artwork/README.rst

@@ -0,0 +1,20 @@
+==============
+Scrapy artwork
+==============
+
+This folder contains the Scrapy artwork resources such as logos and fonts.
+
+scrapy-logo.jpg
+---------------
+
+The main Scrapy logo, in JPEG format.
+
+qlassik.zip
+-----------
+
+The font used for the Scrapy logo. Homepage: https://www.dafont.com/qlassik.font
+
+scrapy-blog.logo.xcf
+--------------------
+
+The logo used in the Scrapy blog, in Gimp format.

codecov.yml

@@ -0,0 +1,6 @@
+comment:
+  layout: "header, diff, tree"
+
+coverage:
+  status:
+    project: false

conftest.py

@@ -1,40 +1,82 @@
-import glob
-import six
+from pathlib import Path
+
 import pytest
+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 glob.glob(folder + "/*.py") + glob.glob(folder + "/*/*.py")
+    return (str(p) for p in Path(folder).rglob("*.py"))
 
 
 collect_ignore = [
-    # deprecated or moved modules
-    "scrapy/conf.py",
-    "scrapy/stats.py",
-    "scrapy/project.py",
-    "scrapy/utils/decorator.py",
-    "scrapy/statscol.py",
-    "scrapy/squeue.py",
-    "scrapy/log.py",
-    "scrapy/dupefilter.py",
-    "scrapy/command.py",
-    "scrapy/linkextractor.py",
-    "scrapy/spider.py",
-
     # not a test, but looks like a test
     "scrapy/utils/testsite.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"),
+]
 
-] + _py_files("scrapy/contrib") + _py_files("scrapy/contrib_exp")
-
-
-if six.PY3:
-    for line in open('tests/py3-ignores.txt'):
+with Path("tests/ignores.txt").open(encoding="utf-8") as reader:
+    for line in reader:
         file_path = line.strip()
-        if len(file_path) > 0 and file_path[0] != '#':
+        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()
 def chdir(tmpdir):
     """Change to pytest-provided temporary directory"""
     tmpdir.chdir()
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--reactor",
+        default="default",
+        choices=["default", "asyncio"],
+    )
+
+
+@pytest.fixture(scope="class")
+def reactor_pytest(request):
+    if not request.cls:
+        # doctests
+        return
+    request.cls.reactor_pytest = request.config.getoption("--reactor")
+    return request.cls.reactor_pytest
+
+
+@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")
+
+
+@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")
+
+
+def pytest_configure(config):
+    if config.getoption("--reactor") == "asyncio":
+        install_reactor("twisted.internet.asyncioreactor.AsyncioSelectorReactor")
+
+
+# Generate localhost certificate files, needed by some tests
+generate_keys()

debian/changelog

@@ -1,5 +0,0 @@
-scrapy (0.11) unstable; urgency=low
-
-  * Initial release.
-
- -- Scrapinghub Team <info@scrapinghub.com>  Thu, 10 Jun 2010 17:24:02 -0300

debian/compat

@@ -1 +0,0 @@
-7

debian/control

@@ -1,20 +0,0 @@
-Source: scrapy
-Section: python
-Priority: optional
-Maintainer: Scrapinghub Team <info@scrapinghub.com>
-Build-Depends: debhelper (>= 7.0.50), python (>=2.7), python-twisted, python-w3lib, python-lxml, python-six (>=1.5.2)
-Standards-Version: 3.8.4
-Homepage: http://scrapy.org/
-
-Package: scrapy
-Architecture: all
-Depends: ${python:Depends}, python-lxml, python-twisted, python-openssl,
- python-w3lib (>= 1.8.0), python-queuelib, python-cssselect (>= 0.9), python-six (>=1.5.2)
-Recommends: python-setuptools
-Conflicts: python-scrapy, scrapy-0.25
-Provides: python-scrapy, scrapy-0.25
-Description: Python web crawling and web scraping framework
- Scrapy is a 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.

debian/copyright

@@ -1,40 +0,0 @@
-This package was debianized by the Scrapinghub team <info@scrapinghub.com>.
-
-It was downloaded from http://scrapy.org
-
-Upstream Author: Scrapy Developers
-
-Copyright: 2007-2013 Scrapy Developers
-
-License: bsd
-
-Copyright (c) Scrapy developers.
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without modification,
-are permitted provided that the following conditions are met:
-
-    1. Redistributions of source code must retain the above copyright notice, 
-       this list of conditions and the following disclaimer.
-    
-    2. Redistributions in binary form must reproduce the above copyright 
-       notice, this list of conditions and the following disclaimer in the
-       documentation and/or other materials provided with the distribution.
-
-    3. Neither the name of Scrapy nor the names of its contributors may be used
-       to endorse or promote products derived from this software without
-       specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
-ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
-ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-The Debian packaging is (C) 2010-2013, Scrapinghub <info@scrapinghub.com> and
-is licensed under the BSD, see `/usr/share/common-licenses/BSD'.

debian/pyversions

@@ -1 +0,0 @@
-2.7

debian/rules

@@ -1,5 +0,0 @@
-#!/usr/bin/make -f
-# -*- makefile -*-
-
-%:
-	dh $@

debian/scrapy.docs

@@ -1,2 +0,0 @@
-README.rst
-AUTHORS

debian/scrapy.install

@@ -1,2 +0,0 @@
-extras/scrapy_bash_completion etc/bash_completion.d/
-extras/scrapy_zsh_completion /usr/share/zsh/vendor-completions/_scrapy

debian/scrapy.lintian-overrides

@@ -1,2 +0,0 @@
-new-package-should-close-itp-bug
-extra-license-file usr/share/pyshared/scrapy/xlib/pydispatch/license.txt

debian/scrapy.manpages

@@ -1 +0,0 @@
-extras/scrapy.1

docs/Makefile

@@ -8,9 +8,10 @@ PYTHON       = python
 SPHINXOPTS   =
 PAPER        =
 SOURCES      =
-SHELL        = /bin/bash
+SHELL        = /usr/bin/env bash
 
-ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees -D latex_paper_size=$(PAPER) \
+ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees \
+                -D latex_elements.papersize=$(PAPER) \
                 $(SPHINXOPTS) . build/$(BUILDER) $(SOURCES)
 
 .PHONY: help update build html htmlhelp clean
@@ -81,8 +82,12 @@ pydoc-topics: build
 	@echo "Building finished; now copy build/pydoc-topics/pydoc_topics.py " \
 	      "into the Lib/ directory"
 
+coverage: BUILDER = coverage
+coverage: build
+
 htmlview: html
-	 $(PYTHON) -c "import webbrowser; webbrowser.open('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

@@ -1,3 +1,5 @@
+:orphan:
+
 ======================================
 Scrapy documentation quick start guide
 ======================================
@@ -9,11 +11,11 @@ Setup the environment
 ---------------------
 
 To compile the documentation you need Sphinx Python library. To install it
-and all its dependencies run
+and all its dependencies run the following command from this dir
 
 ::
 
-    pip install 'Sphinx >= 1.3'
+    pip install -r requirements.txt
 
 
 Compile the documentation
@@ -41,7 +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
 
@@ -55,3 +57,12 @@ There is a way to recreate the doc automatically when you make changes, you
 need to install watchdog (``pip install watchdog``) and then use::
 
     make watch
+
+Alternative method using tox
+----------------------------
+
+To compile the documentation to HTML run the following command::
+
+    tox -e docs
+
+Documentation will be generated (in HTML format) inside the ``.tox/docs/tmp/html`` dir.

docs/_ext/scrapydocs.py

@@ -1,9 +1,10 @@
-from docutils.parsers.rst.roles import set_classes
-from docutils import nodes
-from sphinx.util.compat import Directive
-from sphinx.util.nodes import make_refnode
 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
+
 
 class settingslist_node(nodes.General, nodes.Element):
     pass
@@ -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:
-        # [(u'pair', u'SETTING_NAME; setting', u'std:setting-SETTING_NAME', '')]
-        entry_type, info, refid, _ = node['entries'][0]
-        return entry_type == 'pair' and info.endswith('; setting')
+        # [('pair', 'SETTING_NAME; setting', 'std:setting-SETTING_NAME', '')]
+        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]
-    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
 
@@ -71,65 +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/_tests/quotes.html

@@ -0,0 +1,281 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<title>Quotes to Scrape</title>
+    <link rel="stylesheet" href="/static/bootstrap.min.css">
+    <link rel="stylesheet" href="/static/main.css">
+</head>
+<body>
+    <div class="container">
+        <div class="row header-box">
+            <div class="col-md-8">
+                <h1>
+                    <a href="/" style="text-decoration: none">Quotes to Scrape</a>
+                </h1>
+            </div>
+            <div class="col-md-4">
+                <p>
+                
+                    <a href="/login">Login</a>
+                
+                </p>
+            </div>
+        </div>
+    
+
+<div class="row">
+    <div class="col-md-8">
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="change,deep-thoughts,thinking,world" /    > 
+            
+            <a class="tag" href="/tag/change/page/1/">change</a>
+            
+            <a class="tag" href="/tag/deep-thoughts/page/1/">deep-thoughts</a>
+            
+            <a class="tag" href="/tag/thinking/page/1/">thinking</a>
+            
+            <a class="tag" href="/tag/world/page/1/">world</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“It is our choices, Harry, that show what we truly are, far more than our abilities.”</span>
+        <span>by <small class="author" itemprop="author">J.K. Rowling</small>
+        <a href="/author/J-K-Rowling">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="abilities,choices" /    > 
+            
+            <a class="tag" href="/tag/abilities/page/1/">abilities</a>
+            
+            <a class="tag" href="/tag/choices/page/1/">choices</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“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.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="inspirational,life,live,miracle,miracles" /    > 
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+            <a class="tag" href="/tag/life/page/1/">life</a>
+            
+            <a class="tag" href="/tag/live/page/1/">live</a>
+            
+            <a class="tag" href="/tag/miracle/page/1/">miracle</a>
+            
+            <a class="tag" href="/tag/miracles/page/1/">miracles</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“The person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.”</span>
+        <span>by <small class="author" itemprop="author">Jane Austen</small>
+        <a href="/author/Jane-Austen">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="aliteracy,books,classic,humor" /    > 
+            
+            <a class="tag" href="/tag/aliteracy/page/1/">aliteracy</a>
+            
+            <a class="tag" href="/tag/books/page/1/">books</a>
+            
+            <a class="tag" href="/tag/classic/page/1/">classic</a>
+            
+            <a class="tag" href="/tag/humor/page/1/">humor</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“Imperfection is beauty, madness is genius and it&#39;s better to be absolutely ridiculous than absolutely boring.”</span>
+        <span>by <small class="author" itemprop="author">Marilyn Monroe</small>
+        <a href="/author/Marilyn-Monroe">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="be-yourself,inspirational" /    > 
+            
+            <a class="tag" href="/tag/be-yourself/page/1/">be-yourself</a>
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“Try not to become a man of success. Rather become a man of value.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="adulthood,success,value" /    > 
+            
+            <a class="tag" href="/tag/adulthood/page/1/">adulthood</a>
+            
+            <a class="tag" href="/tag/success/page/1/">success</a>
+            
+            <a class="tag" href="/tag/value/page/1/">value</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“It is better to be hated for what you are than to be loved for what you are not.”</span>
+        <span>by <small class="author" itemprop="author">André Gide</small>
+        <a href="/author/Andre-Gide">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="life,love" /    > 
+            
+            <a class="tag" href="/tag/life/page/1/">life</a>
+            
+            <a class="tag" href="/tag/love/page/1/">love</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“I have not failed. I&#39;ve just found 10,000 ways that won&#39;t work.”</span>
+        <span>by <small class="author" itemprop="author">Thomas A. Edison</small>
+        <a href="/author/Thomas-A-Edison">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="edison,failure,inspirational,paraphrased" /    > 
+            
+            <a class="tag" href="/tag/edison/page/1/">edison</a>
+            
+            <a class="tag" href="/tag/failure/page/1/">failure</a>
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+            <a class="tag" href="/tag/paraphrased/page/1/">paraphrased</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“A woman is like a tea bag; you never know how strong it is until it&#39;s in hot water.”</span>
+        <span>by <small class="author" itemprop="author">Eleanor Roosevelt</small>
+        <a href="/author/Eleanor-Roosevelt">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="misattributed-eleanor-roosevelt" /    > 
+            
+            <a class="tag" href="/tag/misattributed-eleanor-roosevelt/page/1/">misattributed-eleanor-roosevelt</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“A day without sunshine is like, you know, night.”</span>
+        <span>by <small class="author" itemprop="author">Steve Martin</small>
+        <a href="/author/Steve-Martin">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="humor,obvious,simile" /    > 
+            
+            <a class="tag" href="/tag/humor/page/1/">humor</a>
+            
+            <a class="tag" href="/tag/obvious/page/1/">obvious</a>
+            
+            <a class="tag" href="/tag/simile/page/1/">simile</a>
+            
+        </div>
+    </div>
+
+    <nav>
+        <ul class="pager">
+            
+            
+            <li class="next">
+                <a href="/page/2/">Next <span aria-hidden="true">&rarr;</span></a>
+            </li>
+            
+        </ul>
+    </nav>
+    </div>
+    <div class="col-md-4 tags-box">
+        
+            <h2>Top Ten tags</h2>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 28px" href="/tag/love/">love</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 26px" href="/tag/inspirational/">inspirational</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 26px" href="/tag/life/">life</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 24px" href="/tag/humor/">humor</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 22px" href="/tag/books/">books</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 14px" href="/tag/reading/">reading</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 10px" href="/tag/friendship/">friendship</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 8px" href="/tag/friends/">friends</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 8px" href="/tag/truth/">truth</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 6px" href="/tag/simile/">simile</a>
+            </span>
+            
+        
+    </div>
+</div>
+
+    </div>
+    <footer class="footer">
+        <div class="container">
+            <p class="text-muted">
+                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>
+            </p>
+        </div>
+    </footer>
+</body>
+</html>

docs/_tests/quotes1.html

@@ -0,0 +1,281 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<title>Quotes to Scrape</title>
+    <link rel="stylesheet" href="/static/bootstrap.min.css">
+    <link rel="stylesheet" href="/static/main.css">
+</head>
+<body>
+    <div class="container">
+        <div class="row header-box">
+            <div class="col-md-8">
+                <h1>
+                    <a href="/" style="text-decoration: none">Quotes to Scrape</a>
+                </h1>
+            </div>
+            <div class="col-md-4">
+                <p>
+                
+                    <a href="/login">Login</a>
+                
+                </p>
+            </div>
+        </div>
+    
+
+<div class="row">
+    <div class="col-md-8">
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="change,deep-thoughts,thinking,world" /    > 
+            
+            <a class="tag" href="/tag/change/page/1/">change</a>
+            
+            <a class="tag" href="/tag/deep-thoughts/page/1/">deep-thoughts</a>
+            
+            <a class="tag" href="/tag/thinking/page/1/">thinking</a>
+            
+            <a class="tag" href="/tag/world/page/1/">world</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“It is our choices, Harry, that show what we truly are, far more than our abilities.”</span>
+        <span>by <small class="author" itemprop="author">J.K. Rowling</small>
+        <a href="/author/J-K-Rowling">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="abilities,choices" /    > 
+            
+            <a class="tag" href="/tag/abilities/page/1/">abilities</a>
+            
+            <a class="tag" href="/tag/choices/page/1/">choices</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“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.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="inspirational,life,live,miracle,miracles" /    > 
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+            <a class="tag" href="/tag/life/page/1/">life</a>
+            
+            <a class="tag" href="/tag/live/page/1/">live</a>
+            
+            <a class="tag" href="/tag/miracle/page/1/">miracle</a>
+            
+            <a class="tag" href="/tag/miracles/page/1/">miracles</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“The person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.”</span>
+        <span>by <small class="author" itemprop="author">Jane Austen</small>
+        <a href="/author/Jane-Austen">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="aliteracy,books,classic,humor" /    > 
+            
+            <a class="tag" href="/tag/aliteracy/page/1/">aliteracy</a>
+            
+            <a class="tag" href="/tag/books/page/1/">books</a>
+            
+            <a class="tag" href="/tag/classic/page/1/">classic</a>
+            
+            <a class="tag" href="/tag/humor/page/1/">humor</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“Imperfection is beauty, madness is genius and it&#39;s better to be absolutely ridiculous than absolutely boring.”</span>
+        <span>by <small class="author" itemprop="author">Marilyn Monroe</small>
+        <a href="/author/Marilyn-Monroe">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="be-yourself,inspirational" /    > 
+            
+            <a class="tag" href="/tag/be-yourself/page/1/">be-yourself</a>
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“Try not to become a man of success. Rather become a man of value.”</span>
+        <span>by <small class="author" itemprop="author">Albert Einstein</small>
+        <a href="/author/Albert-Einstein">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="adulthood,success,value" /    > 
+            
+            <a class="tag" href="/tag/adulthood/page/1/">adulthood</a>
+            
+            <a class="tag" href="/tag/success/page/1/">success</a>
+            
+            <a class="tag" href="/tag/value/page/1/">value</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“It is better to be hated for what you are than to be loved for what you are not.”</span>
+        <span>by <small class="author" itemprop="author">André Gide</small>
+        <a href="/author/Andre-Gide">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="life,love" /    > 
+            
+            <a class="tag" href="/tag/life/page/1/">life</a>
+            
+            <a class="tag" href="/tag/love/page/1/">love</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“I have not failed. I&#39;ve just found 10,000 ways that won&#39;t work.”</span>
+        <span>by <small class="author" itemprop="author">Thomas A. Edison</small>
+        <a href="/author/Thomas-A-Edison">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="edison,failure,inspirational,paraphrased" /    > 
+            
+            <a class="tag" href="/tag/edison/page/1/">edison</a>
+            
+            <a class="tag" href="/tag/failure/page/1/">failure</a>
+            
+            <a class="tag" href="/tag/inspirational/page/1/">inspirational</a>
+            
+            <a class="tag" href="/tag/paraphrased/page/1/">paraphrased</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“A woman is like a tea bag; you never know how strong it is until it&#39;s in hot water.”</span>
+        <span>by <small class="author" itemprop="author">Eleanor Roosevelt</small>
+        <a href="/author/Eleanor-Roosevelt">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="misattributed-eleanor-roosevelt" /    > 
+            
+            <a class="tag" href="/tag/misattributed-eleanor-roosevelt/page/1/">misattributed-eleanor-roosevelt</a>
+            
+        </div>
+    </div>
+
+    <div class="quote" itemscope itemtype="http://schema.org/CreativeWork">
+        <span class="text" itemprop="text">“A day without sunshine is like, you know, night.”</span>
+        <span>by <small class="author" itemprop="author">Steve Martin</small>
+        <a href="/author/Steve-Martin">(about)</a>
+        </span>
+        <div class="tags">
+            Tags:
+            <meta class="keywords" itemprop="keywords" content="humor,obvious,simile" /    > 
+            
+            <a class="tag" href="/tag/humor/page/1/">humor</a>
+            
+            <a class="tag" href="/tag/obvious/page/1/">obvious</a>
+            
+            <a class="tag" href="/tag/simile/page/1/">simile</a>
+            
+        </div>
+    </div>
+
+    <nav>
+        <ul class="pager">
+            
+            
+            <li class="next">
+                <a href="/page/2/">Next <span aria-hidden="true">&rarr;</span></a>
+            </li>
+            
+        </ul>
+    </nav>
+    </div>
+    <div class="col-md-4 tags-box">
+        
+            <h2>Top Ten tags</h2>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 28px" href="/tag/love/">love</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 26px" href="/tag/inspirational/">inspirational</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 26px" href="/tag/life/">life</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 24px" href="/tag/humor/">humor</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 22px" href="/tag/books/">books</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 14px" href="/tag/reading/">reading</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 10px" href="/tag/friendship/">friendship</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 8px" href="/tag/friends/">friends</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 8px" href="/tag/truth/">truth</a>
+            </span>
+            
+            <span class="tag-item">
+            <a class="tag" style="font-size: 6px" href="/tag/simile/">simile</a>
+            </span>
+            
+        
+    </div>
+</div>
+
+    </div>
+    <footer class="footer">
+        <div class="container">
+            <p class="text-muted">
+                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>
+            </p>
+        </div>
+    </footer>
+</body>
+</html>

docs/conf.py

@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-#
 # Scrapy documentation build configuration file, created by
 # sphinx-quickstart on Mon Nov 24 12:02:52 2008.
 #
@@ -12,13 +10,13 @@
 # serve to show the default.
 
 import sys
-from os import path
+from datetime import datetime
+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
@@ -27,25 +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 = [
-    'scrapydocs',
-    'sphinx.ext.autodoc'
+    "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 = u'Scrapy'
-copyright = u'2008-2015, 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
@@ -54,45 +57,51 @@ copyright = u'2008-2015, 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"]
 
 # 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"]
 
 
 # Options for HTML output
@@ -100,19 +109,19 @@ pygments_style = 'sphinx'
 
 # 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
@@ -121,48 +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'
-
-# If true, SmartyPants will be used to convert quotes and dashes to
-# typographically correct entities.
-html_use_smartypants = True
+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
@@ -170,47 +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', ur'Scrapy Documentation',
-   ur'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
@@ -219,6 +227,95 @@ 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/",
 ]
+
+
+# Options for the Coverage extension
+# ----------------------------------
+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$",
+    # ContractsManager is an internal class, developers are not expected to
+    # interact with it directly in any way.
+    r"\bContractsManager\b$",
+    # 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)$",
+    # Methods of downloader middlewares are not documented, only the classes
+    # themselves, since downloader middlewares are controlled through Scrapy
+    # settings.
+    r"^scrapy\.downloadermiddlewares\.\w*?\.(\w*?Middleware|DownloaderStats)\.",
+    # Base classes of downloader middlewares are implementation details that
+    # are not meant for users.
+    r"^scrapy\.downloadermiddlewares\.\w*?\.Base\w*?Middleware",
+    # Private exception used by the command-line interface implementation.
+    r"^scrapy\.exceptions\.UsageError",
+    # Methods of BaseItemExporter subclasses are only documented in
+    # BaseItemExporter.
+    r"^scrapy\.exporters\.(?!BaseItemExporter\b)\w*?\.",
+    # Extension behavior is only modified through settings. Methods of
+    # extension classes, as well as helper functions, are implementation
+    # details that are not documented.
+    r"^scrapy\.extensions\.[a-z]\w*?\.[A-Z]\w*?\.",  # methods
+    r"^scrapy\.extensions\.[a-z]\w*?\.[a-z]",  # helper functions
+    # Never documented before, and deprecated now.
+    r"^scrapy\.linkextractors\.FilteringLinkExtractor$",
+    # Implementation detail of LxmlLinkExtractor
+    r"^scrapy\.linkextractors\.lxmlhtml\.LxmlParserLinkExtractor",
+]
+
+
+# Options for the InterSphinx extension
+# -------------------------------------
+
+intersphinx_mapping = {
+    "attrs": ("https://www.attrs.org/en/stable/", None),
+    "coverage": ("https://coverage.readthedocs.io/en/stable", 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
+# ------------------------------------
+
+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"]
+
+
+def setup(app):
+    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 skip

docs/conftest.py

@@ -0,0 +1,34 @@
+from doctest import ELLIPSIS, NORMALIZE_WHITESPACE
+from pathlib import Path
+
+from sybil import Sybil
+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
+
+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
+
+
+pytest_collect_file = Sybil(
+    parsers=[
+        DocTestParser(optionflags=ELLIPSIS | NORMALIZE_WHITESPACE),
+        PythonCodeBlockParser(future_imports=["print_function"]),
+        skip,
+    ],
+    pattern="*.rst",
+    setup=setup,
+).pytest()

docs/contributing.rst

@@ -6,25 +6,28 @@ Contributing to Scrapy
 
 .. important::
 
-    Double check you are reading the most recent version of this document at
-    http://doc.scrapy.org/en/master/contributing.html
+    Double check that you are reading the most recent version of this document at
+    https://docs.scrapy.org/en/master/contributing.html
 
 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 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.
 
-* Submit patches for new functionality and/or bug fixes. Please read
-  `Writing patches`_ and `Submitting patches`_ below for details on how to
+* Submit patches for new functionalities and/or bug fixes. Please read
+  :ref:`writing-patches` and `Submitting patches`_ below for details on how to
   write and submit a patch.
 
-* Join the `scrapy-users`_ mailing list and share your ideas on how to
+* 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
 ==============
 
@@ -35,33 +38,55 @@ Reporting bugs
     trusted Scrapy developers, and its archives are not public.
 
 Well-written bug reports are very helpful, so keep in mind the following
-guidelines when reporting a new bug.
+guidelines when you're going to report a new bug.
 
 * check the :ref:`FAQ <faq>` first to see if your issue is addressed in a
   well-known question
 
-* check the `open issues`_ to see if it has already been reported. If it has,
-  don't dismiss the report but check the ticket history and comments, you may
-  find additional useful information to contribute.
+* if you have a general question about Scrapy usage, please ask it at
+  `Stack Overflow <https://stackoverflow.com/questions/tagged/scrapy>`__
+  (use "scrapy" tag).
 
-* search the `scrapy-users`_ list to see if it has been discussed there, or
-  if you're not sure if what you're seeing is a bug. You can also ask in the
-  `#scrapy` IRC channel.
+* 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
+  you have additional useful information, please leave a comment, or consider
+  :ref:`sending a pull request <writing-patches>` with a fix.
 
-* write complete, reproducible, specific bug reports. The smaller the test
+* search the `scrapy-users`_ list and `Scrapy subreddit`_ to see if it has
+  been discussed there, or if you're not sure if what you're seeing is a bug.
+  You can also ask in the ``#scrapy`` IRC channel.
+
+* write **complete, reproducible, specific bug reports**. The smaller the test
   case, the better. Remember that other developers won't have your project to
   reproduce the bug, so please include all relevant files required to reproduce
-  it.
+  it. See for example StackOverflow's guide on creating a
+  `Minimal, Complete, and Verifiable example`_ exhibiting the issue.
+
+* the most awesome way to provide a complete reproducible example is to
+  send a pull request which adds a failing test case to the
+  Scrapy testing suite (see :ref:`submitting-patches`).
+  This is helpful even if you don't have an intention to
+  fix the issue yourselves.
 
 * include the output of ``scrapy version -v`` so developers working on your bug
   know exactly which version and platform it occurred on, which is often very
   helpful for reproducing it, or knowing if it was already fixed.
 
+.. _Minimal, Complete, and Verifiable example: https://stackoverflow.com/help/mcve
+
+.. _writing-patches:
+
 Writing patches
 ===============
 
-The better written a patch is, the higher chance that it'll get accepted and
-the sooner that will be merged.
+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:
 
@@ -80,10 +105,26 @@ Well-written patches should:
   the documentation changes in the same patch.  See `Documentation policies`_
   below.
 
+* if you're adding a private API, please add a regular expression to the
+  ``coverage_ignore_pyobjects`` variable of ``docs/conf.py`` to exclude the new
+  private API from documentation coverage checks.
+
+  To see if your private API is skipped properly, generate a documentation
+  coverage report as follows::
+
+      tox -e docs-coverage
+
+* if you are removing deprecated code, first make sure that at least 1 year
+  (12 months) has passed since the release that introduced the deprecation.
+  See :ref:`deprecation-policy`.
+
+
+.. _submitting-patches:
+
 Submitting patches
 ==================
 
-The best way to submit a patch is to issue a `pull request`_ on Github,
+The best way to submit a patch is to issue a `pull request`_ on GitHub,
 optionally creating a new issue first.
 
 Remember to explain what was fixed or the new functionality (what it is, why
@@ -93,83 +134,166 @@ developers to understand and accept your patch.
 You can also discuss the new functionality (or bug fix) before creating the
 patch, but it's always good to have a patch ready to illustrate your arguments
 and show that you have put some additional thought into the subject. A good
-starting point is to send a pull request on Github. It can be simple enough to
+starting point is to send a pull request on GitHub. It can be simple enough to
 illustrate your idea, and leave documentation/tests for later, after the idea
-has been validated and proven useful. Alternatively, you can send an email to
-`scrapy-users`_ to discuss your idea first.
+has been validated and proven useful. Alternatively, you can start a
+conversation in the `Scrapy subreddit`_ to discuss your idea first.
+
+Sometimes there is an existing pull request for the problem you'd like to
+solve, which is stalled for some reason. Often the pull request is in a
+right direction, but changes are requested by Scrapy maintainers, and the
+original pull request author hasn't had time to address them.
+In this case consider picking up this pull request: open
+a new pull request with all commits from the original pull request, as well as
+additional changes to address the raised issues. Doing so helps a lot; it is
+not considered rude as long as the original author is acknowledged by keeping
+his/her commits.
+
+You can pull an existing pull request to a local branch
+by running ``git fetch upstream pull/$PR_NUMBER/head:$BRANCH_NAME_TO_CREATE``
+(replace 'upstream' with a remote name for scrapy repository,
+``$PR_NUMBER`` with an ID of the pull request, and ``$BRANCH_NAME_TO_CREATE``
+with a name of the branch you want to create locally).
+See also: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/checking-out-pull-requests-locally#modifying-an-inactive-pull-request-locally.
+
+When writing GitHub pull requests, try to keep titles short but descriptive.
+E.g. For bug #411: "Scrapy hangs if an exception raises in start_requests"
+prefer "Fix hanging when exception occurs in start_requests (#411)"
+instead of "Fix for #411". Complete titles make it easy to skim through
+the issue tracker.
 
 Finally, try to keep aesthetic changes (:pep:`8` compliance, unused imports
-removal, etc) in separate commits than functional changes. This will make pull
+removal, etc) in separate commits from functional changes. This will make pull
 requests easier to review and more likely to get merged.
 
+
+.. _coding-style:
+
 Coding style
 ============
 
 Please follow these coding conventions when writing code for inclusion in
 Scrapy:
 
-* Unless otherwise specified, follow :pep:`8`.
+* 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``.
 
-* It's OK to use lines longer than 80 chars if it improves the code
-  readability.
+* 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.
 
-* Don't put your name in the code you contribute. Our policy is to keep
-  the contributor's name in the `AUTHORS`_ file distributed with Scrapy.
+.. _scrapy-pre-commit:
 
-Scrapy Contrib
-==============
+Pre-commit
+==========
 
-Scrapy contrib shares a similar rationale as Django contrib, which is explained
-in `this post <http://jacobian.org/writing/what-is-django-contrib/>`_. If you
-are working on a new functionality, please follow that rationale to decide
-whether it should be a Scrapy contrib. If unsure, you can ask in
-`scrapy-users`_.
+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
 ======================
 
-* **Don't** use docstrings for documenting classes, or methods which are
-  already documented in the official (sphinx) documentation. For example, the
-  :meth:`ItemLoader.add_value` method should be documented in the sphinx
-  documentation, not its docstring.
+For reference documentation of API members (classes, methods, etc.) use
+docstrings and make sure that the Sphinx documentation uses the
+:mod:`~sphinx.ext.autodoc` extension to pull the docstrings. API reference
+documentation should follow docstring conventions (`PEP 257`_) and be
+IDE-friendly: short, to the point, and it may provide short examples.
+
+Other types of documentation, such as tutorials or topics, should be covered in
+files within the ``docs/`` directory. This includes documentation that is
+specific to an API member, but goes beyond API reference documentation.
+
+In any case, if something is covered in a docstring, use the
+:mod:`~sphinx.ext.autodoc` extension to pull the docstring into the
+documentation instead of duplicating the docstring in files within the
+``docs/`` directory.
+
+Documentation updates that cover new or modified features must use Sphinx’s
+:rst:dir:`versionadded` and :rst:dir:`versionchanged` directives. Use
+``VERSION`` as version, we will replace it with the actual version right before
+the corresponding release. When we release a new major or minor version of
+Scrapy, we remove these directives if they are older than 3 years.
+
+Documentation about deprecated features must be removed as those features are
+deprecated, so that new readers do not run into it. New deprecations and
+deprecation removals are documented in the :ref:`release notes <news>`.
 
-* **Do** use docstrings for documenting functions not present in the official
-  (sphinx) documentation, such as functions from ``scrapy.utils`` package and
-  its sub-modules.
 
 Tests
 =====
 
-Tests are implemented using the `Twisted unit-testing framework`_, running
-tests requires `tox`_.
+Tests are implemented using the :doc:`Twisted unit-testing framework
+<twisted:development/test-standard>`. Running tests requires
+:doc:`tox <tox:index>`.
+
+.. _running-tests:
 
 Running tests
 -------------
 
-Make sure you have a recent enough `tox`_ installation:
+To run all tests::
 
-    ``tox --version``
-
-If your version is older than 1.7.0, please update it first:
-
-    ``pip install -U tox``
-
-To run all tests go to the root directory of Scrapy source code and run:
-
-    ``tox``
+    tox
 
 To run a specific test (say ``tests/test_loader.py``) use:
 
     ``tox -- tests/test_loader.py``
 
-To see coverage report install `coverage`_ (``pip install coverage``) and run:
+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 3.7 use::
+
+    tox -e py37
+
+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 py37,py38 -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
+default positional arguments defined in ``tox.ini``, so you must include those
+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 3.7 :doc:`tox <tox:index>` environment using all your CPU cores::
+
+    tox -e py37 -- scrapy tests -n auto
+
+To see coverage report install :doc:`coverage <coverage:index>`
+(``pip install coverage``) and run:
 
     ``coverage report``
 
 see output of ``coverage --help`` for more options like html or xml report.
 
-.. _coverage: https://pypi.python.org/pypi/coverage
-
 Writing tests
 -------------
 
@@ -189,9 +313,13 @@ And their unit-tests are in::
 
 .. _issue tracker: https://github.com/scrapy/scrapy/issues
 .. _scrapy-users: https://groups.google.com/forum/#!forum/scrapy-users
-.. _Twisted unit-testing framework: http://twistedmatrix.com/documents/current/core/development/policy/test-standard.html
+.. _Scrapy subreddit: https://reddit.com/r/scrapy
 .. _AUTHORS: https://github.com/scrapy/scrapy/blob/master/AUTHORS
 .. _tests/: https://github.com/scrapy/scrapy/tree/master/tests
 .. _open issues: https://github.com/scrapy/scrapy/issues
-.. _pull request: https://help.github.com/send-pull-requests/
-.. _tox: https://pypi.python.org/pypi/tox
+.. _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

@@ -3,6 +3,8 @@
 Frequently Asked Questions
 ==========================
 
+.. _faq-scrapy-bs-cmp:
+
 How does Scrapy compare to BeautifulSoup or lxml?
 -------------------------------------------------
 
@@ -19,33 +21,53 @@ Python code.
 In other words, comparing `BeautifulSoup`_ (or `lxml`_) to Scrapy is like
 comparing `jinja2`_ to `Django`_.
 
-.. _BeautifulSoup: http://www.crummy.com/software/BeautifulSoup/
-.. _lxml: http://lxml.de/
-.. _jinja2: http://jinja.pocoo.org/
+.. _BeautifulSoup: https://www.crummy.com/software/BeautifulSoup/
+.. _lxml: https://lxml.de/
+.. _jinja2: https://palletsprojects.com/p/jinja/
 .. _Django: https://www.djangoproject.com/
 
-.. _faq-python-versions:
+Can I use Scrapy with BeautifulSoup?
+------------------------------------
 
-What Python versions does Scrapy support?
------------------------------------------
+Yes, you can.
+As mentioned :ref:`above <faq-scrapy-bs-cmp>`, `BeautifulSoup`_ can be used
+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.
 
-Scrapy is supported under Python 2.7 only.
-Python 2.6 support was dropped starting at Scrapy 0.20.
+Here's an example spider using BeautifulSoup API, with ``lxml`` as the HTML parser:
 
-Does Scrapy work with Python 3?
----------------------------------
+.. skip: next
+.. code-block:: python
 
-No, but there are plans to support Python 3.3+.
-At the moment, Scrapy works with Python 2.7.
+    from bs4 import BeautifulSoup
+    import scrapy
+
+
+    class ExampleSpider(scrapy.Spider):
+        name = "example"
+        allowed_domains = ["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}
+
+.. note::
+
+    ``BeautifulSoup`` supports several HTML/XML parsers.
+    See `BeautifulSoup's official documentation`_ on which ones are available.
+
+.. _BeautifulSoup's official documentation: https://www.crummy.com/software/BeautifulSoup/bs4/doc/#specifying-the-parser-to-use
 
-.. seealso:: :ref:`faq-python-versions`.
 
 Did Scrapy "steal" X from Django?
 ---------------------------------
 
 Probably, but we don't like that word. We think Django_ is a great open source
 project and an example to follow, so we've used it as an inspiration for
-Scrapy. 
+Scrapy.
 
 We believe that, if something is already done well, there's no need to reinvent
 it. This concept, besides being one of the foundations for open source and free
@@ -57,8 +79,6 @@ focus on the real problems we need to solve.
 We'd be proud if Scrapy serves as an inspiration for other projects. Feel free
 to steal from us!
 
-.. _Django: https://www.djangoproject.com/
-
 Does Scrapy work with HTTP proxies?
 -----------------------------------
 
@@ -71,31 +91,36 @@ 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: http://sourceforge.net/projects/pywin32/
-.. _this Twisted bug: http://twistedmatrix.com/trac/ticket/3707
-
 How can I simulate a user login in my spider?
 ---------------------------------------------
 
 See :ref:`topics-request-response-ref-request-userlogin`.
 
+.. _faq-bfo-dfo:
+
 Does Scrapy crawl in breadth-first or depth-first order?
 --------------------------------------------------------
 
 By default, Scrapy uses a `LIFO`_ queue for storing pending requests, which
 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::
+in most cases.
+
+If you do want to crawl in true `BFO order`_, you can do it by
+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
+:setting:`CONCURRENT_REQUESTS_PER_IP`, those requests are sent
+concurrently. As a result, the first few requests of a crawl rarely follow the
+desired order. Lowering those settings to ``1`` enforces the desired order, but
+it significantly slows down the crawl as a whole.
+
 
 My Scrapy crawler has memory leaks. What can I do?
 --------------------------------------------------
@@ -110,6 +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?
 --------------------------------------------------
 
@@ -121,7 +183,7 @@ Why does Scrapy download pages in English instead of my native language?
 Try changing the default `Accept-Language`_ request header by overriding the
 :setting:`DEFAULT_REQUEST_HEADERS` setting.
 
-.. _Accept-Language: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
+.. _Accept-Language: https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
 
 Where can I find some example Scrapy projects?
 ----------------------------------------------
@@ -144,7 +206,7 @@ I get "Filtered offsite request" messages. How can I fix them?
 Those messages (logged with ``DEBUG`` level) don't necessarily mean there is a
 problem, so you may not need to fix them.
 
-Those message are thrown by the Offsite Spider Middleware, which is a spider
+Those messages are thrown by the Offsite Spider Middleware, which is a spider
 middleware (enabled by default) whose purpose is to filter out requests to
 domains outside the ones covered by the spider.
 
@@ -169,16 +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
 
@@ -201,15 +267,15 @@ Simplest way to dump all my scraped items into a JSON/CSV/XML file?
 
 To dump into a JSON file::
 
-    scrapy crawl myspider -o items.json
+    scrapy crawl myspider -O items.json
 
 To dump into a CSV file::
 
-    scrapy crawl myspider -o items.csv
+    scrapy crawl myspider -O items.csv
 
 To dump into a XML file::
 
-    scrapy crawl myspider -o items.xml
+    scrapy crawl myspider -O items.xml
 
 For more information see :ref:`topics-feed-exports`
 
@@ -220,7 +286,7 @@ The ``__VIEWSTATE`` parameter is used in sites built with ASP.NET/VB.NET. For
 more info on how it works see `this page`_. Also, here's an `example spider`_
 which scrapes one of these sites.
 
-.. _this page: http://search.cpan.org/~ecarroll/HTML-TreeBuilderX-ASP_NET-0.09/lib/HTML/TreeBuilderX/ASP_NET.pm
+.. _this page: https://metacpan.org/pod/release/ECARROLL/HTML-TreeBuilderX-ASP_NET-0.09/lib/HTML/TreeBuilderX/ASP_NET.pm
 .. _example spider: https://github.com/AmbientLighter/rpn-fas/blob/master/fas/spiders/rnp.py
 
 What's the best way to parse big XML/CSV data feeds?
@@ -280,7 +346,78 @@ 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`.
 
-.. _user agents: http://en.wikipedia.org/wiki/User_agent
-.. _LIFO: http://en.wikipedia.org/wiki/LIFO
-.. _DFO order: http://en.wikipedia.org/wiki/Depth-first_search
-.. _BFO order: http://en.wikipedia.org/wiki/Breadth-first_search
+
+.. _faq-split-item:
+
+How to split an item into multiple items in an item pipeline?
+-------------------------------------------------------------
+
+:ref:`Item pipelines <topics-item-pipeline>` cannot yield multiple items per
+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:
+
+.. code-block:: python
+
+    from copy import deepcopy
+
+    from itemadapter import is_item, ItemAdapter
+
+
+    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"]):
+                        yield deepcopy(item)
+
+Does Scrapy support IPv6 addresses?
+-----------------------------------
+
+Yes, by setting :setting:`DNS_RESOLVER` to ``scrapy.resolver.CachingHostnameResolver``.
+Note that by doing so, you lose the ability to set a specific timeout for DNS requests
+(the value of the :setting:`DNS_TIMEOUT` setting is ignored).
+
+
+.. _faq-specific-reactor:
+
+How to deal with ``<class 'ValueError'>: filedescriptor out of range in select()`` exceptions?
+----------------------------------------------------------------------------------------------
+
+This issue `has been reported`_ to appear when running broad crawls in macOS, where the default
+Twisted reactor is :class:`twisted.internet.selectreactor.SelectReactor`. Switching to a
+different reactor is possible by using the :setting:`TWISTED_REACTOR` setting.
+
+
+.. _faq-stop-response-download:
+
+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, 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
+.. _BFO order: https://en.wikipedia.org/wiki/Breadth-first_search

docs/index.rst

@@ -4,7 +4,15 @@
 Scrapy |version| documentation
 ==============================
 
-This documentation contains everything you need to know about Scrapy.
+Scrapy is a 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.
+
+.. _web crawling: https://en.wikipedia.org/wiki/Web_crawler
+.. _web scraping: https://en.wikipedia.org/wiki/Web_scraping
+
+.. _getting-help:
 
 Getting help
 ============
@@ -13,21 +21,26 @@ Having trouble? We'd like to help!
 
 * Try the :doc:`FAQ <faq>` -- it's got answers to some common questions.
 * Looking for specific information? Try the :ref:`genindex` or :ref:`modindex`.
-* Search for information in the `archives of the scrapy-users mailing list`_, or
-  `post a question`_.
-* Ask a question in the `#scrapy IRC channel`_.
+* Ask or search questions in `StackOverflow using the scrapy tag`_.
+* Ask or search questions in the `Scrapy subreddit`_.
+* 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`_.
 
-.. _archives of the scrapy-users mailing list: https://groups.google.com/forum/#!forum/scrapy-users
-.. _post a question: https://groups.google.com/forum/#!forum/scrapy-users
+.. _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
 ===========
 
 .. toctree::
+   :caption: First steps
    :hidden:
 
    intro/overview
@@ -53,6 +66,7 @@ Basic concepts
 ==============
 
 .. toctree::
+   :caption: Basic concepts
    :hidden:
 
    topics/commands
@@ -68,7 +82,6 @@ Basic concepts
    topics/settings
    topics/exceptions
 
-
 :doc:`topics/commands`
     Learn about the command-line tool used to manage your Scrapy project.
 
@@ -110,13 +123,13 @@ Built-in services
 =================
 
 .. toctree::
+   :caption: Built-in services
    :hidden:
 
    topics/logging
    topics/stats
    topics/email
    topics/telnetconsole
-   topics/webservice
 
 :doc:`topics/logging`
     Learn how to use Python's builtin logging on Scrapy.
@@ -130,14 +143,12 @@ 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
 =========================
 
 .. toctree::
+   :caption: Solving specific problems
    :hidden:
 
    faq
@@ -145,21 +156,22 @@ Solving specific problems
    topics/contracts
    topics/practices
    topics/broad-crawls
-   topics/firefox
-   topics/firebug
+   topics/developer-tools
+   topics/dynamic-content
    topics/leaks
    topics/media-pipeline
-   topics/ubuntu
    topics/deploy
    topics/autothrottle
    topics/benchmarking
    topics/jobs
+   topics/coroutines
+   topics/asyncio
 
 :doc:`faq`
     Get answers to most frequently asked questions.
 
 :doc:`topics/debug`
-    Learn how to debug common problems of your scrapy spider.
+    Learn how to debug common problems of your Scrapy spider.
 
 :doc:`topics/contracts`
     Learn how to use contracts for testing your spiders.
@@ -170,11 +182,11 @@ Solving specific problems
 :doc:`topics/broad-crawls`
     Tune Scrapy for crawling a lot domains in parallel.
 
-:doc:`topics/firefox`
-    Learn how to scrape with Firefox and some useful add-ons.
+:doc:`topics/developer-tools`
+    Learn how to scrape with your browser's developer tools.
 
-:doc:`topics/firebug`
-    Learn how to scrape efficiently using Firebug.
+:doc:`topics/dynamic-content`
+    Read webpage data that is loaded dynamically.
 
 :doc:`topics/leaks`
     Learn how to find and get rid of memory leaks in your crawler.
@@ -182,9 +194,6 @@ Solving specific problems
 :doc:`topics/media-pipeline`
     Download files and/or images associated with your scraped items.
 
-:doc:`topics/ubuntu`
-    Install latest Scrapy packages easily on Ubuntu
-
 :doc:`topics/deploy`
     Deploying your Scrapy spiders and run them in a remote server.
 
@@ -197,12 +206,19 @@ Solving specific problems
 :doc:`topics/jobs`
     Learn how to pause and resume crawls for large spiders.
 
+:doc:`topics/coroutines`
+    Use the :ref:`coroutine syntax <async>`.
+
+:doc:`topics/asyncio`
+    Use :mod:`asyncio` and :mod:`asyncio`-powered libraries.
+
 .. _extending-scrapy:
 
 Extending Scrapy
 ================
 
 .. toctree::
+   :caption: Extending Scrapy
    :hidden:
 
    topics/architecture
@@ -210,9 +226,11 @@ Extending Scrapy
    topics/downloader-middleware
    topics/spider-middleware
    topics/extensions
-   topics/api
    topics/signals
+   topics/scheduler
    topics/exporters
+   topics/components
+   topics/api
 
 
 :doc:`topics/architecture`
@@ -230,20 +248,28 @@ 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
 ============
 
 .. toctree::
+   :caption: All the rest
    :hidden:
 
    news

docs/intro/examples.rst

@@ -5,21 +5,16 @@ Examples
 ========
 
 The best way to learn is with examples, and Scrapy is no exception. For this
-reason, there is an example Scrapy project named dirbot_, that you can use to
-play and learn more about Scrapy. It contains the dmoz spider described in the
-tutorial.
+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
+https://quotes.toscrape.com, one using CSS selectors and another one using XPath
+expressions.
 
-This dirbot_ project is available at: https://github.com/scrapy/dirbot
-
-It contains a README file with a detailed description of the project contents.
+The quotesbot_ project is available at: https://github.com/scrapy/quotesbot.
+You can find more information about it in the project's README.
 
 If you're familiar with git, you can checkout the code. Otherwise you can
-download a tarball or zip file of the project by clicking on `Downloads`_.
+download the project as a zip file by clicking
+`here <https://github.com/scrapy/quotesbot/archive/master.zip>`_.
 
-The `scrapy tag on Snipplr`_ is used for sharing code snippets such as spiders,
-middlewares, extensions, or scripts. Feel free (and encouraged!) to share any
-code there.
-
-.. _dirbot: https://github.com/scrapy/dirbot
-.. _Downloads: https://github.com/scrapy/dirbot/downloads
-.. _scrapy tag on Snipplr: http://snipplr.com/all/tags/scrapy/
+.. _quotesbot: https://github.com/scrapy/quotesbot

docs/intro/install.rst

@@ -4,110 +4,172 @@
 Installation guide
 ==================
 
+.. _faq-python-versions:
+
+Supported Python versions
+=========================
+
+Scrapy requires Python 3.7+, either the CPython implementation (default) or
+the PyPy implementation (see :ref:`python:implementations`).
+
+.. _intro-install-scrapy:
+
 Installing Scrapy
 =================
 
-.. note:: Check :ref:`intro-install-platform-notes` first.
+If you're using `Anaconda`_ or `Miniconda`_, you can install the package from
+the `conda-forge`_ channel, which has up-to-date packages for Linux, Windows
+and macOS.
 
-The installation steps assume that you have the following things installed:
+To install Scrapy using ``conda``, run::
 
-* `Python`_ 2.7
+  conda install -c conda-forge scrapy
 
-* `pip`_ and `setuptools`_ Python packages. Nowadays `pip`_ requires and
-  installs `setuptools`_ if not installed. Python 2.7.9 and later include
-  `pip`_ by default, so you may have it already.
+Alternatively, if you’re already familiar with installation of Python packages,
+you can install Scrapy and its dependencies from PyPI with::
 
-* `lxml`_. Most Linux distributions ships prepackaged versions of lxml.
-  Otherwise refer to http://lxml.de/installation.html
+    pip install Scrapy
 
-* `OpenSSL`_. This comes preinstalled in all operating systems, except Windows
-  where the Python installer ships it bundled.
+We strongly recommend that you install Scrapy in :ref:`a dedicated virtualenv <intro-using-virtualenv>`,
+to avoid conflicting with your system packages.
 
-You can install Scrapy using pip (which is the canonical way to install Python
-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`.
 
-To install using pip::
+For more detailed and platform specifics instructions, as well as
+troubleshooting information, read on.
+
+
+Things that are good to know
+----------------------------
+
+Scrapy is written in pure Python and depends on a few key Python packages (among others):
+
+* `lxml`_, an efficient XML and HTML parser
+* `parsel`_, an HTML/XML data extraction library written on top of lxml,
+* `w3lib`_, a multi-purpose helper for dealing with URLs and web page encodings
+* `twisted`_, an asynchronous networking framework
+* `cryptography`_ and `pyOpenSSL`_, to deal with various network-level security needs
+
+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>`.
+
+In case of any trouble related to these dependencies,
+please refer to their respective installation instructions:
+
+* `lxml installation`_
+* :doc:`cryptography installation <cryptography:installation>`
+
+.. _lxml installation: https://lxml.de/installation.html
+
+
+.. _intro-using-virtualenv:
+
+Using a virtual environment (recommended)
+-----------------------------------------
+
+TL;DR: We recommend installing Scrapy inside a virtual environment
+on all platforms.
+
+Python packages can be installed either globally (a.k.a system wide),
+or in user-space. We do not recommend installing Scrapy system wide.
+
+Instead, we recommend that you install Scrapy within a so-called
+"virtual environment" (:mod:`venv`).
+Virtual environments allow you to not conflict with already-installed Python
+system packages (which could break some of your system tools and scripts),
+and still install packages normally with ``pip`` (without ``sudo`` and the likes).
+
+See :ref:`tut-venv` on how to create your virtual environment.
+
+Once you have created a virtual environment, you can install Scrapy inside it with ``pip``,
+just like any other Python package.
+(See :ref:`platform-specific guides <intro-install-platform-notes>`
+below for non-Python dependencies that you may need to install beforehand).
 
-   pip install Scrapy
 
 .. _intro-install-platform-notes:
 
 Platform specific installation notes
 ====================================
 
+.. _intro-install-windows:
+
 Windows
 -------
 
-* Install Python 2.7 from https://www.python.org/downloads/
+Though it's possible to install Scrapy on Windows using pip, we recommend you
+to install `Anaconda`_ or `Miniconda`_ and use the package from the
+`conda-forge`_ channel, which will avoid most installation issues.
 
-  You need to adjust ``PATH`` environment variable to include paths to
-  the Python executable and additional scripts. The following paths need to be
-  added to ``PATH``::
+Once you've installed `Anaconda`_ or `Miniconda`_, install Scrapy with::
 
-      C:\Python27\;C:\Python27\Scripts\;
+  conda install -c conda-forge scrapy
 
-  To update the ``PATH`` open a Command prompt and run::
+To install Scrapy on Windows using ``pip``:
 
-      c:\python27\python.exe c:\python27\tools\scripts\win_add2path.py
+.. warning::
+    This installation method requires “Microsoft Visual C++” for installing some 
+    Scrapy dependencies, which demands significantly more disk space than Anaconda.
 
-  Close the command prompt window and reopen it so changes take effect, run the
-  following command and check it shows the expected Python version::
+#. Download and execute `Microsoft C++ Build Tools`_ to install the Visual Studio Installer.
 
-      python --version
+#. Run the Visual Studio Installer.
 
-* Install `pywin32` from http://sourceforge.net/projects/pywin32/
+#. Under the Workloads section, select **C++ build tools**.
 
-  Be sure you download the architecture (win32 or amd64) that matches your system
+#. Check the installation details and make sure following packages are selected as optional components:
 
-* *(Only required for Python<2.7.9)* Install `pip`_ from
-  https://pip.pypa.io/en/latest/installing.html
+    * **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))
 
-  Now open a Command prompt to check ``pip`` is installed correctly:: 
+#. Install the Visual Studio Build Tools.
 
-      pip --version
+Now, you should be able to :ref:`install Scrapy <intro-install-scrapy>` using ``pip``.
 
-* At this point Python 2.7 and ``pip`` package manager must be working, let's
-  install Scrapy::
+.. _intro-install-ubuntu:
 
-      pip install Scrapy
+Ubuntu 14.04 or above
+---------------------
 
-Ubuntu 9.10 or above
---------------------
+Scrapy is currently tested with recent-enough versions of lxml,
+twisted and pyOpenSSL, and is compatible with recent Ubuntu distributions.
+But it should support older versions of Ubuntu too, like Ubuntu 14.04,
+albeit with potential issues with TLS connections.
 
 **Don't** use the ``python-scrapy`` package provided by Ubuntu, they are
 typically too old and slow to catch up with latest Scrapy.
 
-Instead, use the official :ref:`Ubuntu Packages <topics-ubuntu>`, which already
-solve all dependencies for you and are continuously updated with the latest bug
-fixes.
 
-If you prefer to build the python dependencies locally instead of relying on
-system packages you'll need to install their required non-python dependencies
-first::
+To install Scrapy on Ubuntu (or Ubuntu-based) systems, you need to install
+these dependencies::
 
-    sudo apt-get install python-dev python-pip libxml2-dev libxslt1-dev zlib1g-dev libffi-dev libssl-dev
+    sudo apt-get install python3 python3-dev python3-pip libxml2-dev libxslt1-dev zlib1g-dev libffi-dev libssl-dev
 
-You can install Scrapy with ``pip`` after that::
+- ``python3-dev``, ``zlib1g-dev``, ``libxml2-dev`` and ``libxslt1-dev``
+  are required for ``lxml``
+- ``libssl-dev`` and ``libffi-dev`` are required for ``cryptography``
 
-    pip install Scrapy
+Inside a :ref:`virtualenv <intro-using-virtualenv>`,
+you can install Scrapy with ``pip`` after that::
+
+    pip install scrapy
 
 .. note::
+    The same non-Python dependencies can be used to install Scrapy in Debian
+    Jessie (8.0) and above.
 
-    The same non-python dependencies can be used to install Scrapy in Debian
-    Wheezy (7.0) and above.
 
-Archlinux
----------
+.. _intro-install-macos:
 
-You can follow the generic instructions or install Scrapy from `AUR Scrapy package`::
-
-    yaourt -S scrapy
-
-Mac OS X
---------
+macOS
+-----
 
 Building Scrapy's dependencies requires the presence of a C compiler and
-development headers. On OS X this is typically provided by Apple’s Xcode
+development headers. On macOS this is typically provided by Apple’s Xcode
 development tools. To install the Xcode command line tools open a terminal
 window and run::
 
@@ -118,14 +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 http://brew.sh/
+  * 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
@@ -143,27 +205,81 @@ solutions:
 
       brew update; brew upgrade python
 
-* *(Optional)* Install Scrapy inside an isolated python environment.
+*   *(Optional)* :ref:`Install Scrapy inside a Python virtual environment
+    <intro-using-virtualenv>`.
 
-  This method is a workaround for the above OS X issue, but it's an overall
+  This method is a workaround for the above macOS issue, but it's an overall
   good practice for managing dependencies and can complement the first method.
 
-  `virtualenv`_ is a tool you can use to create virtual environments in python.
-  We recommended reading a tutorial like
-  http://docs.python-guide.org/en/latest/dev/virtualenvs/ to get started.
-
 After any of these workarounds you should be able to install Scrapy::
 
   pip install Scrapy
 
+
+PyPy
+----
+
+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 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
+issues besides installing build dependencies.
+Installing Scrapy with PyPy on Windows is not tested.
+
+You can check that Scrapy is installed correctly by running ``scrapy bench``.
+If this command gives errors such as
+``TypeError: ... got 2 unexpected keyword arguments``, this means
+that setuptools was unable to pick up one PyPy-specific dependency.
+To fix this issue, run ``pip install 'PyPyDispatcher>=2.1.0'``.
+
+
+.. _intro-install-troubleshooting:
+
+Troubleshooting
+===============
+
+AttributeError: 'module' object has no attribute 'OP_NO_TLSv1_1'
+----------------------------------------------------------------
+
+After you install or upgrade Scrapy, Twisted or pyOpenSSL, you may get an
+exception with the following traceback::
+
+    […]
+      File "[…]/site-packages/twisted/protocols/tls.py", line 63, in <module>
+        from twisted.internet._sslverify import _setAcceptableProtocols
+      File "[…]/site-packages/twisted/internet/_sslverify.py", line 38, in <module>
+        TLSVersion.TLSv1_1: SSL.OP_NO_TLSv1_1,
+    AttributeError: 'module' object has no attribute 'OP_NO_TLSv1_1'
+
+The reason you get this exception is that your system or virtual environment
+has a version of pyOpenSSL that your version of Twisted does not support.
+
+To install a version of pyOpenSSL that your version of Twisted supports,
+reinstall Twisted with the :code:`tls` extra option::
+
+    pip install twisted[tls]
+
+For details, see `Issue #2473 <https://github.com/scrapy/scrapy/issues/2473>`_.
+
 .. _Python: https://www.python.org/
-.. _pip: https://pip.pypa.io/en/latest/installing.html
-.. _easy_install: http://pypi.python.org/pypi/setuptools
-.. _Control Panel: http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/sysdm_advancd_environmnt_addchange_variable.mspx
-.. _lxml: http://lxml.de/
-.. _OpenSSL: https://pypi.python.org/pypi/pyOpenSSL
+.. _pip: https://pip.pypa.io/en/latest/installing/
+.. _lxml: https://lxml.de/index.html
+.. _parsel: https://pypi.org/project/parsel/
+.. _w3lib: https://pypi.org/project/w3lib/
+.. _twisted: https://twistedmatrix.com/trac/
+.. _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: http://brew.sh/
-.. _zsh: http://www.zsh.org/
-.. _virtualenv: https://virtualenv.pypa.io/en/latest/
+.. _homebrew: https://brew.sh/
+.. _zsh: https://www.zsh.org/
+.. _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.
 
@@ -19,74 +19,58 @@ Walk-through of an example spider
 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.
 
-So, here's the code for a spider that follows the links to the top
-voted questions on StackOverflow and scrapes some data from each page::
+Here's the code for a spider that scrapes famous quotes from website
+https://quotes.toscrape.com, following the pagination:
+
+.. code-block:: python
 
     import scrapy
 
 
-    class StackOverflowSpider(scrapy.Spider):
-        name = 'stackoverflow'
-        start_urls = ['http://stackoverflow.com/questions?sort=votes']
+    class QuotesSpider(scrapy.Spider):
+        name = "quotes"
+        start_urls = [
+            "https://quotes.toscrape.com/tag/humor/",
+        ]
 
         def parse(self, response):
-            for href in response.css('.question-summary h3 a::attr(href)'):
-                full_url = response.urljoin(href.extract())
-                yield scrapy.Request(full_url, callback=self.parse_question)
+            for quote in response.css("div.quote"):
+                yield {
+                    "author": quote.xpath("span/small/text()").get(),
+                    "text": quote.css("span.text::text").get(),
+                }
 
-        def parse_question(self, response):
-            yield {
-                'title': response.css('h1 a::text').extract()[0],
-                'votes': response.css('.question .vote-count-post::text').extract()[0],
-                'body': response.css('.question .post-text').extract()[0],
-                'tags': response.css('.question .post-tag::text').extract(),
-                'link': response.url,
-            }
+            next_page = response.css('li.next a::attr("href")').get()
+            if next_page is not None:
+                yield response.follow(next_page, self.parse)
 
-
-Put this in a file, name it to something like ``stackoverflow_spider.py``
+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 stackoverflow_spider.py -o top-stackoverflow-questions.json
+    scrapy runspider quotes_spider.py -o quotes.jsonl
 
+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::
 
-When this finishes you will have in the ``top-stackoverflow-questions.json`` file
-a list of the most upvoted questions in StackOverflow in JSON format, containing the
-title, link, number of upvotes, a list of the tags and the question content in HTML,
-looking like this (reformatted for easier reading)::
-
-    [{
-        "body": "... LONG HTML HERE ...",
-        "link": "http://stackoverflow.com/questions/11227809/why-is-processing-a-sorted-array-faster-than-an-unsorted-array",
-        "tags": ["java", "c++", "performance", "optimization"],
-        "title": "Why is processing a sorted array faster than an unsorted array?",
-        "votes": "9924"
-    },
-    {
-        "body": "... LONG HTML HERE ...",
-        "link": "http://stackoverflow.com/questions/1260748/how-do-i-remove-a-git-submodule",
-        "tags": ["git", "git-submodules"],
-        "title": "How do I remove a Git submodule?",
-        "votes": "1764"
-    },
-    ...]
-
+    {"author": "Jane Austen", "text": "\u201cThe person, be it gentleman or lady, who has not pleasure in a good novel, must be intolerably stupid.\u201d"}
+    {"author": "Steve Martin", "text": "\u201cA day without sunshine is like, you know, night.\u201d"}
+    {"author": "Garrison Keillor", "text": "\u201cAnyone who thinks sitting in church can make you a Christian must also think that sitting in a garage can make you a car.\u201d"}
+    ...
 
 
 What just happened?
 -------------------
 
-When you ran the command ``scrapy runspider somefile.py``, Scrapy looked for a
+When you ran the command ``scrapy runspider quotes_spider.py``, Scrapy looked for a
 Spider definition inside it and ran it through its crawler engine.
 
 The crawl started by making requests to the URLs defined in the ``start_urls``
-attribute (in this case, only the URL for StackOverflow top questions page)
+attribute (in this case, only the URL for quotes in *humor* category)
 and called the default callback method ``parse``, passing the response object as
-an argument. In the ``parse`` callback we extract the links to the
-question pages using a CSS Selector with a custom extension that allows to get
-the value for an attribute. Then we yield a few more requests to be sent,
-registering the method ``parse_question`` as the callback to be called for each
-of them as they finish.
+an argument. In the ``parse`` callback, we loop through the quote elements
+using a CSS Selector, yield a Python dict with the extracted quote text and author,
+look for a link to the next page and schedule another request using the same
+``parse`` method as callback.
 
 Here you notice one of the main advantages about Scrapy: requests are
 :ref:`scheduled and processed asynchronously <topics-architecture>`.  This
@@ -103,10 +87,6 @@ each request, limiting amount of concurrent requests per domain or per IP, and
 even :ref:`using an auto-throttling extension <topics-autothrottle>` that tries
 to figure out these automatically.
 
-Finally, the ``parse_question`` callback scrapes the question data for each
-page yielding a dict, which Scrapy then collects and writes to a JSON file as
-requested in the command line.
-
 .. note::
 
     This is using :ref:`feed exports <topics-feed-exports>` to generate the
@@ -145,12 +125,13 @@ scraping easy and efficient, such as:
   :ref:`pipelines <topics-item-pipeline>`).
 
 * Wide range of built-in extensions and middlewares for handling:
-    * cookies and session handling
-    * HTTP features like compression, authentication, caching
-    * user-agent spoofing
-    * robots.txt
-    * crawl depth restriction
-    * and more
+
+  - cookies and session handling
+  - HTTP features like compression, authentication, caching
+  - user-agent spoofing
+  - robots.txt
+  - crawl depth restriction
+  - and more
 
 * A :ref:`Telnet console <topics-telnetconsole>` for hooking into a Python
   console running inside your Scrapy process, to introspect and debug your
@@ -165,12 +146,12 @@ What's next?
 ============
 
 The next steps for you are to :ref:`install Scrapy <intro-install>`,
-:ref:`follow through the tutorial <intro-tutorial>` to learn how to organize
-your code in Scrapy projects and `join the community`_. Thanks for your
+:ref:`follow through the tutorial <intro-tutorial>` to learn how to create
+a full-blown Scrapy project and `join the community`_. Thanks for your
 interest!
 
-.. _join the community: http://scrapy.org/community/
-.. _web scraping: http://en.wikipedia.org/wiki/Web_scraping
-.. _Amazon Associates Web Services: http://aws.amazon.com/associates/
-.. _Amazon S3: http://aws.amazon.com/s3/
-.. _Sitemaps: http://www.sitemaps.org
+.. _join the community: https://scrapy.org/community/
+.. _web scraping: https://en.wikipedia.org/wiki/Web_scraping
+.. _Amazon Associates Web Services: https://affiliate-program.amazon.com/gp/advertising/api/detail/main.html
+.. _Amazon S3: https://aws.amazon.com/s3/
+.. _Sitemaps: https://www.sitemaps.org/index.html

docs/requirements.txt

@@ -0,0 +1,4 @@
+sphinx==5.0.2
+sphinx-hoverxref==1.1.1
+sphinx-notfound-page==0.8
+sphinx-rtd-theme==1.0.0

docs/topics/api.rst

@@ -4,8 +4,6 @@
 Core API
 ========
 
-.. versionadded:: 0.15
-
 This section documents the Scrapy core API, and it's intended for developers of
 extensions and middlewares.
 
@@ -31,9 +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.
@@ -91,14 +96,16 @@ how you :ref:`configure the downloader middlewares
         provided while constructing the crawler, and it is created after the
         arguments given in the :meth:`crawl` method.
 
-    .. method:: crawl(\*args, \**kwargs)
+    .. method:: crawl(*args, **kwargs)
 
         Starts the crawler by instantiating its spider class with the given
-        `args` and `kwargs` arguments, while setting the execution engine in
+        ``args`` and ``kwargs`` arguments, while setting the execution engine in
         motion.
 
         Returns a deferred that is fired when the crawl is finished.
 
+    .. automethod:: stop
+
 .. autoclass:: CrawlerRunner
    :members:
 
@@ -125,16 +132,14 @@ 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,
+            "project": 20,
+            "spider": 30,
+            "cmdline": 40,
         }
 
     For a detailed explanation on each settings sources, see:
@@ -165,7 +170,7 @@ AddonManager API
 SpiderLoader API
 ================
 
-.. module:: scrapy.loader
+.. module:: scrapy.spiderloader
    :synopsis: The spider loader
 
 .. class:: SpiderLoader
@@ -182,7 +187,8 @@ SpiderLoader API
 
        This class method is used by Scrapy to create an instance of the class.
        It's called with the current project settings, and it loads the spiders
-       found in the modules of the :setting:`SPIDER_MODULES` setting.
+       found recursively in the modules of the :setting:`SPIDER_MODULES`
+       setting.
 
        :param settings: project settings
        :type settings: :class:`~scrapy.settings.Settings` instance
@@ -190,7 +196,7 @@ SpiderLoader API
     .. method:: load(spider_name)
 
        Get the Spider class with the given name. It'll look into the previously
-       loaded spiders for a spider class with name `spider_name` and will raise
+       loaded spiders for a spider class with name ``spider_name`` and will raise
        a KeyError if not found.
 
        :param spider_name: spider class name
@@ -206,7 +212,7 @@ 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:
 
@@ -281,5 +287,3 @@ class (which they all inherit from).
 
         Close the given spider. After this is called, no more specific stats
         can be accessed or collected.
-
-.. _reactor: http://twistedmatrix.com/documents/current/core/howto/reactor-basics.html

docs/topics/architecture.rst

@@ -12,30 +12,86 @@ Overview
 
 The following diagram shows an overview of the Scrapy architecture with its
 components and an outline of the data flow that takes place inside the system
-(shown by the green arrows). A brief description of the components is included
+(shown by the red arrows). A brief description of the components is included
 below with links for more detailed information about them. The data flow is
 also described below.
 
-.. image:: _images/scrapy_architecture.png
+.. _data-flow:
+
+Data flow
+=========
+
+.. image:: _images/scrapy_architecture_02.png
    :width: 700
-   :height: 494
+   :height: 470
    :alt: Scrapy architecture
 
+The data flow in Scrapy is controlled by the execution engine, and goes like
+this:
+
+1. The :ref:`Engine <component-engine>` gets the initial Requests to crawl from the
+   :ref:`Spider <component-spiders>`.
+
+2. The :ref:`Engine <component-engine>` schedules the Requests in the
+   :ref:`Scheduler <component-scheduler>` and asks for the
+   next Requests to crawl.
+
+3. The :ref:`Scheduler <component-scheduler>` returns the next Requests
+   to the :ref:`Engine <component-engine>`.
+
+4. The :ref:`Engine <component-engine>` sends the Requests to the
+   :ref:`Downloader <component-downloader>`, passing through the
+   :ref:`Downloader Middlewares <component-downloader-middleware>` (see
+   :meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_request`).
+
+5. Once the page finishes downloading the
+   :ref:`Downloader <component-downloader>` generates a Response (with
+   that page) and sends it to the Engine, passing through the
+   :ref:`Downloader Middlewares <component-downloader-middleware>` (see
+   :meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_response`).
+
+6. The :ref:`Engine <component-engine>` receives the Response from the
+   :ref:`Downloader <component-downloader>` and sends it to the
+   :ref:`Spider <component-spiders>` for processing, passing
+   through the :ref:`Spider Middleware <component-spider-middleware>` (see
+   :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_input`).
+
+7. The :ref:`Spider <component-spiders>` processes the Response and returns
+   scraped items and new Requests (to follow) to the
+   :ref:`Engine <component-engine>`, passing through the
+   :ref:`Spider Middleware <component-spider-middleware>` (see
+   :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output`).
+
+8. The :ref:`Engine <component-engine>` sends processed items to
+   :ref:`Item Pipelines <component-pipelines>`, then send processed Requests to
+   the :ref:`Scheduler <component-scheduler>` and asks for possible next Requests
+   to crawl.
+
+9. The process repeats (from step 3) until there are no more requests from the
+   :ref:`Scheduler <component-scheduler>`.
+
 Components
 ==========
 
+.. _component-engine:
+
 Scrapy Engine
 -------------
 
 The engine is responsible for controlling the data flow between all components
-of the system, and triggering events when certain actions occur. See the Data
-Flow section below for more details.
+of the system, and triggering events when certain actions occur. See the
+:ref:`Data Flow <data-flow>` section above for more details.
+
+.. _component-scheduler:
 
 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:
 
 Downloader
 ----------
@@ -43,13 +99,16 @@ Downloader
 The Downloader is responsible for fetching web pages and feeding them to the
 engine which, in turn, feeds them to the spiders.
 
+.. _component-spiders:
+
 Spiders
 -------
 
 Spiders are custom classes written by Scrapy users to parse responses and
-extract items (aka scraped items) from them or additional URLs (requests) to
-follow. Each spider is able to handle a specific domain (or group of domains).
-For more information see :ref:`topics-spiders`.
+extract :ref:`items <topics-items>` from them or additional requests to
+follow. For more information see :ref:`topics-spiders`.
+
+.. _component-pipelines:
 
 Item Pipeline
 -------------
@@ -59,57 +118,44 @@ extracted (or scraped) by the spiders. Typical tasks include cleansing,
 validation and persistence (like storing the item in a database). For more
 information see :ref:`topics-item-pipeline`.
 
+.. _component-downloader-middleware:
+
 Downloader middlewares
 ----------------------
 
 Downloader middlewares are specific hooks that sit between the Engine and the
 Downloader and process requests when they pass from the Engine to the
-Downloader, and responses that pass from Downloader to the Engine. They provide
-a convenient mechanism for extending Scrapy functionality by plugging custom
-code. For more information see :ref:`topics-downloader-middleware`.
+Downloader, and responses that pass from Downloader to the Engine.
+
+Use a Downloader middleware if you need to do one of the following:
+
+* process a request just before it is sent to the Downloader
+  (i.e. right before Scrapy sends the request to the website);
+* change received response before passing it to a spider;
+* send a new Request instead of passing received response to a spider;
+* pass response to a spider without fetching a web page;
+* silently drop some requests.
+
+For more information see :ref:`topics-downloader-middleware`.
+
+.. _component-spider-middleware:
 
 Spider middlewares
 ------------------
 
 Spider middlewares are specific hooks that sit between the Engine and the
 Spiders and are able to process spider input (responses) and output (items and
-requests). They provide a convenient mechanism for extending Scrapy
-functionality by plugging custom code. For more information see
-:ref:`topics-spider-middleware`.
+requests).
 
-Data flow
-=========
+Use a Spider middleware if you need to
 
-The data flow in Scrapy is controlled by the execution engine, and goes like
-this:
+* post-process output of spider callbacks - change/add/remove requests or items;
+* post-process start_requests;
+* handle spider exceptions;
+* call errback instead of callback for some of the requests based on response
+  content.
 
-1. The Engine opens a domain, locates the Spider that handles that domain, and
-   asks the spider for the first URLs to crawl.
-
-2. The Engine gets the first URLs to crawl from the Spider and schedules them
-   in the Scheduler, as Requests.
-
-3. The Engine asks the Scheduler for the next URLs to crawl.
-
-4. The Scheduler returns the next URLs to crawl to the Engine and the Engine
-   sends them to the Downloader, passing through the Downloader Middleware
-   (request direction).
-
-5. Once the page finishes downloading the Downloader generates a Response (with
-   that page) and sends it to the Engine, passing through the Downloader
-   Middleware (response direction).
-
-6. The Engine receives the Response from the Downloader and sends it to the
-   Spider for processing, passing through the Spider Middleware (input direction).
-
-7. The Spider processes the Response and returns scraped items and new Requests
-   (to follow) to the Engine.
-
-8. The Engine sends scraped items (returned by the Spider) to the Item Pipeline
-   and Requests (returned by spider) to the Scheduler
-
-9. The process repeats (from step 2) until there are no more requests from the
-   Scheduler, and the Engine closes the domain.
+For more information see :ref:`topics-spider-middleware`.
 
 Event-driven networking
 =======================
@@ -121,12 +167,10 @@ for concurrency.
 For more information about asynchronous programming and Twisted see these
 links:
 
-* `Introduction to Deferreds in Twisted`_
+* :doc:`twisted:core/howto/defer-intro`
 * `Twisted - hello, asynchronous programming`_
 * `Twisted Introduction - Krondo`_
 
-.. _Twisted: http://twistedmatrix.com/trac/
-.. _Introduction to Deferreds in Twisted: http://twistedmatrix.com/documents/current/core/howto/defer-intro.html
-.. _Twisted - hello, asynchronous programming: http://jessenoller.com/2009/02/11/twisted-hello-asynchronous-programming/
-.. _Twisted Introduction - Krondo: http://krondo.com/blog/?page_id=1327/
-
+.. _Twisted: https://twistedmatrix.com/trac/
+.. _Twisted - hello, asynchronous programming: http://jessenoller.com/blog/2009/02/11/twisted-hello-asynchronous-programming/
+.. _Twisted Introduction - Krondo: http://krondo.com/an-introduction-to-asynchronous-programming-and-twisted/

docs/topics/asyncio.rst

@@ -0,0 +1,124 @@
+.. _using-asyncio:
+
+=======
+asyncio
+=======
+
+.. versionadded:: 2.0
+
+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>`.
+
+
+.. _install-asyncio:
+
+Installing the asyncio reactor
+==============================
+
+To enable :mod:`asyncio` support, set the :setting:`TWISTED_REACTOR` setting to
+``'twisted.internet.asyncioreactor.AsyncioSelectorReactor'``.
+
+If you are using :class:`~scrapy.crawler.CrawlerRunner`, you also need to
+install the :class:`~twisted.internet.asyncioreactor.AsyncioSelectorReactor`
+reactor manually. You can do that using
+:func:`~scrapy.utils.reactor.install_reactor`::
+
+    install_reactor('twisted.internet.asyncioreactor.AsyncioSelectorReactor')
+
+
+.. _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.
+
+
+.. _asyncio-windows:
+
+Windows-specific notes
+======================
+
+The Windows implementation of :mod:`asyncio` can use two event loop
+implementations:
+
+-   :class:`~asyncio.SelectorEventLoop`, default before Python 3.8, required
+    when using Twisted.
+
+-   :class:`~asyncio.ProactorEventLoop`, default since Python 3.8, cannot work
+    with Twisted.
+
+So on Python 3.8+ the event loop class needs to be changed.
+
+.. versionchanged:: 2.6.0
+   The event loop class is changed automatically when you change the
+   :setting:`TWISTED_REACTOR` setting or call
+   :func:`~scrapy.utils.reactor.install_reactor`.
+
+To change the event loop class manually, call the following code before
+installing the reactor::
+
+    import asyncio
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+
+You can put this in the same function that installs the reactor, if you do that
+yourself, or in some code that runs before the reactor is installed, e.g.
+``settings.py``.
+
+.. 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
+
+
+.. _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."
+                )

docs/topics/autothrottle.rst

@@ -11,7 +11,7 @@ Design goals
 ============
 
 1. be nicer to sites instead of using default download delay of zero
-2. automatically adjust scrapy to the optimum crawling speed, so the user
+2. automatically adjust Scrapy to the optimum crawling speed, so the user
    doesn't have to tune the download delays to find the optimum one.
    The user only needs to specify the maximum concurrent requests
    it allows, and the extension does the rest.
@@ -88,6 +88,7 @@ The settings used to control the AutoThrottle extension are:
 * :setting:`AUTOTHROTTLE_ENABLED`
 * :setting:`AUTOTHROTTLE_START_DELAY`
 * :setting:`AUTOTHROTTLE_MAX_DELAY`
+* :setting:`AUTOTHROTTLE_TARGET_CONCURRENCY`
 * :setting:`AUTOTHROTTLE_DEBUG`
 * :setting:`CONCURRENT_REQUESTS_PER_DOMAIN`
 * :setting:`CONCURRENT_REQUESTS_PER_IP`

docs/topics/benchmarking.rst

@@ -4,8 +4,6 @@
 Benchmarking
 ============
 
-.. versionadded:: 0.17
-
 Scrapy comes with a simple benchmarking suite that spawns a local HTTP server
 and crawls it at the maximum possible speed. The goal of this benchmarking is
 to get an idea of how Scrapy performs in your hardware, in order to have a
@@ -18,44 +16,71 @@ To run it use::
 
 You should see an output like this::
 
-    2013-05-16 13:08:46-0300 [scrapy] INFO: Scrapy 0.17.0 started (bot: scrapybot)
-    2013-05-16 13:08:47-0300 [scrapy] INFO: Spider opened
-    2013-05-16 13:08:47-0300 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:48-0300 [scrapy] INFO: Crawled 74 pages (at 4440 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:49-0300 [scrapy] INFO: Crawled 143 pages (at 4140 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:50-0300 [scrapy] INFO: Crawled 210 pages (at 4020 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:51-0300 [scrapy] INFO: Crawled 274 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:52-0300 [scrapy] INFO: Crawled 343 pages (at 4140 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:53-0300 [scrapy] INFO: Crawled 410 pages (at 4020 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:54-0300 [scrapy] INFO: Crawled 474 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:55-0300 [scrapy] INFO: Crawled 538 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:56-0300 [scrapy] INFO: Crawled 602 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:57-0300 [scrapy] INFO: Closing spider (closespider_timeout)
-    2013-05-16 13:08:57-0300 [scrapy] INFO: Crawled 666 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
-    2013-05-16 13:08:57-0300 [scrapy] INFO: Dumping Scrapy stats:
-        {'downloader/request_bytes': 231508,
-         'downloader/request_count': 682,
-         'downloader/request_method_count/GET': 682,
-         'downloader/response_bytes': 1172802,
-         'downloader/response_count': 682,
-         'downloader/response_status_count/200': 682,
-         'finish_reason': 'closespider_timeout',
-         'finish_time': datetime.datetime(2013, 5, 16, 16, 8, 57, 985539),
-         'log_count/INFO': 14,
-         'request_depth_max': 34,
-         'response_received_count': 682,
-         'scheduler/dequeued': 682,
-         'scheduler/dequeued/memory': 682,
-         'scheduler/enqueued': 12767,
-         'scheduler/enqueued/memory': 12767,
-         'start_time': datetime.datetime(2013, 5, 16, 16, 8, 47, 676539)}
-    2013-05-16 13:08:57-0300 [scrapy] INFO: Spider closed (closespider_timeout)
+    2016-12-16 21:18:48 [scrapy.utils.log] INFO: Scrapy 1.2.2 started (bot: quotesbot)
+    2016-12-16 21:18:48 [scrapy.utils.log] INFO: Overridden settings: {'CLOSESPIDER_TIMEOUT': 10, 'ROBOTSTXT_OBEY': True, 'SPIDER_MODULES': ['quotesbot.spiders'], 'LOGSTATS_INTERVAL': 1, 'BOT_NAME': 'quotesbot', 'LOG_LEVEL': 'INFO', 'NEWSPIDER_MODULE': 'quotesbot.spiders'}
+    2016-12-16 21:18:49 [scrapy.middleware] INFO: Enabled extensions:
+    ['scrapy.extensions.closespider.CloseSpider',
+     'scrapy.extensions.logstats.LogStats',
+     'scrapy.extensions.telnet.TelnetConsole',
+     'scrapy.extensions.corestats.CoreStats']
+    2016-12-16 21:18:49 [scrapy.middleware] INFO: Enabled downloader middlewares:
+    ['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
+     'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
+     'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
+     'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
+     'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
+     'scrapy.downloadermiddlewares.retry.RetryMiddleware',
+     'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
+     'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
+     'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
+     'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
+     'scrapy.downloadermiddlewares.stats.DownloaderStats']
+    2016-12-16 21:18:49 [scrapy.middleware] INFO: Enabled spider middlewares:
+    ['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
+     'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
+     'scrapy.spidermiddlewares.referer.RefererMiddleware',
+     'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
+     'scrapy.spidermiddlewares.depth.DepthMiddleware']
+    2016-12-16 21:18:49 [scrapy.middleware] INFO: Enabled item pipelines:
+    []
+    2016-12-16 21:18:49 [scrapy.core.engine] INFO: Spider opened
+    2016-12-16 21:18:49 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:50 [scrapy.extensions.logstats] INFO: Crawled 70 pages (at 4200 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:51 [scrapy.extensions.logstats] INFO: Crawled 134 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:52 [scrapy.extensions.logstats] INFO: Crawled 198 pages (at 3840 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:53 [scrapy.extensions.logstats] INFO: Crawled 254 pages (at 3360 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:54 [scrapy.extensions.logstats] INFO: Crawled 302 pages (at 2880 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:55 [scrapy.extensions.logstats] INFO: Crawled 358 pages (at 3360 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:56 [scrapy.extensions.logstats] INFO: Crawled 406 pages (at 2880 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:57 [scrapy.extensions.logstats] INFO: Crawled 438 pages (at 1920 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:58 [scrapy.extensions.logstats] INFO: Crawled 470 pages (at 1920 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:18:59 [scrapy.core.engine] INFO: Closing spider (closespider_timeout)
+    2016-12-16 21:18:59 [scrapy.extensions.logstats] INFO: Crawled 518 pages (at 2880 pages/min), scraped 0 items (at 0 items/min)
+    2016-12-16 21:19:00 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
+    {'downloader/request_bytes': 229995,
+     'downloader/request_count': 534,
+     'downloader/request_method_count/GET': 534,
+     'downloader/response_bytes': 1565504,
+     'downloader/response_count': 534,
+     'downloader/response_status_count/200': 534,
+     'finish_reason': 'closespider_timeout',
+     'finish_time': datetime.datetime(2016, 12, 16, 16, 19, 0, 647725),
+     'log_count/INFO': 17,
+     'request_depth_max': 19,
+     'response_received_count': 534,
+     'scheduler/dequeued': 533,
+     'scheduler/dequeued/memory': 533,
+     'scheduler/enqueued': 10661,
+     'scheduler/enqueued/memory': 10661,
+     'start_time': datetime.datetime(2016, 12, 16, 16, 18, 49, 799869)}
+    2016-12-16 21:19:00 [scrapy.core.engine] INFO: Spider closed (closespider_timeout)
 
-That tells you that Scrapy is able to crawl about 3900 pages per minute in the
+That tells you that Scrapy is able to crawl about 3000 pages per minute in the
 hardware where you run it. Note that this is a very simple spider intended to
 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

@@ -20,7 +20,7 @@ These are some common properties often found in broad crawls:
 
 * they crawl many domains (often, unbounded) instead of a specific set of sites
 
-* they don't necessarily crawl domains to completion, because it would
+* they don't necessarily crawl domains to completion, because it would be
   impractical (or impossible) to do so, and instead limit the crawl by time or
   number of pages crawled
 
@@ -34,29 +34,59 @@ These are some common properties often found in broad crawls:
 
 As said above, Scrapy default settings are optimized for focused crawls, not
 broad crawls. However, due to its asynchronous architecture, Scrapy is very
-well suited for performing fast broad crawls. This page summarize some things
+well suited for performing fast broad crawls. This page summarizes some things
 you need to keep in mind when using Scrapy for doing broad crawls, along with
 concrete suggestions of Scrapy settings to tune in order to achieve an
 efficient broad crawl.
 
+.. _broad-crawls-scheduler-priority-queue:
+
+Use the right :setting:`SCHEDULER_PRIORITY_QUEUE`
+=================================================
+
+Scrapy’s default scheduler priority queue is ``'scrapy.pqueues.ScrapyPriorityQueue'``.
+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:
+
+.. code-block:: python
+
+    SCHEDULER_PRIORITY_QUEUE = "scrapy.pqueues.DownloaderAwarePriorityQueue"
+
+.. _broad-crawls-concurrency:
+
 Increase concurrency
 ====================
 
 Concurrency is the number of requests that are processed in parallel. There is
-a global limit and a per-domain limit.
+a global limit (:setting:`CONCURRENT_REQUESTS`) and an additional limit that
+can be set either per domain (:setting:`CONCURRENT_REQUESTS_PER_DOMAIN`) or per
+IP (:setting:`CONCURRENT_REQUESTS_PER_IP`).
+
+.. note:: The scheduler priority queue :ref:`recommended for broad crawls
+          <broad-crawls-scheduler-priority-queue>` does not support
+          :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 you crawler will have available. A
-good starting point is ``100``, but the best way to find out is by doing some
-trials and identifying at what concurrency your Scrapy process gets CPU
-bounded. For optimum performance, You should pick a concurrency where CPU usage
-is at 80-90%.
+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 your crawler will have
+available.
 
-To increase the global concurrency use::
+A good starting point is ``100``:
+
+.. code-block:: python
 
     CONCURRENT_REQUESTS = 100
 
+But the best way to find out is by doing some trials and identifying at what
+concurrency your Scrapy process gets CPU bounded. For optimum performance, you
+should pick a concurrency where CPU usage is at 80-90%.
+
+Increasing concurrency also increases memory usage. If memory usage is a
+concern, you might need to lower your global concurrency limit accordingly.
+
+
 Increase Twisted IO thread pool maximum size
 ============================================
 
@@ -66,7 +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
 
@@ -85,12 +117,14 @@ When doing broad crawls you are often only interested in the crawl rates you
 get and any errors found. These stats are reported by Scrapy when using the
 ``INFO`` log level. In order to save CPU (and log storage requirements) you
 should not use ``DEBUG`` log level when preforming large broad crawls in
-production. Using ``DEBUG`` level when developing your (broad) crawler may fine
-though.
+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
 ===============
@@ -100,7 +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
 
@@ -112,7 +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
 
@@ -123,7 +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
 
@@ -136,7 +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
 
@@ -153,7 +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
 
@@ -162,4 +206,33 @@ AjaxCrawlMiddleware helps to crawl them correctly.
 It is turned OFF by default because it has some performance overhead,
 and enabling it for focused crawls doesn't make much sense.
 
-.. _ajax crawlable: https://developers.google.com/webmasters/ajax-crawling/docs/getting-started
+.. _ajax crawlable: https://developers.google.com/search/docs/ajax-crawling/docs/getting-started
+
+.. _broad-crawls-bfo:
+
+Crawl in BFO order
+==================
+
+:ref:`Scrapy crawls in DFO order by default <faq-bfo-dfo>`.
+
+In broad crawls, however, page crawling tends to be faster than page
+processing. As a result, unprocessed early requests stay in memory until the
+final depth is reached, which can significantly increase memory usage.
+
+:ref:`Crawl in BFO order <faq-bfo-dfo>` instead to save memory.
+
+
+Be mindful of memory leaks
+==========================
+
+If your broad crawl shows a high memory usage, in addition to :ref:`crawling in
+BFO order <broad-crawls-bfo>` and :ref:`lowering concurrency
+<broad-crawls-concurrency>` you should :ref:`debug your memory leaks
+<topics-leaks>`.
+
+
+Install a specific Twisted reactor
+==================================
+
+If the crawl is exceeding the system's capabilities, you might want to try
+installing a specific Twisted reactor, via the :setting:`TWISTED_REACTOR` setting.

docs/topics/commands.rst

@@ -1,11 +1,11 @@
+.. highlight:: none
+
 .. _topics-commands:
 
 =================
 Command line tool
 =================
 
-.. versionadded:: 0.10
-
 Scrapy is controlled through the ``scrapy`` command-line tool, to be referred
 here as the "Scrapy tool" to differentiate it from the sub-commands, which we
 just call "commands" or "Scrapy commands".
@@ -27,7 +27,7 @@ in standard locations:
 1. ``/etc/scrapy.cfg`` or ``c:\scrapy\scrapy.cfg`` (system-wide),
 2. ``~/.config/scrapy.cfg`` (``$XDG_CONFIG_HOME``) and ``~/.scrapy.cfg`` (``$HOME``)
    for global (user-wide) settings, and
-3. ``scrapy.cfg`` inside a scrapy project's root (see next section).
+3. ``scrapy.cfg`` inside a Scrapy project's root (see next section).
 
 Settings from these files are merged in the listed order of preference:
 user-defined values have higher priority than system-wide defaults
@@ -37,7 +37,7 @@ Scrapy also understands, and can be configured through, a number of environment
 variables. Currently these are:
 
 * ``SCRAPY_SETTINGS_MODULE`` (see :ref:`topics-settings-module-envvar`)
-* ``SCRAPY_PROJECT``
+* ``SCRAPY_PROJECT`` (see :ref:`topics-project-envvar`)
 * ``SCRAPY_PYTHON_SHELL`` (see :ref:`topics-shell`)
 
 .. _topics-project-structure:
@@ -55,6 +55,7 @@ structure by default, similar to this::
    myproject/
        __init__.py
        items.py
+       middlewares.py
        pipelines.py
        settings.py
        spiders/
@@ -65,11 +66,42 @@ structure by default, similar to this::
 
 The directory where the ``scrapy.cfg`` file resides is known as the *project
 root directory*. That file contains the name of the python module that defines
-the project settings. Here is an example::
+the project settings. Here is an example:
+
+.. code-block:: ini
 
     [settings]
     default = myproject.settings
 
+.. _topics-project-envvar:
+
+Sharing the root directory between projects
+===========================================
+
+A project root directory, the one that contains the ``scrapy.cfg``, may be
+shared by multiple Scrapy projects, each with its own settings module.
+
+In that case, you must define one or more aliases for those settings modules
+under ``[settings]`` in your ``scrapy.cfg`` file:
+
+.. code-block:: ini
+
+    [settings]
+    default = myproject1.settings
+    project1 = myproject1.settings
+    project2 = myproject2.settings
+
+By default, the ``scrapy`` command-line tool will use the ``default`` settings.
+Use the ``SCRAPY_PROJECT`` environment variable to specify a different project
+for ``scrapy`` to use::
+
+    $ scrapy settings --get BOT_NAME
+    Project 1 Bot
+    $ export SCRAPY_PROJECT=project2
+    $ scrapy settings --get BOT_NAME
+    Project 2 Bot
+
+
 Using the ``scrapy`` tool
 =========================
 
@@ -103,13 +135,14 @@ Creating projects
 The first thing you typically do with the ``scrapy`` tool is create your Scrapy
 project::
 
-    scrapy startproject myproject
+    scrapy startproject myproject [project_dir]
 
-That will create a Scrapy project under the ``myproject`` directory.
+That will create a Scrapy project under the ``project_dir`` directory.
+If ``project_dir`` wasn't specified, ``project_dir`` will be the same as ``myproject``.
 
 Next, you go inside the new project directory::
 
-    cd myproject
+    cd project_dir
 
 And you're ready to use the ``scrapy`` command to manage and control your
 project from there.
@@ -159,6 +192,7 @@ settings).
 Global commands:
 
 * :command:`startproject`
+* :command:`genspider`
 * :command:`settings`
 * :command:`runspider`
 * :command:`shell`
@@ -173,7 +207,6 @@ Project-only commands:
 * :command:`list`
 * :command:`edit`
 * :command:`parse`
-* :command:`genspider`
 * :command:`bench`
 
 .. command:: startproject
@@ -181,11 +214,12 @@ Project-only commands:
 startproject
 ------------
 
-* Syntax: ``scrapy startproject <project_name>``
+* Syntax: ``scrapy startproject <project_name> [project_dir]``
 * Requires project: *no*
 
-Creates a new Scrapy project named ``project_name``, under the ``project_name``
+Creates a new Scrapy project named ``project_name``, under the ``project_dir``
 directory.
+If ``project_dir`` wasn't specified, ``project_dir`` will be the same as ``project_name``.
 
 Usage example::
 
@@ -196,15 +230,13 @@ Usage example::
 genspider
 ---------
 
-* Syntax: ``scrapy genspider [-t template] <name> <domain>``
-* Requires project: *yes*
+* Syntax: ``scrapy genspider [-t template] <name> <domain or URL>``
+* Requires project: *no*
 
-Create a new spider in the current project.
+.. versionadded:: 2.6.0
+   The ability to pass a URL instead of a domain.
 
-This is just a convenience shortcut command for creating spiders based on
-pre-defined templates, but certainly not the only way to create spiders. You
-can just create the spider source code files yourself, instead of using this
-command.
+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::
 
@@ -215,22 +247,16 @@ Usage example::
       csvfeed
       xmlfeed
 
-    $ scrapy genspider -d basic
-    import scrapy
+    $ scrapy genspider example example.com
+    Created spider 'example' using template 'basic'
 
-    class $classname(scrapy.Spider):
-        name = "$name"
-        allowed_domains = ["$domain"]
-        start_urls = (
-            'http://www.$domain/',
-            )
+    $ scrapy genspider -t crawl scrapyorg scrapy.org
+    Created spider 'scrapyorg' using template 'crawl'
 
-        def parse(self, response):
-            pass
-
-    $ scrapy genspider -t basic example example.com
-    Created spider 'example' using template 'basic' in module:
-      mybot.spiders.example
+This is just a convenience shortcut command for creating spiders based on
+pre-defined templates, but certainly not the only way to create spiders. You
+can just create the spider source code files yourself, instead of using this
+command.
 
 .. command:: crawl
 
@@ -242,11 +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
 
@@ -258,6 +304,8 @@ check
 
 Run contract checks.
 
+.. skip: start
+
 Usage examples::
 
     $ scrapy check -l
@@ -275,6 +323,8 @@ Usage examples::
     [FAILED] first_spider:parse
     >>> Returned 92 requests, expected 0..4
 
+.. skip: end
+
 .. command:: list
 
 list
@@ -300,12 +350,12 @@ edit
 * Syntax: ``scrapy edit <spider>``
 * Requires project: *yes*
 
-Edit the given spider using the editor defined in the :setting:`EDITOR`
-setting.
+Edit the given spider using the editor defined in the ``EDITOR`` environment
+variable or (if unset) the :setting:`EDITOR` setting.
 
 This command is provided only as a convenience shortcut for the most common
 case, the developer is of course free to choose any tool or IDE to write and
-debug his spiders.
+debug spiders.
 
 Usage example::
 
@@ -331,6 +381,14 @@ So this command can be used to "see" how your spider would fetch a certain page.
 If used outside a project, no particular per-spider behaviour would be applied
 and it will just use the default Scrapy downloader settings.
 
+Supported options:
+
+* ``--spider=SPIDER``: bypass spider autodetection and force use of specific spider
+
+* ``--headers``: print the response's HTTP headers instead of the response's body
+
+* ``--no-redirect``: do not follow HTTP 3xx redirects (default is to follow them)
+
 Usage examples::
 
     $ scrapy fetch --nolog http://www.example.com/some/page.html
@@ -359,6 +417,12 @@ Opens the given URL in a browser, as your Scrapy spider would "see" it.
 Sometimes spiders see pages differently from regular users, so this can be used
 to check what the spider "sees" and confirm it's what you expect.
 
+Supported options:
+
+* ``--spider=SPIDER``: bypass spider autodetection and force use of specific spider
+
+* ``--no-redirect``: do not follow HTTP 3xx redirects (default is to follow them)
+
 Usage example::
 
     $ scrapy view http://www.example.com/some/page.html
@@ -373,13 +437,38 @@ shell
 * Requires project: *no*
 
 Starts the Scrapy shell for the given URL (if given) or empty if no URL is
-given. See :ref:`topics-shell` for more info.
+given. Also supports UNIX-style local file paths, either relative with
+``./`` or ``../`` prefixes or absolute file paths.
+See :ref:`topics-shell` for more info.
+
+Supported options:
+
+* ``--spider=SPIDER``: bypass spider autodetection and force use of specific spider
+
+* ``-c code``: evaluate the code in the shell, print the result and exit
+
+* ``--no-redirect``: do not follow HTTP 3xx redirects (default is to follow them);
+  this only affects the URL you may pass as argument on the command line;
+  once you are inside the shell, ``fetch(url)`` will still follow HTTP redirects by default.
 
 Usage example::
 
     $ scrapy shell http://www.example.com/some/page.html
     [ ... scrapy shell starts ... ]
 
+    $ scrapy shell --nolog http://www.example.com/ -c '(response.status, response.url)'
+    (200, 'http://www.example.com/')
+
+    # shell follows HTTP redirects by default
+    $ scrapy shell --nolog http://httpbin.org/redirect-to?url=http%3A%2F%2Fexample.com%2F -c '(response.status, response.url)'
+    (200, 'http://example.com/')
+
+    # you can disable this with --no-redirect
+    # (only for the URL passed as command line argument)
+    $ scrapy shell --no-redirect --nolog http://httpbin.org/redirect-to?url=http%3A%2F%2Fexample.com%2F -c '(response.status, response.url)'
+    (302, 'http://httpbin.org/redirect-to?url=http%3A%2F%2Fexample.com%2F')
+
+
 .. command:: parse
 
 parse
@@ -400,6 +489,12 @@ Supported options:
 * ``--callback`` or ``-c``: spider method to use as callback for parsing the
   response
 
+* ``--meta`` or ``-m``: additional request meta that will be passed to the callback
+  request. This must be a valid json string. Example: --meta='{"foo" : "bar"}'
+
+* ``--cbkwargs``: additional keyword arguments that will be passed to the callback.
+  This must be a valid json string. Example: --cbkwargs='{"foo" : "bar"}'
+
 * ``--pipelines``: process items through pipelines
 
 * ``--rules`` or ``-r``: use :class:`~scrapy.spiders.CrawlSpider`
@@ -417,6 +512,12 @@ Supported options:
 
 * ``--verbose`` or ``-v``: display information for each depth level
 
+* ``--output`` or ``-o``: dump scraped items to a file
+
+  .. versionadded:: 2.3
+
+.. skip: start
+
 Usage example::
 
     $ scrapy parse http://www.example.com/ -c parse_item
@@ -424,13 +525,15 @@ Usage example::
 
     >>> STATUS DEPTH LEVEL 1 <<<
     # Scraped Items  ------------------------------------------------------------
-    [{'name': u'Example item',
-     'category': u'Furniture',
-     'length': u'12 cm'}]
+    [{'name': 'Example item',
+     'category': 'Furniture',
+     'length': '12 cm'}]
 
     # Requests  -----------------------------------------------------------------
     []
 
+.. skip: end
+
 
 .. command:: settings
 
@@ -484,8 +587,6 @@ and Platform info, which is useful for bug reports.
 bench
 -----
 
-.. versionadded:: 0.17
-
 * Syntax: ``scrapy bench``
 * Requires project: *no*
 
@@ -509,29 +610,34 @@ Default: ``''`` (empty string)
 A module to use for looking up custom Scrapy commands. This is used to add custom
 commands for your Scrapy project.
 
-Example::
+Example:
 
-    COMMANDS_MODULE = 'mybot.commands'
+.. code-block:: python
 
-.. _Deploying your project: http://scrapyd.readthedocs.org/en/latest/deploy.html
+    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.
 
-The following example adds ``my_command`` command::
+The following example adds ``my_command`` command:
+
+.. skip: next
+
+.. code-block:: python
 
   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 pkg_resources import 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

@@ -4,12 +4,6 @@
 Spiders Contracts
 =================
 
-.. versionadded:: 0.15
-
-.. note:: This is a new feature (introduced in Scrapy 0.15) and may be subject
-   to minor functionality/API updates. Check the :ref:`release notes <news>` to
-   be notified of updates.
-
 Testing spiders can get particularly annoying and while nothing prevents you
 from writing unit tests the task gets cumbersome quickly. Scrapy offers an
 integrated way of testing your spiders by the means of contracts.
@@ -17,10 +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
@@ -35,12 +32,20 @@ This callback is tested using three built-in contracts:
 
 .. class:: UrlContract
 
-    This contract (``@url``) sets the sample url used when checking other
+    This contract (``@url``) sets the sample URL used when checking other
     contract conditions for this spider. This contract is mandatory. All
     callbacks lacking this contract are ignored when running the checks::
 
     @url url
 
+.. class:: CallbackKeywordArgumentsContract
+
+    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.
+    ::
+
+    @cb_kwargs {"arg1": "value1", "arg2": "value2", ...}
+
 .. class:: ReturnsContract
 
     This contract (``@returns``) sets lower and upper bounds for the items and
@@ -60,24 +65,26 @@ Use the :command:`check` command to run the contract checks.
 Custom Contracts
 ================
 
-If you find you need more power than the built-in scrapy contracts you can
+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
+Each contract must inherit from :class:`~scrapy.contracts.Contract` and can
 override three methods:
 
 .. module:: scrapy.contracts
 
-.. class:: Contract(method, \*args)
+.. class:: Contract(method, *args)
 
     :param method: callback function to which the contract is associated
-    :type method: function
+    :type method: collections.abc.Callable
 
     :param args: list of arguments passed into the docstring (whitespace
         separated)
@@ -86,8 +93,11 @@ override three methods:
     .. method:: Contract.adjust_request_args(args)
 
         This receives a ``dict`` as an argument containing default arguments
-        for :class:`~scrapy.http.Request` object. Must return the same or a
-        modified version of it.
+        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.
+
+        Must return the same or a modified version of it.
 
     .. method:: Contract.pre_process(response)
 
@@ -97,23 +107,55 @@ 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
+:class:`~scrapy.contracts.Contract.post_process` if expectations are not met:
+
+.. autoclass:: scrapy.exceptions.ContractFail
 
 Here is a demo contract which checks the presence of a custom header in the
-response received. Raise :class:`scrapy.exceptions.ContractFail` in order to
-get the failures pretty printed::
+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:
+
+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:
+
+.. code-block:: python
+
+    import os
+    import scrapy
+
+
+    class ExampleSpider(scrapy.Spider):
+        name = "example"
+
+        def __init__(self):
+            if os.environ.get("SCRAPY_CHECK"):
+                pass  # Do some scraper adjustments when a check is running

docs/topics/coroutines.rst

@@ -0,0 +1,286 @@
+.. _topics-coroutines:
+
+==========
+Coroutines
+==========
+
+.. versionadded:: 2.0
+
+Scrapy has :ref:`partial support <coroutine-support>` for the
+:ref:`coroutine syntax <async>`.
+
+.. _coroutine-support:
+
+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.Request` callbacks.
+
+    If you are using any custom or third-party :ref:`spider middleware
+    <topics-spider-middleware>`, see :ref:`sync-async-spider-middleware`.
+
+    .. 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>`.
+
+-   The
+    :meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_request`,
+    :meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_response`,
+    and
+    :meth:`~scrapy.downloadermiddlewares.DownloaderMiddleware.process_exception`
+    methods of
+    :ref:`downloader middlewares <topics-downloader-middleware-custom>`.
+
+-   :ref:`Signal handlers that support deferreds <signal-deferred>`.
+
+-   The
+    :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output`
+    method of :ref:`spider middlewares <topics-spider-middleware>`.
+
+    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
+            return item
+
+        def process_item(self, item, spider):
+            adapter = ItemAdapter(item)
+            dfd = db.get_some_data(adapter["id"])
+            dfd.addCallback(self._update_item, item)
+            return dfd
+
+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"])
+            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:
+
+.. skip: next
+.. code-block:: python
+
+    class MySpiderDeferred(Spider):
+        # ...
+        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
+
+
+    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 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,
+  pipelines and middlewares);
+* 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 :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

@@ -5,37 +5,44 @@ 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`
             for item_url in item_urls:
                 yield scrapy.Request(item_url, self.parse_item)
 
         def parse_item(self, response):
+            # <processing code not shown>
             item = MyItem()
             # populate `item` fields
             # and extract item_details_url
-            yield scrapy.Request(item_details_url, self.parse_details, meta={'item': item})
+            yield scrapy.Request(
+                item_details_url, self.parse_details, cb_kwargs={"item": item}
+            )
 
-        def parse_details(self, response):
-            item = response.meta['item']
+        def parse_details(self, response, item):
             # populate more `item` fields
             return item
 
 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 ``meta`` functionality of :class:`~scrapy.http.Request` to pass a
+use the ``cb_kwargs`` functionality of :class:`~scrapy.Request` to pass a
 partially populated item.
 
 
@@ -47,6 +54,10 @@ The most basic way of checking the output of your spider is to use the
 of the spider at the method level. It has the advantage of being flexible and
 simple to use, but does not allow debugging code inside a method.
 
+.. highlight:: none
+
+.. skip: start
+
 In order to see the item scraped from a specific url::
 
     $ scrapy parse --spider=myspider -c parse_item -d 2 <item_url>
@@ -84,6 +95,8 @@ using::
 
     $ scrapy parse --spider=myspider -d 3 'http://example.com/page1'
 
+.. skip: end
+
 
 Scrapy Shell
 ============
@@ -93,13 +106,17 @@ spider, it is of little help to check what happens inside a callback, besides
 showing the response received and the output. How to debug the situation when
 ``parse_details`` sometimes receives no item?
 
+.. 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 = response.meta.get('item', None)
+
+    def parse_details(self, response, item=None):
         if item:
             # populate more `item` fields
             return item
@@ -113,10 +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)
@@ -130,16 +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:
 
-    def parse_details(self, response):
-        item = response.meta.get('item', None)
+.. 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: http://www.w3schools.com/tags/tag_base.asp
+.. _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``.
 
+.. _Deploying your project: https://scrapyd.readthedocs.io/en/latest/deploy.html
 .. _Scrapyd: https://github.com/scrapy/scrapyd
-.. _Deploying your project: https://scrapyd.readthedocs.org/en/latest/deploy.html
-.. _Scrapy Cloud: http://scrapinghub.com/scrapy-cloud/
 .. _scrapyd-client: https://github.com/scrapy/scrapyd-client
-.. _shub: http://doc.scrapinghub.com/shub.html
-.. _scrapyd-deploy documentation: http://scrapyd.readthedocs.org/en/latest/deploy.html
-.. _Scrapy Cloud documentation: http://doc.scrapinghub.com/scrapy-cloud.html
-.. _Scrapinghub: http://scrapinghub.com/
+.. _scrapyd-deploy documentation: https://scrapyd.readthedocs.io/en/latest/deploy.html
+.. _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

@@ -0,0 +1,320 @@
+.. _topics-developer-tools:
+
+=================================================
+Using your browser's Developer Tools for scraping
+=================================================
+
+Here is a general guide on how to use your browser's Developer Tools
+to ease the scraping process. Today almost all browsers come with
+built in `Developer Tools`_ and although we will use Firefox in this
+guide, the concepts are applicable to any other browser.
+
+In this guide we'll introduce the basic tools to use from a browser's
+Developer Tools by scraping `quotes.toscrape.com`_.
+
+.. _topics-livedom:
+
+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,
+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
+  used in Scrapy (in the Developer Tools settings click `Disable JavaScript`)
+
+* Never use full XPath paths, use relative and clever ones based on attributes
+  (such as ``id``, ``class``, ``width``, etc) or any identifying features like
+  ``contains(@href, 'image')``.
+
+* Never include ``<tbody>`` elements in your XPath expressions unless you
+  really know what you're doing
+
+.. _topics-inspector:
+
+Inspecting a website
+====================
+
+By far the most handy feature of the Developer Tools is the `Inspector`
+feature, which allows you to inspect the underlying HTML code of
+any webpage. To demonstrate the Inspector, let's look at the
+`quotes.toscrape.com`_-site.
+
+On the site we have a total of ten quotes from various authors with specific
+tags, as well as the Top Ten Tags. Let's say we want to extract all the quotes
+on this page, without any meta-information about authors, tags, etc.
+
+Instead of viewing the whole source code for the page, we can simply right click
+on a quote and select ``Inspect Element (Q)``, which opens up the `Inspector`.
+In it you should see something like this:
+
+.. image:: _images/inspector_01.png
+   :width: 777
+   :height: 469
+   :alt: Firefox's Inspector-tool
+
+The interesting part for us is this:
+
+.. code-block:: html
+
+    <div class="quote" itemscope="" itemtype="http://schema.org/CreativeWork">
+      <span class="text" itemprop="text">(...)</span>
+      <span>(...)</span>
+      <div class="tags">(...)</div>
+    </div>
+
+If you hover over the first ``div`` directly above the ``span`` tag highlighted
+in the screenshot, you'll see that the corresponding section of the webpage gets
+highlighted as well. So now we have a section, but we can't find our quote text
+anywhere.
+
+The advantage of the `Inspector` is that it automatically expands and collapses
+sections and tags of a webpage, which greatly improves readability. You can
+expand and collapse a tag by clicking on the arrow in front of it or by double
+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 https://quotes.toscrape.com/ in a terminal:
+
+.. code-block:: none
+
+    $ 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('https://quotes.toscrape.com/', 'quotes.html')
+
+.. 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
+go down a desired path in the source code starting from ``html``. So let's
+see if we can refine our XPath a bit:
+
+If we check the `Inspector` again we'll see that directly beneath our
+expanded ``div`` tag we have nine identical ``div`` tags, each with the
+same attributes as our first. If we expand any of them, we'll see the same
+structure as with our first quote: Two ``span`` tags and one ``div`` tag. We can
+expand each ``span`` tag with the ``class="text"`` inside our ``div`` tags and
+see each quote:
+
+.. code-block:: html
+
+    <div class="quote" itemscope="" itemtype="http://schema.org/CreativeWork">
+      <span class="text" itemprop="text">
+        “The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”
+      </span>
+      <span>(...)</span>
+      <div class="tags">(...)</div>
+    </div>
+
+
+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`_:
+
+.. 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
+the number of the last ``div``, but this would have been unnecessarily
+complex and by simply constructing an XPath with ``has-class("text")``
+we were able to extract all quotes in one line.
+
+The `Inspector` has a lot of other helpful features, such as searching in the
+source code or directly scrolling to an element you selected. Let's demonstrate
+a use case:
+
+Say you want to find the ``Next`` button on the page. Type ``Next`` into the
+search bar on the top right of the `Inspector`. You should get two results.
+The first is a ``li`` tag with the ``class="next"``, the second the text
+of an ``a`` tag. Right click on the ``a`` tag and select ``Scroll into View``.
+If you hover over the tag, you'll see the button highlighted. From here
+we could easily create a :ref:`Link Extractor <topics-link-extractors>` to
+follow the pagination. On a simple site such as this, there may not be
+the need to find an element visually but the ``Scroll into View`` function
+can be quite useful on complex sites.
+
+Note that the search bar can also be used to search for and test CSS
+selectors. For example, you could search for ``span.text`` to find
+all quote texts. Instead of a full text search, this searches for
+exactly the ``span`` tag with the ``class="text"`` in the page.
+
+.. _topics-network-tool:
+
+The Network-tool
+================
+While scraping you may come across dynamic webpages where some parts
+of the page are loaded dynamically through multiple requests. While
+this can be quite tricky, the `Network`-tool in the Developer Tools
+greatly facilitates this task. To demonstrate the Network-tool, let's
+take a look at the page `quotes.toscrape.com/scroll`_.
+
+The page is quite similar to the basic `quotes.toscrape.com`_-page,
+but instead of the above-mentioned ``Next`` button, the page
+automatically loads new quotes when you scroll to the bottom. We
+could go ahead and try out different XPaths directly, but instead
+we'll check another quite useful command from the Scrapy shell:
+
+.. skip: next
+
+.. code-block:: none
+
+  $ scrapy shell "quotes.toscrape.com/scroll"
+  (...)
+  >>> view(response)
+
+A browser window should open with the webpage but with one
+crucial difference: Instead of the quotes we just see a greenish
+bar with the word ``Loading...``.
+
+.. image:: _images/network_01.png
+   :width: 777
+   :height: 296
+   :alt: Response from quotes.toscrape.com/scroll
+
+The ``view(response)`` command let's us view the response our
+shell or later our spider receives from the server. Here we see
+that some basic template is loaded which includes the title,
+the login-button and the footer, but the quotes are missing. This
+tells us that the quotes are being loaded from a different request
+than ``quotes.toscrape/scroll``.
+
+If you click on the ``Network`` tab, you will probably only see
+two entries. The first thing we do is enable persistent logs by
+clicking on ``Persist Logs``. If this option is disabled, the
+log is automatically cleared each time you navigate to a different
+page. Enabling this option is a good default, since it gives us
+control on when to clear the logs.
+
+If we reload the page now, you'll see the log get populated with six
+new requests.
+
+.. image:: _images/network_02.png
+   :width: 777
+   :height: 241
+   :alt: Network tab with persistent logs and requests
+
+Here we see every request that has been made when reloading the page
+and can inspect each request and its response. So let's find out
+where our quotes are coming from:
+
+First click on the request with the name ``scroll``. On the right
+you can now inspect the request. In ``Headers`` you'll find details
+about the request headers, such as the URL, the method, the IP-address,
+and so on. We'll ignore the other tabs and click directly on ``Response``.
+
+What you should see in the ``Preview`` pane is the rendered HTML-code,
+that is exactly what we saw when we called ``view(response)`` in the
+shell. Accordingly the ``type`` of the request in the log is ``html``.
+The other requests have types like ``css`` or ``js``, but what
+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
+``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.
+
+.. image:: _images/network_03.png
+   :width: 777
+   :height: 375
+   :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:
+
+.. code-block:: python
+
+    import scrapy
+    import json
+
+
+    class QuoteSpider(scrapy.Spider):
+        name = "quote"
+        allowed_domains = ["quotes.toscrape.com"]
+        page = 1
+        start_urls = ["https://quotes.toscrape.com/api/quotes?page=1"]
+
+        def parse(self, response):
+            data = json.loads(response.text)
+            for quote in data["quotes"]:
+                yield {"quote": quote["text"]}
+            if data["has_next"]:
+                self.page += 1
+                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
+response, we parse the ``response.text`` and assign it to ``data``.
+This lets us operate on the JSON-object like on a Python dictionary.
+We iterate through the ``quotes`` and print out the ``quote["text"]``.
+If the handy ``has_next`` element is ``true`` (try loading
+`quotes.toscrape.com/api/quotes?page=10`_ in your browser or a
+page-number greater than 10), we increment the ``page`` attribute
+and ``yield`` a new request, inserting the incremented page-number
+into our ``url``.
+
+.. _requests-from-curl:
+
+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.Request.from_curl()` method to generate an equivalent
+request:
+
+.. code-block:: python
+
+    from scrapy import Request
+
+    request = Request.from_curl(
+        "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'"
+    )
+
+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`
+function to get a dictionary with the equivalent arguments:
+
+.. autofunction:: scrapy.utils.curl.curl_to_request_kwargs
+
+Note that to translate a cURL command into a Scrapy request,
+you may use `curl2scrapy <https://michael-shub.github.io/curl2scrapy/>`_.
+
+As you can see, with a few inspections in the `Network`-tool we
+were able to easily replicate the dynamic requests of the scrolling
+functionality of the page. Crawling dynamic pages can be quite
+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: 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/djangoitem.rst

@@ -10,4 +10,4 @@ DjangoItem has been moved into a separate project.
 
 It is hosted at:
 
-    https://github.com/scrapy/scrapy-djangoitem
+    https://github.com/scrapy-plugins/scrapy-djangoitem

docs/topics/dynamic-content.rst

@@ -0,0 +1,304 @@
+.. _topics-dynamic-content:
+
+====================================
+Selecting dynamically-loaded content
+====================================
+
+Some webpages show the desired data when you load them in a web browser.
+However, when you download them using Scrapy, you cannot reach the desired data
+using :ref:`selectors <topics-selectors>`.
+
+When this happens, the recommended approach is to
+:ref:`find the data source <topics-finding-data-source>` and extract the data
+from it.
+
+If you fail to do that, and you can nonetheless access the desired data through
+the :ref:`DOM <topics-livedom>` from your web browser, see
+:ref:`topics-javascript-rendering`.
+
+.. _topics-finding-data-source:
+
+Finding the data source
+=======================
+
+To extract the desired data, you must first find its source location.
+
+If the data is in a non-text-based format, such as an image or a PDF document,
+use the :ref:`network tool <topics-network-tool>` of your web browser to find
+the corresponding request, and :ref:`reproduce it
+<topics-reproducing-requests>`.
+
+If your web browser lets you select the desired data as text, the data may be
+defined in embedded JavaScript code, or loaded from an external resource in a
+text-based format.
+
+In that case, you can use a tool like wgrep_ to find the URL of that resource.
+
+If the data turns out to come from the original URL itself, you must
+:ref:`inspect the source code of the webpage <topics-inspecting-source>` to
+determine where the data is located.
+
+If the data comes from a different URL, you will need to :ref:`reproduce the
+corresponding request <topics-reproducing-requests>`.
+
+.. _topics-inspecting-source:
+
+Inspecting the source code of a webpage
+=======================================
+
+Sometimes you need to inspect the source code of a webpage (not the
+:ref:`DOM <topics-livedom>`) to determine where some desired data is located.
+
+Use Scrapy’s :command:`fetch` command to download the webpage contents as seen
+by Scrapy::
+
+    scrapy fetch --nolog https://example.com > response.html
+
+If the desired data is in embedded JavaScript code within a ``<script/>``
+element, see :ref:`topics-parsing-javascript`.
+
+If you cannot find the desired data, first make sure it’s not just Scrapy:
+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.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.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
+:ref:`topics-reproducing-requests`.
+
+.. _topics-reproducing-requests:
+
+Reproducing requests
+====================
+
+Sometimes we need to reproduce a request the way our web browser performs it.
+
+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.Request` with the same HTTP
+method and URL. However, you may also need to reproduce the body, headers and
+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.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.
+
+Once you get the expected response, you can :ref:`extract the desired data from
+it <topics-handling-response-formats>`.
+
+You can reproduce any request with Scrapy. However, some times reproducing all
+necessary requests may not seem efficient in developer time. If that is your
+case, and crawling speed is not a major concern for you, you can alternatively
+consider :ref:`JavaScript pre-rendering <topics-javascript-rendering>`.
+
+If you get the expected response `sometimes`, but not always, the issue is
+probably not your request, but the target server. The target server might be
+buggy, overloaded, or :ref:`banning <bans>` some of your requests.
+
+Note that to translate a cURL command into a Scrapy request,
+you may use `curl2scrapy <https://michael-shub.github.io/curl2scrapy/>`_.
+
+.. _topics-handling-response-formats:
+
+Handling different response formats
+===================================
+
+Once you have a response with the desired data, how you extract the desired
+data from it depends on the type of response:
+
+-   If the response is HTML or XML, use :ref:`selectors
+    <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>`:
+
+    .. 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` and then
+    :ref:`use it <topics-selectors>` as usual:
+
+    .. 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`.
+
+-   If the response is CSS, use a :doc:`regular expression <library/re>` to
+    extract the desired data from
+    :attr:`response.text <scrapy.http.TextResponse.text>`.
+
+.. _topics-parsing-images:
+
+-   If the response is an image or another format based on images (e.g. PDF),
+    read the response as bytes from
+    :attr:`response.body <scrapy.http.TextResponse.body>` and use an OCR
+    solution to extract the desired data as text.
+
+    For example, you can use pytesseract_. To read a table from a PDF,
+    `tabula-py`_ may be a better choice.
+
+-   If the response is SVG, or HTML with embedded SVG containing the desired
+    data, you may be able to extract the desired data using
+    :ref:`selectors <topics-selectors>`, since SVG is based on XML.
+
+    Otherwise, you might need to convert the SVG code into a raster image, and
+    :ref:`handle that raster image <topics-parsing-images>`.
+
+.. _topics-parsing-javascript:
+
+Parsing JavaScript code
+=======================
+
+If the desired data is hardcoded in JavaScript, you first need to get the
+JavaScript code:
+
+-   If the JavaScript code is in a JavaScript file, simply read
+    :attr:`response.text <scrapy.http.TextResponse.text>`.
+
+-   If the JavaScript code is within a ``<script/>`` element of an HTML page,
+    use :ref:`selectors <topics-selectors>` to extract the text within that
+    ``<script/>`` element.
+
+Once you have a string with the JavaScript code, you can extract the desired
+data from it:
+
+-   You might be able to use a :doc:`regular expression <library/re>` to
+    extract the desired data in JSON format, which you can then parse with
+    :func:`json.loads`.
+
+    For example, if the JavaScript code contains a separate line like
+    ``var data = {"field": "value"};`` you can extract that data as follows:
+
+    .. 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`.
+
+    For example, if the JavaScript code contains
+    ``var data = {field: "value", secondField: "second value"};``
+    you can extract that data as follows:
+
+    .. 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>`.
+
+    For example, if the JavaScript code contains
+    ``var data = {field: "value"};`` you can extract that data as follows:
+
+    .. 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:
+
+Pre-rendering JavaScript
+========================
+
+On webpages that fetch data from additional requests, reproducing those
+requests that contain the desired data is the preferred approach. The effort is
+often worth the result: structured, complete data with minimum parsing time and
+network transfer.
+
+However, sometimes it can be really hard to reproduce certain requests. Or you
+may need something that no request can give you, such as a screenshot of a
+webpage as seen in a web browser.
+
+In these cases use the Splash_ JavaScript-rendering service, along with
+`scrapy-splash`_ for seamless integration.
+
+Splash returns as HTML the :ref:`DOM <topics-livedom>` of a webpage, so that
+you can parse it with :ref:`selectors <topics-selectors>`. It provides great
+flexibility through configuration_ or scripting_.
+
+If you need something beyond what Splash offers, such as interacting with the
+DOM on-the-fly from Python code instead of using a previously-written script,
+or handling multiple web browser windows, you might need to
+:ref:`use a headless browser <topics-headless-browsing>` instead.
+
+.. _configuration: https://splash.readthedocs.io/en/stable/api.html
+.. _scripting: https://splash.readthedocs.io/en/stable/scripting-tutorial.html
+
+.. _topics-headless-browsing:
+
+Using a headless browser
+========================
+
+A `headless browser`_ is a special web browser that provides an API for
+automation. By installing the :ref:`asyncio reactor <install-asyncio>`,
+it is possible to integrate ``asyncio``-based libraries which handle headless browsers.
+
+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
+.. _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
+.. _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-playwright: https://github.com/scrapy-plugins/scrapy-playwright
+.. _scrapy-splash: https://github.com/scrapy-plugins/scrapy-splash
+.. _tabula-py: https://github.com/chezou/tabula-py
+.. _wget: https://www.gnu.org/software/wget/
+.. _wgrep: https://github.com/stav/wgrep

docs/topics/email.rst

@@ -7,39 +7,52 @@ Sending e-mail
 .. module:: scrapy.mail
    :synopsis: Email sending facility
 
-Although Python makes sending e-mails relatively easy via the `smtplib`_
+Although Python makes sending e-mails relatively easy via the :mod:`smtplib`
 library, Scrapy provides its own facility for sending e-mails which is very
-easy to use and it's implemented using `Twisted non-blocking IO`_, to avoid
-interfering with the non-blocking IO of the crawler. It also provides a
-simple API for sending attachments and it's very easy to configure, with a few
-:ref:`settings <topics-email-settings>`.
-
-.. _smtplib: https://docs.python.org/2/library/smtplib.html
-.. _Twisted non-blocking IO: http://twistedmatrix.com/documents/current/core/howto/defer-intro.html
+easy to use and it's implemented using :doc:`Twisted non-blocking IO
+<twisted:core/howto/defer-intro>`, to avoid interfering with the non-blocking
+IO of the crawler. It also provides a simple API for sending attachments and
+it's very easy to configure, with a few :ref:`settings
+<topics-email-settings>`.
 
 Quick example
 =============
 
 There are two ways to instantiate the mail sender. You can instantiate it using
-the standard constructor::
+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
 ==========================
 
 MailSender is the preferred class to use for sending emails from Scrapy, as it
-uses `Twisted non-blocking IO`_, like the rest of the framework.
+uses :doc:`Twisted non-blocking IO <twisted:core/howto/defer-intro>`, like the
+rest of the framework.
 
 .. class:: MailSender(smtphost=None, mailfrom=None, smtpuser=None, smtppass=None, smtpport=None)
 
@@ -54,19 +67,19 @@ uses `Twisted non-blocking IO`_, like the rest of the framework.
     :param smtpuser: the SMTP user. If omitted, the :setting:`MAIL_USER`
       setting will be used. If not given, no SMTP authentication will be
       performed.
-    :type smtphost: str
+    :type smtphost: str or bytes
 
     :param smtppass: the SMTP pass for authentication.
-    :type smtppass: str
+    :type smtppass: str or bytes
 
     :param smtpport: the SMTP port to connect to
     :type smtpport: int
 
     :param smtptls: enforce using SMTP STARTTLS
-    :type smtptls: boolean
+    :type smtptls: bool
 
     :param smtpssl: enforce using a secure SSL connection
-    :type smtpssl: boolean
+    :type smtpssl: bool
 
     .. classmethod:: from_settings(settings)
 
@@ -76,18 +89,18 @@ uses `Twisted non-blocking IO`_, like the rest of the framework.
         :param settings: the e-mail recipients
         :type settings: :class:`scrapy.settings.Settings` object
 
-    .. method:: send(to, subject, body, cc=None, attachs=(), mimetype='text/plain')
+    .. method:: send(to, subject, body, cc=None, attachs=(), mimetype='text/plain', charset=None)
 
         Send email to the given recipients.
 
-        :param to: the e-mail recipients
-        :type to: list
+        :param to: the e-mail recipients as a string or as a list of strings
+        :type to: str or list
 
         :param subject: the subject of the e-mail
         :type subject: str
 
-        :param cc: the e-mails to CC
-        :type cc: list
+        :param cc: the e-mails to CC as a string or as a list of strings
+        :type cc: str or list
 
         :param body: the e-mail body
         :type body: str
@@ -97,18 +110,21 @@ uses `Twisted non-blocking IO`_, like the rest of the framework.
           appear on the e-mail's attachment, ``mimetype`` is the mimetype of the
           attachment and ``file_object`` is a readable file object with the
           contents of the attachment
-        :type attachs: iterable
+        :type attachs: collections.abc.Iterable
 
         :param mimetype: the MIME type of the e-mail
         :type mimetype: str
 
+        :param charset: the character encoding to use for the e-mail contents
+        :type charset: str
+
 
 .. _topics-email-settings:
 
 Mail settings
 =============
 
-These settings define the default constructor values of the :class:`MailSender`
+These settings define the default ``__init__`` method values of the :class:`MailSender`
 class, and can be used to configure e-mail notifications in your project without
 writing any code (for those extensions and code that uses :class:`MailSender`).
 
@@ -161,7 +177,7 @@ Password to use for SMTP authentication, along with :setting:`MAIL_USER`.
 .. setting:: MAIL_TLS
 
 MAIL_TLS
----------
+--------
 
 Default: ``False``
 
@@ -170,7 +186,7 @@ Enforce using STARTTLS. STARTTLS is a way to take an existing insecure connectio
 .. setting:: MAIL_SSL
 
 MAIL_SSL
----------
+--------
 
 Default: ``False``
 

docs/topics/exceptions.rst

@@ -14,13 +14,6 @@ Built-in Exceptions reference
 
 Here's a list of all exceptions included in Scrapy and their usage.
 
-DropItem
---------
-
-.. exception:: DropItem
-
-The exception that must be raised by item pipeline stages to stop processing an
-Item. For more information see :ref:`topics-item-pipeline`.
 
 CloseSpider
 -----------
@@ -33,11 +26,29 @@ 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
+---------------
+
+.. exception:: DontCloseSpider
+
+This exception can be raised in a :signal:`spider_idle` signal handler to
+prevent the spider from being closed.
+
+DropItem
+--------
+
+.. exception:: DropItem
+
+The exception that must be raised by item pipeline stages to stop processing an
+Item. For more information see :ref:`topics-item-pipeline`.
 
 IgnoreRequest
 -------------
@@ -55,12 +66,12 @@ 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 constructor.
+The exception must be raised in the component's ``__init__`` method.
 
 NotSupported
 ------------
@@ -69,3 +80,38 @@ NotSupported
 
 This exception is raised to indicate an unsupported feature.
 
+StopDownload
+-------------
+
+.. versionadded:: 2.2
+
+.. exception:: StopDownload(fail=True)
+
+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:
+
+* If ``fail=True`` (default), the request errback is called. The response object is
+  available as the ``response`` attribute of the ``StopDownload`` exception,
+  which is in turn stored as the ``value`` attribute of the received
+  :class:`~twisted.python.failure.Failure` object. This means that in an errback
+  defined as ``def errback(self, failure)``, the response can be accessed though
+  ``failure.value.response``.
+
+* If ``fail=False``, the request callback is called instead.
+
+In both cases, the response could have its body truncated: the body contains
+all bytes received up until the exception is raised, including the bytes
+received in the signal handler that raises the exception. Also, the response
+object is marked with ``"download_stopped"`` in its :attr:`Response.flags`
+attribute.
+
+.. note:: ``fail`` is a keyword-only parameter, i.e. raising
+    ``StopDownload(False)`` or ``StopDownload(True)`` will raise
+    a :class:`TypeError`.
+
+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

@@ -36,38 +36,41 @@ to export
 3. and finally call the :meth:`~BaseItemExporter.finish_exporting` to signal
 the end of the exporting process
 
-Here you can see an :doc:`Item Pipeline <item-pipeline>` which uses an Item
-Exporter to export scraped items to different files, one per spider::
+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:
 
-   from scrapy import signals
-   from scrapy.exporters import XmlItemExporter
+.. code-block:: python
 
-   class XmlExportPipeline(object):
+    from itemadapter import ItemAdapter
+    from scrapy.exporters import XmlItemExporter
 
-       def __init__(self):
-           self.files = {}
 
-        @classmethod
-        def from_crawler(cls, crawler):
-            pipeline = cls()
-            crawler.signals.connect(pipeline.spider_opened, signals.spider_opened)
-            crawler.signals.connect(pipeline.spider_closed, signals.spider_closed)
-            return pipeline
+    class PerYearXmlExportPipeline:
+        """Distribute items across multiple XML files according to their 'year' field"""
 
-       def spider_opened(self, spider):
-           file = open('%s_products.xml' % spider.name, 'w+b')
-           self.files[spider] = file
-           self.exporter = XmlItemExporter(file)
-           self.exporter.start_exporting()
+        def open_spider(self, spider):
+            self.year_to_exporter = {}
 
-       def spider_closed(self, spider):
-           self.exporter.finish_exporting()
-           file = self.files.pop(spider)
-           file.close()
+        def close_spider(self, spider):
+            for exporter, xml_file in self.year_to_exporter.values():
+                exporter.finish_exporting()
+                xml_file.close()
 
-       def process_item(self, item, spider):
-           self.exporter.export_item(item)
-           return item
+        def _exporter_for_item(self, item):
+            adapter = ItemAdapter(item)
+            year = adapter["year"]
+            if year not in self.year_to_exporter:
+                xml_file = open(f"{year}.xml", "wb")
+                exporter = XmlItemExporter(xml_file)
+                exporter.start_exporting()
+                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)
+            exporter.export_item(item)
+            return item
 
 
 .. _topics-exporters-field-serialization:
@@ -90,16 +93,20 @@ described next.
 1. Declaring a serializer in the field
 --------------------------------------
 
-If you use :class:`~.Item` you can declare a serializer in the 
-:ref:`field metadata <topics-items-fields>`. The serializer must be 
+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 '$ %s' % str(value)
+        return f"$ {str(value)}"
+
 
     class Product(scrapy.Item):
         name = scrapy.Field()
@@ -115,16 +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 '$ %s' % 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:
 
@@ -132,24 +141,30 @@ 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
 ----------------
 
-.. class:: BaseItemExporter(fields_to_export=None, export_empty_fields=False, encoding='utf-8')
+.. class:: BaseItemExporter(fields_to_export=None, export_empty_fields=False, encoding='utf-8', indent=0, dont_fail=False)
 
    This is the (abstract) base class for all Item Exporters. It provides
    support for common features used by all (concrete) Item Exporters, such as
    defining what fields to export, whether to export empty fields, or which
    encoding to use.
 
-   These features can be configured through the constructor arguments which
+   These features can be configured through the ``__init__`` method arguments which
    populate their respective instance attributes: :attr:`fields_to_export`,
-   :attr:`export_empty_fields`, :attr:`encoding`.
+   :attr:`export_empty_fields`, :attr:`encoding`, :attr:`indent`.
+
+   .. versionadded:: 2.0
+      The *dont_fail* parameter.
 
    .. method:: export_item(item)
 
@@ -164,12 +179,12 @@ BaseItemExporter
       By default, this method looks for a serializer :ref:`declared in the item
       field <topics-exporters-serializers>` and returns the result of applying
       that serializer to the value. If no serializer is found, it returns the
-      value unchanged except for ``unicode`` values which are encoded to
-      ``str`` using the encoding declared in the :attr:`encoding` attribute.
+      value unchanged.
 
-      :param field: the field being serialized. If a raw dict is being 
-          exported (not :class:`~.Item`) *field* value is an empty dict.
-      :type field: :class:`~scrapy.item.Field` object or an empty dict 
+      :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.Field` object or a :class:`dict` instance
 
       :param name: the name of the field being serialized
       :type name: str
@@ -192,14 +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:
 
-      Some exporters may require fields_to_export list in order to export the
-      data properly when spiders return dicts (not :class:`~Item` instances).
+      -   ``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
 
@@ -211,21 +237,34 @@ BaseItemExporter
 
    .. attribute:: encoding
 
-      The encoding that will be used to encode unicode values. This only
-      affects unicode values (which are always serialized to str using this
-      encoding). Other value types are passed unchanged to the specific
-      serialization library.
+      The output character encoding.
+
+   .. attribute:: indent
+
+      Amount of spaces used to indent the output on each level. Defaults to ``0``.
+
+      * ``indent=None`` selects the most compact representation,
+        all items in the same line with no indentation
+      * ``indent<=0`` each item on its own line, no indentation
+      * ``indent>0`` each item on its own line, indented with the provided numeric value
+
+PythonItemExporter
+------------------
+
+.. autoclass:: PythonItemExporter
+
 
 .. highlight:: none
 
 XmlItemExporter
 ---------------
 
-.. class:: XmlItemExporter(file, item_element='item', root_element='items', \**kwargs)
+.. class:: XmlItemExporter(file, item_element='item', root_element='items', **kwargs)
 
-   Exports Items in XML format to the specified file object.
+   Exports items in XML format to the specified file object.
 
-   :param file: the file-like object to use for exporting the data.
+   :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)
 
    :param root_element: The name of root element in the exported XML.
    :type root_element: str
@@ -233,8 +272,8 @@ XmlItemExporter
    :param item_element: The name of each item element in the exported XML.
    :type item_element: str
 
-   The additional keyword arguments of this constructor are passed to the
-   :class:`BaseItemExporter` constructor.
+   The additional keyword arguments of this ``__init__`` method are passed to the
+   :class:`BaseItemExporter` ``__init__`` method.
 
    A typical output of this exporter would be::
 
@@ -274,27 +313,33 @@ XmlItemExporter
 CsvItemExporter
 ---------------
 
-.. class:: CsvItemExporter(file, include_headers_line=True, join_multivalued=',', \**kwargs)
+.. class:: CsvItemExporter(file, include_headers_line=True, join_multivalued=',', errors=None, **kwargs)
 
-   Exports Items in CSV format to the given file-like object. If the
+   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.
+   :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)
 
    :param include_headers_line: If enabled, makes the exporter output a header
       line with the field names taken from
       :attr:`BaseItemExporter.fields_to_export` or the first exported item fields.
-   :type include_headers_line: boolean
+   :type include_headers_line: bool
 
    :param join_multivalued: The char (or chars) that will be used for joining
       multi-valued fields, if found.
    :type include_headers_line: str
 
-   The additional keyword arguments of this constructor are passed to the
-   :class:`BaseItemExporter` constructor, and the leftover arguments to the
-   `csv.writer`_ constructor, so you can use any `csv.writer` constructor
+   :param errors: The optional string that specifies how encoding and decoding
+      errors are to be handled. For more information see
+      :class:`io.TextIOWrapper`.
+   :type errors: str
+
+   The additional keyword arguments of this ``__init__`` method are passed to the
+   :class:`BaseItemExporter` ``__init__`` method, and the leftover arguments to the
+   :func:`csv.writer` function, so you can use any :func:`csv.writer` function
    argument to customize this exporter.
 
    A typical output of this exporter would be::
@@ -303,40 +348,38 @@ CsvItemExporter
       Color TV,1200
       DVD player,200
 
-.. _csv.writer: https://docs.python.org/2/library/csv.html#csv.writer
-
 PickleItemExporter
 ------------------
 
-.. class:: PickleItemExporter(file, protocol=0, \**kwargs)
+.. class:: PickleItemExporter(file, protocol=0, **kwargs)
 
-   Exports Items in pickle format to the given file-like object.
+   Exports items in pickle format to the given file-like object.
 
-   :param file: the file-like object to use for exporting the data.
+   :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)
 
    :param protocol: The pickle protocol to use.
    :type protocol: int
 
-   For more information, refer to the `pickle module documentation`_.
+   For more information, see :mod:`pickle`.
 
-   The additional keyword arguments of this constructor are passed to the
-   :class:`BaseItemExporter` constructor.
+   The additional keyword arguments of this ``__init__`` method are passed to the
+   :class:`BaseItemExporter` ``__init__`` method.
 
    Pickle isn't a human readable format, so no output examples are provided.
 
-.. _pickle module documentation: https://docs.python.org/2/library/pickle.html
-
 PprintItemExporter
 ------------------
 
-.. class:: PprintItemExporter(file, \**kwargs)
+.. class:: PprintItemExporter(file, **kwargs)
 
-   Exports Items in pretty print format to the specified file object.
+   Exports items in pretty print format to the specified file object.
 
-   :param file: the file-like object to use for exporting the data.
+   :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)
 
-   The additional keyword arguments of this constructor are passed to the
-   :class:`BaseItemExporter` constructor.
+   The additional keyword arguments of this ``__init__`` method are passed to the
+   :class:`BaseItemExporter` ``__init__`` method.
 
    A typical output of this exporter would be::
 
@@ -348,15 +391,16 @@ PprintItemExporter
 JsonItemExporter
 ----------------
 
-.. class:: JsonItemExporter(file, \**kwargs)
+.. class:: JsonItemExporter(file, **kwargs)
 
-   Exports Items in JSON format to the specified file-like object, writing all
-   objects as a list of objects. The additional constructor arguments are
-   passed to the :class:`BaseItemExporter` constructor, and the leftover
-   arguments to the `JSONEncoder`_ constructor, so you can use any
-   `JSONEncoder`_ constructor argument to customize this exporter.
+   Exports items in JSON format to the specified file-like object, writing all
+   objects as a list of objects. The additional ``__init__`` method arguments are
+   passed to the :class:`BaseItemExporter` ``__init__`` method, and the leftover
+   arguments to the :class:`~json.JSONEncoder` ``__init__`` method, so you can use any
+   :class:`~json.JSONEncoder` ``__init__`` method argument to customize this exporter.
 
-   :param file: the file-like object to use for exporting the data.
+   :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)
 
    A typical output of this exporter would be::
 
@@ -373,20 +417,19 @@ JsonItemExporter
       stream-friendly format, consider using :class:`JsonLinesItemExporter`
       instead, or splitting the output in multiple chunks.
 
-.. _JSONEncoder: https://docs.python.org/2/library/json.html#json.JSONEncoder
-
 JsonLinesItemExporter
 ---------------------
 
-.. class:: JsonLinesItemExporter(file, \**kwargs)
+.. class:: JsonLinesItemExporter(file, **kwargs)
 
-   Exports Items in JSON format to the specified file-like object, writing one
-   JSON-encoded item per line. The additional constructor arguments are passed
-   to the :class:`BaseItemExporter` constructor, and the leftover arguments to
-   the `JSONEncoder`_ constructor, so you can use any `JSONEncoder`_
-   constructor argument to customize this exporter.
+   Exports items in JSON format to the specified file-like object, writing one
+   JSON-encoded item per line. The additional ``__init__`` method arguments are passed
+   to the :class:`BaseItemExporter` ``__init__`` method, and the leftover arguments to
+   the :class:`~json.JSONEncoder` ``__init__`` method, so you can use any
+   :class:`~json.JSONEncoder` ``__init__`` method argument to customize this exporter.
 
-   :param file: the file-like object to use for exporting the data.
+   :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)
 
    A typical output of this exporter would be::
 
@@ -396,4 +439,7 @@ JsonLinesItemExporter
    Unlike the one produced by :class:`JsonItemExporter`, the format produced by
    this exporter is well suited for serializing large amounts of data.
 
-.. _JSONEncoder: https://docs.python.org/2/library/json.html#json.JSONEncoder
+MarshalItemExporter
+-------------------
+
+.. autoclass:: MarshalItemExporter

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
 ==================
@@ -17,26 +16,28 @@ Extensions use the :ref:`Scrapy settings <topics-settings>` to manage their
 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, an
-hypothetic extension to handle `Google Sitemaps`_ would use settings like
-`GOOGLESITEMAP_ENABLED`, `GOOGLESITEMAP_DEPTH`, and so on.
+avoid collision with existing (and future) extensions. For example, a
+hypothetical extension to handle `Google Sitemaps`_ would use settings like
+``GOOGLESITEMAP_ENABLED``, ``GOOGLESITEMAP_DEPTH``, and so on.
 
-.. _Google Sitemaps: http://en.wikipedia.org/wiki/Sitemaps
+.. _Google Sitemaps: https://en.wikipedia.org/wiki/Sitemaps
 
 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 constructor (``__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,
     }
 
 
@@ -63,12 +64,14 @@ but disabled unless the :setting:`HTTPCACHE_ENABLED` setting is set.
 Disabling an extension
 ======================
 
-In order to disable an extension that comes enabled by default (ie. those
+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(object):
 
+    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)
@@ -144,7 +149,7 @@ Here is the code of such extension::
             self.items_scraped += 1
             if self.items_scraped % self.item_count == 0:
                 logger.info("scraped %d items", self.items_scraped)
-                
+
 
 .. _topics-extensions-ref:
 
@@ -220,7 +225,6 @@ can be configured with the following settings:
 * :setting:`MEMUSAGE_LIMIT_MB`
 * :setting:`MEMUSAGE_WARNING_MB`
 * :setting:`MEMUSAGE_NOTIFY_MAIL`
-* :setting:`MEMUSAGE_REPORT`
 * :setting:`MEMUSAGE_CHECK_INTERVAL_SECONDS`
 
 Memory debugger extension
@@ -258,6 +262,12 @@ settings:
 * :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
@@ -278,17 +288,15 @@ CLOSESPIDER_ITEMCOUNT
 Default: ``0``
 
 An integer which specifies a number of items. If the spider scrapes more than
-that amount if items and those items are passed by the item pipeline, the
-spider will be closed with the reason ``closespider_itemcount``. If zero (or
-non set), spiders won't be closed by number of passed items.
+that amount and those items are passed by the item pipeline, the
+spider will be closed with the reason ``closespider_itemcount``.
+If zero (or non set), spiders won't be closed by number of passed items.
 
 .. setting:: CLOSESPIDER_PAGECOUNT
 
 CLOSESPIDER_PAGECOUNT
 """""""""""""""""""""
 
-.. versionadded:: 0.11
-
 Default: ``0``
 
 An integer which specifies the maximum number of responses to crawl. If the spider
@@ -301,8 +309,6 @@ number of crawled responses.
 CLOSESPIDER_ERRORCOUNT
 """"""""""""""""""""""
 
-.. versionadded:: 0.11
-
 Default: ``0``
 
 An integer which specifies the maximum number of errors to receive before
@@ -323,6 +329,11 @@ 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
 
@@ -344,7 +355,7 @@ signal is received. The information dumped is the following:
 After the stack trace and engine status is dumped, the Scrapy process continues
 running normally.
 
-This extension only works on POSIX-compliant platforms (ie. not Windows),
+This extension only works on POSIX-compliant platforms (i.e. not Windows),
 because the `SIGQUIT`_ and `SIGUSR2`_ signals are not available on Windows.
 
 There are at least two ways to send Scrapy the `SIGQUIT`_ signal:
@@ -355,21 +366,20 @@ There are at least two ways to send Scrapy the `SIGQUIT`_ signal:
 
     kill -QUIT <pid>
 
-.. _SIGUSR2: http://en.wikipedia.org/wiki/SIGUSR1_and_SIGUSR2
-.. _SIGQUIT: http://en.wikipedia.org/wiki/SIGQUIT
+.. _SIGUSR2: https://en.wikipedia.org/wiki/SIGUSR1_and_SIGUSR2
+.. _SIGQUIT: https://en.wikipedia.org/wiki/SIGQUIT
 
 Debugger extension
 ~~~~~~~~~~~~~~~~~~
 
 .. class:: Debugger
 
-Invokes a `Python debugger`_ inside a running Scrapy process when a `SIGUSR2`_
+Invokes a :doc:`Python debugger <library/pdb>` inside a running Scrapy process when a `SIGUSR2`_
 signal is received. After the debugger is exited, the Scrapy process continues
 running normally.
 
-For more info see `Debugging in Python`.
+For more info see `Debugging in Python`_.
 
-This extension only works on POSIX-compliant platforms (ie. not Windows).
+This extension only works on POSIX-compliant platforms (i.e. not Windows).
 
-.. _Python debugger: https://docs.python.org/2/library/pdb.html
-.. _Debugging in Python: http://www.ferg.org/papers/debugging_in_python.html
+.. _Debugging in Python: https://pythonconquerstheuniverse.wordpress.com/2009/09/10/debugging-in-python/

docs/topics/feed-exports.rst

@@ -4,15 +4,13 @@
 Feed exports
 ============
 
-.. versionadded:: 0.10
-
 One of the most frequently required features when implementing scrapers is
 being able to store the scraped data properly and, quite often, that means
 generating an "export file" with the scraped data (commonly called "export
 feed") to be consumed by other systems.
 
 Scrapy provides this functionality out of the box with the Feed Exports, which
-allows you to generate a feed with the scraped items, using multiple
+allows you to generate feeds with the scraped items, using multiple
 serialization formats and storage backends.
 
 .. _topics-feed-format:
@@ -23,10 +21,10 @@ 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.
@@ -36,54 +34,58 @@ But you can also extend the supported format through the
 JSON
 ----
 
- * :setting:`FEED_FORMAT`: ``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
 ----------
 
- * :setting:`FEED_FORMAT`: ``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
 ---
 
- * :setting:`FEED_FORMAT`: ``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
 ---
 
- * :setting:`FEED_FORMAT`: ``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
 ------
 
- * :setting:`FEED_FORMAT`: ``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
 -------
 
- * :setting:`FEED_FORMAT`: ``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:
@@ -91,19 +93,20 @@ Marshal
 Storages
 ========
 
-When using the feed exports you define where to store the feed using a URI_
-(through the :setting:`FEED_URI` setting). The feed exports supports multiple
+When using the feed exports you define where to store the feed using one or multiple URIs_
+(through the :setting:`FEEDS` setting). The feed exports supports multiple
 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 boto_)
- * :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 boto_
+not available. For example, the S3 backend is only available if the boto3_
 library is installed.
 
 
@@ -115,8 +118,8 @@ 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``
@@ -124,13 +127,16 @@ 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:
@@ -145,9 +151,9 @@ 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
@@ -160,9 +166,23 @@ 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>`.
+
 
 .. _topics-feed-storage-s3:
 
@@ -171,19 +191,73 @@ 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: `boto`_
+    -   ``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`_)
+
+.. _temporary security credentials: https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#temporary-access-keys
+
+You can also define a custom ACL and custom endpoint for exported feeds using this setting:
+
+-   :setting:`FEED_STORAGE_S3_ACL`
+-   :setting:`AWS_ENDPOINT_URL`
+
+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>`.
+
+
+.. _topics-feed-storage-gcs:
+
+Google Cloud Storage (GCS)
+--------------------------
+
+.. versionadded:: 2.3
+
+The feeds are stored on `Google Cloud Storage`_.
+
+-   URI scheme: ``gs``
+
+-   Example URIs:
+
+    -   ``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`
+
+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>`.
+
+.. _google-cloud-storage: https://cloud.google.com/storage/docs/reference/libraries#client-libraries-install-python
+
 
 .. _topics-feed-storage-stdout:
 
@@ -192,9 +266,127 @@ 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:
+
+Delayed file delivery
+---------------------
+
+As indicated above, some of the described storage backends use delayed file
+delivery.
+
+These storage backends do not upload items to the feed URI as those items are
+scraped. Instead, Scrapy writes items into a temporary local file, and only
+once all the file contents have been written (i.e. at the end of the crawl) is
+that file uploaded to the feed URI.
+
+If you want item delivery to start earlier when using one of these storage
+backends, use :setting:`FEED_EXPORT_BATCH_ITEM_COUNT` to split the output items
+in multiple files, with the specified maximum item count per file. That way, as
+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
@@ -202,34 +394,151 @@ Settings
 
 These are the settings used for configuring the feed exports:
 
- * :setting:`FEED_URI` (mandatory)
- * :setting:`FEED_FORMAT`
- * :setting:`FEED_STORAGES`
- * :setting:`FEED_EXPORTERS`
- * :setting:`FEED_STORE_EMPTY`
- * :setting:`FEED_EXPORT_FIELDS`
+-   :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
 
-.. setting:: FEED_URI
+.. setting:: FEEDS
 
-FEED_URI
---------
+FEEDS
+-----
+
+.. versionadded:: 2.1
+
+Default: ``{}``
+
+A dictionary in which every key is a feed URI (or a :class:`pathlib.Path`
+object) and each value is a nested dictionary containing configuration
+parameters for the specific feed.
+
+This setting is required for enabling the feed export feature.
+
+See :ref:`topics-feed-storage-backends` for supported URI schemes.
+
+For instance::
+
+    {
+        'items.json': {
+            '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.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:
+
+-   ``format``: the :ref:`serialization format <topics-feed-format>`.
+
+    This setting is mandatory, there is no fallback value.
+
+-   ``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``).
+
+    The default value depends on the :ref:`storage backend
+    <topics-feed-storage-backends>`:
+
+    -   :ref:`topics-feed-storage-fs`: ``False``
+
+    -   :ref:`topics-feed-storage-ftp`: ``True``
+
+        .. note:: Some FTP servers may not support appending to files (the
+                  ``APPE`` FTP command).
+
+    -   :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
+
+FEED_EXPORT_ENCODING
+--------------------
 
 Default: ``None``
 
-The URI of the export feed. See :ref:`topics-feed-storage-backends` for
-supported URI schemes.
+The encoding to be used for the feed.
 
-This setting is required for enabling the feed exports.
+If unset or set to ``None`` (default) it uses UTF-8 for everything except JSON output,
+which uses safe numeric encoding (``\uXXXX`` sequences) for historic reasons.
 
-.. setting:: FEED_FORMAT
+Use ``utf-8`` if you want UTF-8 for JSON too.
 
-FEED_FORMAT
------------
-
-The serialization format to be used for the feed. See
-:ref:`topics-feed-format` for possible values.
+.. versionchanged:: 2.8
+   The :command:`startproject` command now sets this setting to
+   ``utf-8`` in the generated ``settings.py`` file.
 
 .. setting:: FEED_EXPORT_FIELDS
 
@@ -238,18 +547,25 @@ FEED_EXPORT_FIELDS
 
 Default: ``None``
 
-A list of fields to export, optional.
-Example: ``FEED_EXPORT_FIELDS = ["foo", "bar", "baz"]``.
+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.
 
-Use FEED_EXPORT_FIELDS option to define fields to export and their order.
+.. setting:: FEED_EXPORT_INDENT
 
-When FEED_EXPORT_FIELDS is empty or None (default), Scrapy uses fields
-defined in dicts or :class:`~.Item` subclasses a spider is yielding.
+FEED_EXPORT_INDENT
+------------------
 
-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.
+Default: ``0``
+
+Amount of spaces used to indent the output on each level. If ``FEED_EXPORT_INDENT``
+is a non-negative integer, then array elements and object members will be pretty-printed
+with that indent level. An indent level of ``0`` (the default), or negative,
+will put each item on a new line. ``None`` selects the most compact representation.
+
+Currently implemented only by :class:`~scrapy.exporters.JsonItemExporter`
+and :class:`~scrapy.exporters.XmlItemExporter`, i.e. when you are exporting
+to ``.json`` or ``.xml``.
 
 .. setting:: FEED_STORE_EMPTY
 
@@ -258,40 +574,68 @@ FEED_STORE_EMPTY
 
 Default: ``False``
 
-Whether to export empty feeds (ie. feeds with no items).
+Whether to export empty feeds (i.e. feeds with no items).
 
 .. setting:: FEED_STORAGES
 
 FEED_STORAGES
 -------------
 
-Default:: ``{}``
+Default: ``{}``
 
 A dict containing additional feed storage backends supported by your project.
 The keys are URI schemes and the values are paths to storage classes.
 
+.. setting:: FEED_STORAGE_FTP_ACTIVE
+
+FEED_STORAGE_FTP_ACTIVE
+-----------------------
+
+Default: ``False``
+
+Whether to use the active connection mode when exporting feeds to an FTP server
+(``True``) or use the passive connection mode instead (``False``, default).
+
+For information about FTP connection modes, see `What is the difference between
+active and passive FTP? <https://stackoverflow.com/a/1699163>`_.
+
+.. setting:: FEED_STORAGE_S3_ACL
+
+FEED_STORAGE_S3_ACL
+-------------------
+
+Default: ``''`` (empty string)
+
+A string containing a custom ACL for feeds exported to Amazon S3 by your project.
+
+For a complete list of available values, access the `Canned ACL`_ section on Amazon S3 docs.
+
 .. setting:: FEED_STORAGES_BASE
 
 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
@@ -299,7 +643,7 @@ can disable any of these backends by assigning ``None`` to their URI scheme in
 FEED_EXPORTERS
 --------------
 
-Default:: ``{}``
+Default: ``{}``
 
 A dict containing additional exporters supported by your project. The keys are
 serialization formats and the values are paths to :ref:`Item exporter
@@ -309,27 +653,152 @@ 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,
     }
 
-.. _URI: http://en.wikipedia.org/wiki/Uniform_Resource_Identifier
-.. _Amazon S3: http://aws.amazon.com/s3/
-.. _boto: http://code.google.com/p/boto/
+
+.. setting:: FEED_EXPORT_BATCH_ITEM_COUNT
+
+FEED_EXPORT_BATCH_ITEM_COUNT
+----------------------------
+
+.. versionadded:: 2.3.0
+
+Default: ``0``
+
+If assigned an integer number higher than ``0``, Scrapy generates multiple output files
+storing up to the specified number of items in each output file.
+
+When generating multiple output files, you must use at least one of the following
+placeholders in the feed URI to indicate how the different output file names are
+generated:
+
+* ``%(batch_time)s`` - gets replaced by a timestamp when the feed is being created
+  (e.g. ``2020-03-28T14-45-08.237134``)
+
+* ``%(batch_id)d`` - gets replaced by the 1-based sequence number of the batch.
+
+  Use :ref:`printf-style string formatting <python:old-string-formatting>` to
+  alter the number format. For example, to make the batch ID a 5-digit
+  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:
+
+.. code-block:: python
+
+    FEED_EXPORT_BATCH_ITEM_COUNT = 100
+
+And your :command:`crawl` command line is::
+
+    scrapy crawl spidername -o "dirname/%(batch_id)d-filename%(batch_time)s.json"
+
+The command line above can generate a directory tree like::
+
+    ->projectname
+    -->dirname
+    --->1-filename2020-03-28T14-45-08.237134.json
+    --->2-filename2020-03-28T14-45-09.148903.json
+    --->3-filename2020-03-28T14-45-10.046092.json
+
+Where the first and second files contain exactly 100 items. The last one contains
+100 items or fewer.
+
+
+.. setting:: FEED_URI_PARAMS
+
+FEED_URI_PARAMS
+---------------
+
+Default: ``None``
+
+A string with the import path of a function to set the parameters to apply with
+:ref:`printf-style string formatting <python:old-string-formatting>` to the
+feed URI.
+
+The function signature should be as follows:
+
+.. function:: uri_params(params, spider)
+
+   Return a :class:`dict` of key-value pairs to apply to the feed URI using
+   :ref:`printf-style string formatting <python:old-string-formatting>`.
+
+   :param params: default key-value pairs
+
+        Specifically:
+
+        -   ``batch_id``: ID of the file batch. See
+            :setting:`FEED_EXPORT_BATCH_ITEM_COUNT`.
+
+            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.Spider
+
+   .. 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:
+
+    .. code-block:: python
+
+        # myproject/utils.py
+        def uri_params(params, spider):
+            return {**params, "spider_name": spider.name}
+
+#.  Point :setting:`FEED_URI_PARAMS` to that function in your settings:
+
+    .. code-block:: python
+
+        # myproject/settings.py
+        FEED_URI_PARAMS = "myproject.utils.uri_params"
+
+#.  Use ``%(spider_name)s`` in your feed URI::
+
+        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/
+.. _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/firebug.rst

@@ -1,167 +0,0 @@
-.. _topics-firebug:
-
-==========================
-Using Firebug for scraping
-==========================
-
-.. note:: Google Directory, the example website used in this guide is no longer
-   available as it `has been shut down by Google`_. The concepts in this guide
-   are still valid though. If you want to update this guide to use a new
-   (working) site, your contribution will be more than welcome!. See :ref:`topics-contributing`
-   for information on how to do so.
-
-Introduction
-============
-
-This document explains how to use `Firebug`_ (a Firefox add-on) to make the
-scraping process easier and more fun. For other useful Firefox add-ons see
-:ref:`topics-firefox-addons`. There are some caveats with using Firefox add-ons
-to inspect pages, see :ref:`topics-firefox-livedom`.
-
-In this example, we'll show how to use `Firebug`_ to scrape data from the
-`Google Directory`_, which contains the same data as the `Open Directory
-Project`_ used in the :ref:`tutorial <intro-tutorial>` but with a different
-face.
-
-.. _Firebug: http://getfirebug.com
-.. _Google Directory: http://directory.google.com/
-.. _Open Directory Project: http://www.dmoz.org
-
-Firebug comes with a very useful feature called `Inspect Element`_ which allows
-you to inspect the HTML code of the different page elements just by hovering
-your mouse over them. Otherwise you would have to search for the tags manually
-through the HTML body which can be a very tedious task.
-
-.. _Inspect Element: https://www.youtube.com/watch?v=-pT_pDe54aA
-
-In the following screenshot you can see the `Inspect Element`_ tool in action.
-
-.. image:: _images/firebug1.png
-   :width: 913
-   :height: 600
-   :alt: Inspecting elements with Firebug
-
-At first sight, we can see that the directory is divided in categories, which
-are also divided in subcategories.
-
-However, it seems that there are more subcategories than the ones being shown
-in this page, so we'll keep looking:
-
-.. image:: _images/firebug2.png
-   :width: 819
-   :height: 629
-   :alt: Inspecting elements with Firebug
-
-As expected, the subcategories contain links to other subcategories, and also
-links to actual websites, which is the purpose of the directory.
-
-Getting links to follow
-=======================
-
-By looking at the category URLs we can see they share a pattern:
-
-    http://directory.google.com/Category/Subcategory/Another_Subcategory
-
-Once we know that, we are able to construct a regular expression to follow
-those links. For example, the following one::
-
-    directory\.google\.com/[A-Z][a-zA-Z_/]+$
-
-So, based on that regular expression we can create the first crawling rule::
-
-    Rule(LinkExtractor(allow='directory.google.com/[A-Z][a-zA-Z_/]+$', ),
-        'parse_category',
-        follow=True,
-    ),
-
-The :class:`~scrapy.spiders.Rule` object instructs
-:class:`~scrapy.spiders.CrawlSpider` based spiders how to follow the
-category links. ``parse_category`` will be a method of the spider which will
-process and extract data from those pages.
-
-This is how the spider would look so far::
-
-   from scrapy.linkextractors import LinkExtractor
-   from scrapy.spiders import CrawlSpider, Rule
-
-   class GoogleDirectorySpider(CrawlSpider):
-       name = 'directory.google.com'
-       allowed_domains = ['directory.google.com']
-       start_urls = ['http://directory.google.com/']
-
-       rules = (
-           Rule(LinkExtractor(allow='directory\.google\.com/[A-Z][a-zA-Z_/]+$'),
-               'parse_category', follow=True,
-           ),
-       )
-
-       def parse_category(self, response):
-           # write the category page data extraction code here
-           pass
-
-
-Extracting the data
-===================
-
-Now we're going to write the code to extract data from those pages.
-
-With the help of Firebug, we'll take a look at some page containing links to
-websites (say http://directory.google.com/Top/Arts/Awards/) and find out how we can
-extract those links using :ref:`Selectors <topics-selectors>`. We'll also
-use the :ref:`Scrapy shell <topics-shell>` to test those XPath's and make sure
-they work as we expect.
-
-.. image:: _images/firebug3.png
-   :width: 965
-   :height: 751
-   :alt: Inspecting elements with Firebug
-
-As you can see, the page markup is not very descriptive: the elements don't
-contain ``id``, ``class`` or any attribute that clearly identifies them, so
-we'll use the ranking bars as a reference point to select the data to extract
-when we construct our XPaths.
-
-After using FireBug, we can see that each link is inside a ``td`` tag, which is
-itself inside a ``tr`` tag that also contains the link's ranking bar (in
-another ``td``).
-
-So we can select the ranking bar, then find its parent (the ``tr``), and then
-finally, the link's ``td`` (which contains the data we want to scrape).
-
-This results in the following XPath::
-
-    //td[descendant::a[contains(@href, "#pagerank")]]/following-sibling::td//a
-
-It's important to use the :ref:`Scrapy shell <topics-shell>` to test these
-complex XPath expressions and make sure they work as expected.
-
-Basically, that expression will look for the ranking bar's ``td`` element, and
-then select any ``td`` element who has a descendant ``a`` element whose
-``href`` attribute contains the string ``#pagerank``"
-
-Of course, this is not the only XPath, and maybe not the simpler one to select
-that data. Another approach could be, for example, to find any ``font`` tags
-that have that grey colour of the links,
-
-Finally, we can write our ``parse_category()`` method::
-
-    def parse_category(self, response):
-        # The path to website links in directory page
-        links = response.xpath('//td[descendant::a[contains(@href, "#pagerank")]]/following-sibling::td/font')
-
-        for link in links:
-            item = DirectoryItem()
-            item['name'] = link.xpath('a/text()').extract()
-            item['url'] = link.xpath('a/@href').extract()
-            item['description'] = link.xpath('font[2]/text()').extract()
-            yield item
-
-
-Be aware that you may find some elements which appear in Firebug but
-not in the original HTML, such as the typical case of ``<tbody>``
-elements.
-
-or tags which Therefer   in page HTML
-sources may on Firebug inspects the live DOM
-
-.. _has been shut down by Google: http://searchenginewatch.com/sew/news/2096661/google-directory-shut

docs/topics/firefox.rst

@@ -1,82 +0,0 @@
-.. _topics-firefox:
-
-==========================
-Using Firefox for scraping
-==========================
-
-Here is a list of tips and advice on using Firefox for scraping, along with a
-list of useful Firefox add-ons to ease the scraping process.
-
-.. _topics-firefox-livedom:
-
-Caveats with inspecting the live browser DOM
-============================================
-
-Since Firefox add-ons 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,
-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 when working with
-Firefox and XPath:
-
-* Disable Firefox Javascript while inspecting the DOM looking for XPaths to be
-  used in Scrapy
-
-* Never use full XPath paths, use relative and clever ones based on attributes
-  (such as ``id``, ``class``, ``width``, etc) or any identifying features like
-  ``contains(@href, 'image')``.
-
-* Never include ``<tbody>`` elements in your XPath expressions unless you
-  really know what you're doing
-
-.. _topics-firefox-addons:
-
-Useful Firefox add-ons for scraping
-===================================
-
-Firebug
--------
-
-`Firebug`_ is a widely known tool among web developers and it's also very
-useful for scraping. In particular, its `Inspect Element`_ feature comes very
-handy when you need to construct the XPaths for extracting data because it
-allows you to view the HTML code of each page element while moving your mouse
-over it.
-
-See :ref:`topics-firebug` for a detailed guide on how to use Firebug with
-Scrapy.
-
-XPather
--------
-
-`XPather`_ allows you to test XPath expressions directly on the pages.
-
-XPath Checker
--------------
-
-`XPath Checker`_ is another Firefox add-on for testing XPaths on your pages.
-
-Tamper Data
------------
-
-`Tamper Data`_ is a Firefox add-on which allows you to view and modify the HTTP
-request headers sent by Firefox. Firebug also allows to view HTTP headers, but
-not to modify them.
-
-Firecookie
-----------
-
-`Firecookie`_ makes it easier to view and manage cookies. You can use this
-extension to create a new cookie, delete existing cookies, see a list of cookies
-for the current site, manage cookies permissions and a lot more. 
-
-.. _Firebug: http://getfirebug.com
-.. _Inspect Element: https://www.youtube.com/watch?v=-pT_pDe54aA
-.. _XPather: https://addons.mozilla.org/en-US/firefox/addon/xpather/ 
-.. _XPath Checker: https://addons.mozilla.org/en-US/firefox/addon/xpath-checker/
-.. _Tamper Data: https://addons.mozilla.org/en-US/firefox/addon/tamper-data/
-.. _Firecookie: https://addons.mozilla.org/en-US/firefox/addon/firecookie/
-

docs/topics/item-pipeline.rst

@@ -27,16 +27,22 @@ Each item pipeline component is a Python class that must implement the following
 
 .. method:: process_item(self, item, spider)
 
-   This method is called for every item pipeline component and must either return
-   a dict with data, :class:`~scrapy.item.Item` (or any descendant class) object 
-   or raise a :exc:`~scrapy.exceptions.DropItem` exception. Dropped items are no longer
-   processed by further pipeline components.
+   This method is called for every item pipeline component.
 
-   :param item: the item scraped
-   :type item: :class:`~scrapy.item.Item` object or a dict
+   `item` is an :ref:`item object <item-types>`, see
+   :ref:`supporting-item-types`.
+
+   :meth:`process_item` must either: return an :ref:`item object <item-types>`,
+   return a :class:`~twisted.internet.defer.Deferred` or raise a
+   :exc:`~scrapy.exceptions.DropItem` exception.
+
+   Dropped items are no longer processed by further pipeline components.
+
+   :param item: the scraped item
+   :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:
 
@@ -45,18 +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
@@ -75,39 +81,50 @@ 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(object):
 
+    class PricePipeline:
         vat_factor = 1.15
 
         def process_item(self, item, spider):
-            if item['price']:
-                if item['price_excludes_vat']:
-                    item['price'] = item['price'] * self.vat_factor
+            adapter = ItemAdapter(item)
+            if adapter.get("price"):
+                if adapter.get("price_excludes_vat"):
+                    adapter["price"] = adapter["price"] * self.vat_factor
                 return item
             else:
-                raise DropItem("Missing price in %s" % item)
+                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 a
-single ``items.jl`` file, containing one item per line serialized in JSON
-format::
+The following pipeline stores all scraped items (from all spiders) into a
+single ``items.jsonl`` file, containing one item per line serialized in JSON
+format:
+
+.. code-block:: python
 
    import json
 
-   class JsonWriterPipeline(object):
+   from itemadapter import ItemAdapter
 
-       def __init__(self):
-           self.file = open('items.jl', 'wb')
+
+   class JsonWriterPipeline:
+       def open_spider(self, spider):
+           self.file = open("items.jsonl", "w")
+
+       def close_spider(self, spider):
+           self.file.close()
 
        def process_item(self, item, spider):
-           line = json.dumps(dict(item)) + "\n"
+           line = json.dumps(ItemAdapter(item).asdict()) + "\n"
            self.file.write(line)
            return item
 
@@ -125,18 +142,15 @@ 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.
 
-.. note::
-
-    Previous example (JsonWriterPipeline) doesn't clean up resources properly.
-    Fixing it is left as an exercise for the reader.
-
-::
+.. skip: next
+.. code-block:: python
 
     import pymongo
+    from itemadapter import ItemAdapter
 
-    class MongoPipeline(object):
-    
-        collection_name = 'scrapy_items'
+
+    class MongoPipeline:
+        collection_name = "scrapy_items"
 
         def __init__(self, mongo_uri, mongo_db):
             self.mongo_uri = mongo_uri
@@ -145,8 +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):
@@ -157,32 +171,92 @@ method and how to clean up the resources properly.
             self.client.close()
 
         def process_item(self, item, spider):
-            self.db[self.collection_name].insert(dict(item))
+            self.db[self.collection_name].insert_one(ItemAdapter(item).asdict())
             return item
 
-.. _MongoDB: http://www.mongodb.org/
-.. _pymongo: http://api.mongodb.org/python/current/
+.. _MongoDB: https://www.mongodb.com/
+.. _pymongo: https://api.mongodb.com/python/current/
+
+
+.. _ScreenshotPipeline:
+
+Take screenshot of item
+-----------------------
+
+This example demonstrates how to use :doc:`coroutine syntax <coroutines>` in
+the :meth:`process_item` method.
+
+This item pipeline makes a request to a locally-running instance of Splash_ to
+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
+        every Scrapy item."""
+
+        SPLASH_URL = "http://localhost:8050/render.png?url={}"
+
+        async def process_item(self, item, spider):
+            adapter = ItemAdapter(item)
+            encoded_item_url = quote(adapter["url"])
+            screenshot_url = self.SPLASH_URL.format(encoded_item_url)
+            request = scrapy.Request(screenshot_url, callback=NO_CALLBACK)
+            response = await maybe_deferred_to_future(
+                spider.crawler.engine.download(request, spider)
+            )
+
+            if response.status != 200:
+                # Error happened, return item.
+                return item
+
+            # Save screenshot to file, filename will be hash of url.
+            url = adapter["url"]
+            url_hash = hashlib.md5(url.encode("utf8")).hexdigest()
+            filename = f"{url_hash}.png"
+            Path(filename).write_bytes(response.body)
+
+            # Store filename in item.
+            adapter["screenshot_filename"] = filename
+            return item
+
+.. _Splash: https://splash.readthedocs.io/en/stable/
 
 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(object):
 
+    class DuplicatesPipeline:
         def __init__(self):
             self.ids_seen = set()
 
         def process_item(self, item, spider):
-            if item['id'] in self.ids_seen:
-                raise DropItem("Duplicate item found: %s" % item)
+            adapter = ItemAdapter(item)
+            if adapter["id"] in self.ids_seen:
+                raise DropItem(f"Duplicate item found: {item!r}")
             else:
-                self.ids_seen.add(item['id'])
+                self.ids_seen.add(adapter["id"])
                 return item
 
 
@@ -190,14 +264,15 @@ 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
 order in which they run: items go through from lower valued to higher
 valued classes. It's customary to define these numbers in the 0-1000 range.
-

docs/topics/items.rst

@@ -8,38 +8,171 @@ Items
    :synopsis: Item and Field classes
 
 The main goal in scraping is to extract structured data from unstructured
-sources, typically, web pages. Scrapy spiders can return the extracted data
-as Python dicts. While convenient and familiar, Python dicts lack structure:
-it is easy to make a typo in a field name or return inconsistent data,
-especially in a larger project with many spiders.
+sources, typically, web pages. :ref:`Spiders <topics-spiders>` may return the
+extracted data as `items`, Python objects that define key-value pairs.
 
-To define common output data format Scrapy provides the :class:`Item` class.
-:class:`Item` objects are simple containers used to collect the scraped data.
-They provide a `dictionary-like`_ API with a convenient syntax for declaring
-their available fields. 
+Scrapy supports :ref:`multiple types of items <item-types>`. When you create an
+item, you may use whichever type of item you want. When you write code that
+receives an item, your code should :ref:`work for any item type
+<supporting-item-types>`.
 
-Various Scrapy components use extra information provided by Items: 
-exporters look at declared fields to figure out columns to export,
-serialization can be customized using Item fields metadata, :mod:`trackref`
-tracks Item instances to help finding memory leaks 
-(see :ref:`topics-leaks-trackrefs`), etc.
+.. _item-types:
 
-.. _dictionary-like: https://docs.python.org/2/library/stdtypes.html#dict
+Item Types
+==========
+
+Scrapy supports the following types of items, via the `itemadapter`_ library:
+:ref:`dictionaries <dict-items>`, :ref:`Item objects <item-objects>`,
+:ref:`dataclass objects <dataclass-items>`, and :ref:`attrs objects <attrs-items>`.
+
+.. _itemadapter: https://github.com/scrapy/itemadapter
+
+.. _dict-items:
+
+Dictionaries
+------------
+
+As an item type, :class:`dict` is convenient and familiar.
+
+.. _item-objects:
+
+Item objects
+------------
+
+:class:`Item` provides a :class:`dict`-like API plus additional features that
+make it the most feature-complete item type:
+
+.. class:: scrapy.item.Item([arg])
+.. class:: scrapy.Item([arg])
+
+    :class:`Item` objects replicate the standard :class:`dict` API, including
+    its ``__init__`` method.
+
+    :class:`Item` allows defining field names, so that:
+
+    -   :class:`KeyError` is raised when using undefined field names (i.e.
+        prevents typos going unnoticed)
+
+    -   :ref:`Item exporters <topics-exporters>` can export all fields by
+        default even if the first scraped object does not have values for all
+        of them
+
+    :class:`Item` also allows defining field metadata, which can be used to
+    :ref:`customize serialization <topics-exporters-field-serialization>`.
+
+    :mod:`trackref` tracks :class:`Item` objects to help find memory leaks
+    (see :ref:`topics-leaks-trackrefs`).
+
+    :class:`Item` objects also provide the following additional API members:
+
+    .. automethod:: copy
+
+    .. automethod:: deepcopy
+
+    .. attribute:: fields
+
+        A dictionary containing *all declared fields* for this Item, not only
+        those populated. The keys are the field names and the values are the
+        :class:`Field` objects used in the :ref:`Item declaration
+        <topics-items-declaring>`.
+
+Example:
+
+.. code-block:: python
+
+    from scrapy.item import Item, Field
+
+
+    class CustomItem(Item):
+        one_field = Field()
+        another_field = Field()
+
+.. _dataclass-items:
+
+Dataclass objects
+-----------------
+
+.. versionadded:: 2.2
+
+:func:`~dataclasses.dataclass` allows defining item classes with field names,
+so that :ref:`item exporters <topics-exporters>` can export all fields by
+default even if the first scraped object does not have values for all of them.
+
+Additionally, ``dataclass`` items also allow to:
+
+* define the type and default value of each defined field.
+
+* define custom field metadata through :func:`dataclasses.field`, which can be used to
+  :ref:`customize serialization <topics-exporters-field-serialization>`.
+
+Example:
+
+.. code-block:: python
+
+    from dataclasses import dataclass
+
+
+    @dataclass
+    class CustomItem:
+        one_field: str
+        another_field: int
+
+.. note:: Field types are not enforced at run time.
+
+.. _attrs-items:
+
+attr.s objects
+--------------
+
+.. versionadded:: 2.2
+
+:func:`attr.s` allows defining item classes with field names,
+so that :ref:`item exporters <topics-exporters>` can export all fields by
+default even if the first scraped object does not have values for all of them.
+
+Additionally, ``attr.s`` items also allow to:
+
+* define the type and default value of each defined field.
+
+* define custom field :ref:`metadata <attrs:metadata>`, which can be used to
+  :ref:`customize serialization <topics-exporters-field-serialization>`.
+
+In order to use this type, the :doc:`attrs package <attrs:index>` needs to be installed.
+
+Example:
+
+.. code-block:: python
+
+    import attr
+
+
+    @attr.s
+    class CustomItem:
+        one_field = attr.ib()
+        another_field = attr.ib()
+
+
+Working with Item objects
+=========================
 
 .. _topics-items-declaring:
 
-Declaring Items
-===============
+Declaring Item subclasses
+-------------------------
 
-Items are declared using a simple class definition syntax and :class:`Field`
-objects. Here is an example::
+Item subclasses are declared using a simple class definition syntax and
+:class:`Field` objects. Here is an example:
+
+.. code-block:: python
 
     import scrapy
 
+
     class Product(scrapy.Item):
         name = scrapy.Field()
         price = scrapy.Field()
         stock = scrapy.Field()
+        tags = scrapy.Field()
         last_updated = scrapy.Field(serializer=str)
 
 .. note:: Those familiar with `Django`_ will notice that Scrapy Items are
@@ -49,10 +182,11 @@ objects. Here is an example::
 .. _Django: https://www.djangoproject.com/
 .. _Django Models: https://docs.djangoproject.com/en/dev/topics/db/models/
 
+
 .. _topics-items-fields:
 
-Item Fields
-===========
+Declaring fields
+----------------
 
 :class:`Field` objects are used to specify metadata for each field. For
 example, the serializer function for the ``last_updated`` field illustrated in
@@ -61,7 +195,7 @@ the example above.
 You can specify any kind of metadata for each field. There is no restriction on
 the values accepted by :class:`Field` objects. For this same
 reason, there is no reference list of all available metadata keys. Each key
-defined in :class:`Field` objects could be used by a different components, and
+defined in :class:`Field` objects could be used by a different component, and
 only those components know about it. You can also define and use any other
 :class:`Field` key in your project too, for your own needs. The main goal of
 :class:`Field` objects is to provide a way to define all field metadata in one
@@ -73,81 +207,103 @@ 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.
 
-Working with Items
-==================
+.. 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,
+    :class:`Field` objects are plain-old Python dicts. A separate class is used
+    to support the :ref:`item declaration syntax <topics-items-declaring>`
+    based on class attributes.
+
+.. note:: Field metadata can also be declared for ``dataclass`` and ``attrs``
+    items. Please refer to the documentation for `dataclasses.field`_ and
+    `attr.ib`_ for additional information.
+
+    .. _dataclasses.field: https://docs.python.org/3/library/dataclasses.html#dataclasses.field
+    .. _attr.ib: https://www.attrs.org/en/stable/api.html#attr.ib
+
+
+Working with Item objects
+-------------------------
 
 Here are some examples of common tasks performed with items, using the
 ``Product`` item :ref:`declared above  <topics-items-declaring>`. You will
-notice the API is very similar to the `dict API`_.
+notice the API is very similar to the :class:`dict` API.
 
 Creating items
---------------
+''''''''''''''
 
-::
+.. code-block:: pycon
 
-    >>> product = Product(name='Desktop PC', price=1000)
-    >>> print product
+    >>> product = Product(name="Desktop PC", price=1000)
+    >>> print(product)
     Product(name='Desktop PC', price=1000)
 
+
 Getting field values
---------------------
+''''''''''''''''''''
 
-::
+.. code-block:: pycon
 
-    >>> product['name']
+    >>> product["name"]
     Desktop PC
-    >>> product.get('name')
+    >>> product.get("name")
     Desktop PC
 
-    >>> product['price']
+    >>> product["price"]
     1000
 
-    >>> product['last_updated']
+    >>> product["last_updated"]
     Traceback (most recent call last):
         ...
     KeyError: 'last_updated'
 
-    >>> product.get('last_updated', 'not set')
+    >>> product.get("last_updated", "not set")
     not set
 
-    >>> product['lala'] # getting unknown field
+    >>> product["lala"]  # getting unknown field
     Traceback (most recent call last):
         ...
     KeyError: 'lala'
 
-    >>> product.get('lala', 'unknown field')
+    >>> product.get("lala", "unknown field")
     'unknown field'
 
-    >>> 'name' in product  # is name field populated?
+    >>> "name" in product  # is name field populated?
     True
 
-    >>> 'last_updated' in product  # is last_updated populated?
+    >>> "last_updated" in product  # is last_updated populated?
     False
 
-    >>> 'last_updated' in product.fields  # is last_updated a declared field?
+    >>> "last_updated" in product.fields  # is last_updated a declared field?
     True
 
-    >>> 'lala' in product.fields  # is lala a declared field?
+    >>> "lala" in product.fields  # is lala a declared field?
     False
 
+
 Setting field values
---------------------
+''''''''''''''''''''
 
-::
+.. code-block:: pycon
 
-    >>> product['last_updated'] = 'today'
-    >>> product['last_updated']
+    >>> product["last_updated"] = "today"
+    >>> product["last_updated"]
     today
 
-    >>> product['lala'] = 'test' # setting unknown field
+    >>> product["lala"] = "test"  # setting unknown field
     Traceback (most recent call last):
         ...
     KeyError: 'Product does not support field: lala'
 
-Accessing all populated values
-------------------------------
 
-To access all populated values, just use the typical `dict API`_::
+Accessing all populated values
+''''''''''''''''''''''''''''''
+
+To access all populated values, just use the typical :class:`dict` API:
+
+.. code-block:: pycon
 
     >>> product.keys()
     ['price', 'name']
@@ -155,85 +311,102 @@ To access all populated values, just use the typical `dict API`_::
     >>> product.items()
     [('price', 1000), ('name', 'Desktop PC')]
 
+
+.. _copying-items:
+
+Copying items
+'''''''''''''
+
+To copy an item, you must first decide whether you want a shallow copy or a
+deep copy.
+
+If your item contains :term:`mutable` values like lists or dictionaries,
+a shallow copy will keep references to the same mutable values across all
+different copies.
+
+For example, if you have an item with a list of tags, and you create a shallow
+copy of that item, both the original item and the copy have the same list of
+tags. Adding a tag to the list of one of the items will add the tag to the
+other item as well.
+
+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.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.deepcopy` instead
+(``product2 = product.deepcopy()``).
+
+
 Other common tasks
-------------------
+''''''''''''''''''
 
-Copying items::
+Creating dicts from items:
 
-    >>> product2 = Product(product)
-    >>> print product2
-    Product(name='Desktop PC', price=1000)
+.. code-block:: pycon
 
-    >>> product3 = product2.copy()
-    >>> print product3
-    Product(name='Desktop PC', price=1000)
-
-Creating dicts from items::
-
-    >>> dict(product) # create a dict from all populated values
+    >>> dict(product)  # create a dict from all populated values
     {'price': 1000, 'name': 'Desktop PC'}
 
-Creating items from dicts::
+    Creating items from dicts:
 
-    >>> Product({'name': 'Laptop PC', 'price': 1500})
+    >>> Product({"name": "Laptop PC", "price": 1500})
     Product(price=1500, name='Laptop PC')
 
-    >>> Product({'name': 'Laptop PC', 'lala': 1500}) # warning: unknown field in dict
+    >>> Product({"name": "Laptop PC", "lala": 1500})  # warning: unknown field in dict
     Traceback (most recent call last):
         ...
     KeyError: 'Product does not support field: lala'
 
-Extending Items
-===============
+
+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.
 
-Item objects
-============
 
-.. class:: Item([arg])
+.. _supporting-item-types:
 
-    Return a new Item optionally initialized from the given argument.
+Supporting All Item Types
+=========================
 
-    Items replicate the standard `dict API`_, including its constructor. The
-    only additional attribute provided by Items is:
+In code that receives an item, such as methods of :ref:`item pipelines
+<topics-item-pipeline>` or :ref:`spider middlewares
+<topics-spider-middleware>`, it is a good practice to use the
+:class:`~itemadapter.ItemAdapter` class and the
+:func:`~itemadapter.is_item` function to write code that works for
+any :ref:`supported item type <item-types>`:
 
-    .. attribute:: fields
+.. autoclass:: itemadapter.ItemAdapter
 
-        A dictionary containing *all declared fields* for this Item, not only
-        those populated. The keys are the field names and the values are the
-        :class:`Field` objects used in the :ref:`Item declaration
-        <topics-items-declaring>`.
-
-.. _dict API: https://docs.python.org/2/library/stdtypes.html#dict
-
-Field objects
-=============
-
-.. class:: Field([arg])
-
-    The :class:`Field` class is just an alias to the built-in `dict`_ class and
-    doesn't provide any extra functionality or attributes. In other words,
-    :class:`Field` objects are plain-old Python dicts. A separate class is used
-    to support the :ref:`item declaration syntax <topics-items-declaring>`
-    based on class attributes.
-
-.. _dict: https://docs.python.org/2/library/stdtypes.html#dict
+.. autofunction:: itemadapter.is_item
 
 
+Other classes related to items
+==============================
+
+.. autoclass:: ItemMeta

docs/topics/jobs.rst

@@ -22,7 +22,7 @@ Job directory
 
 To enable persistence support you just need to define a *job directory* through
 the ``JOBDIR`` setting. This directory will be for storing all required data to
-keep the state of a single job (ie. a spider run).  It's important to note that
+keep the state of a single job (i.e. a spider run).  It's important to note that
 this directory must not be shared by different spiders, or even different
 jobs/runs of the same spider, as it's meant to be used for storing the state of
 a *single* job.
@@ -30,7 +30,7 @@ a *single* job.
 How to use it
 =============
 
-To start a spider with persistence supported enabled, run it like this::
+To start a spider with persistence support enabled, run it like this::
 
     scrapy crawl somespider -s JOBDIR=crawls/somespider-1
 
@@ -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
 ===================
@@ -65,35 +69,20 @@ Cookies expiration
 ------------------
 
 Cookies may expire. So, if you don't resume your spider quickly the requests
-scheduled may no longer work. This won't be an issue if you spider doesn't rely
+scheduled may no longer work. This won't be an issue if your spider doesn't rely
 on cookies.
 
+
+.. _request-serialization:
+
 Request serialization
 ---------------------
 
-Requests must be serializable by the `pickle` module, in order for persistence
-to work, so you should make sure that your requests are serializable.
+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.Spider` class.
 
-The most common issue here is to use ``lambda`` functions on request callbacks that
-can't be persisted.
-
-So, for example, this won't work::
-
-    def some_callback(self, response):
-        somearg = 'test'
-        return scrapy.Request('http://www.example.com', callback=lambda r: self.other_callback(r, somearg))
-
-    def other_callback(self, response, somearg):
-        print "the argument passed is:", somearg
-
-But this will::
-
-    def some_callback(self, response):
-        somearg = 'test'
-        return scrapy.Request('http://www.example.com', callback=self.other_callback, meta={'somearg': somearg})
-
-    def other_callback(self, response):
-        somearg = response.meta['somearg']
-        print "the argument passed is:", somearg
-
-.. _pickle: http://docs.python.org/library/pickle.html
+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.
+It is ``False`` by default.

docs/topics/leaks.rst

@@ -4,7 +4,7 @@
 Debugging memory leaks
 ======================
 
-In Scrapy, objects such as Requests, Responses and Items have a finite
+In Scrapy, objects such as requests, responses and items have a finite
 lifetime: they are created, used for a while, and finally destroyed.
 
 From all those objects, the Request is probably the one with the longest
@@ -17,8 +17,8 @@ what is known as a "memory leak".
 
 To help debugging memory leaks, Scrapy provides a built-in mechanism for
 tracking objects references called :ref:`trackref <topics-leaks-trackrefs>`,
-and you can also use a third-party library called :ref:`Guppy
-<topics-leaks-guppy>` for more advanced memory debugging (see below for more
+and you can also use a third-party library called :ref:`muppy
+<topics-leaks-muppy>` for more advanced memory debugging (see below for more
 info). Both mechanisms must be used from the :ref:`Telnet Console
 <topics-telnetconsole>`.
 
@@ -27,10 +27,11 @@ 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.meta` attribute 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 difficult one to debug for newcomers.
+: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
+difficult one to debug for newcomers.
 
 In big projects, the spiders are typically written by different people and some
 of those spiders could be "leaking" and thus affecting the rest of the other
@@ -47,8 +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.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.
@@ -59,8 +61,8 @@ Debugging memory leaks with ``trackref``
 ========================================
 
 :mod:`trackref` is a module provided by Scrapy to debug the most common cases of
-memory leaks. It basically tracks the references to all live Requests,
-Responses, Item and Selector objects.
+memory leaks. It basically tracks the references to all live Request,
+Response, Item, Spider and Selector objects.
 
 You can enter the telnet console and inspect how many objects (of the classes
 mentioned above) are currently alive using the ``prefs()`` function which is an
@@ -68,13 +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
@@ -88,31 +92,33 @@ 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
 --------------
 
-Let's see a concrete example of an hypothetical case of memory leaks.
+Let's see a concrete example of a hypothetical case of memory leaks.
 Suppose we have some spider with a line similar to this one::
 
-    return Request("http://www.somenastyspider.com/product.php?pid=%d" % product_id,
-        callback=self.parse, meta={referer: response})
+    return Request(f"http://www.somenastyspider.com/product.php?pid={product_id}",
+                   callback=self.parse, cb_kwargs={'referer': response})
 
 That line is passing a response reference inside a request which effectively
 ties the response lifetime to the requests' one, and that would definitely
 cause memory leaks.
 
 Let's see how we can discover the cause (without knowing it
-a-priori, of course) by using the ``trackref`` tool.
+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
@@ -130,21 +136,25 @@ and check the code of the spider to discover the nasty line that is
 generating the leaks (passing response references inside requests).
 
 Sometimes extra information about live objects can be helpful.
-Let's check the oldest response::
+Let's check the oldest response:
+
+.. code-block:: pycon
 
     >>> from scrapy.utils.trackref import get_oldest
-    >>> r = get_oldest('HtmlResponse')
+    >>> 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::
+can use the :func:`scrapy.utils.trackref.iter_all` function:
+
+.. code-block:: pycon
 
     >>> from scrapy.utils.trackref import iter_all
-    >>> [r.url for r in iter_all('HtmlResponse')]
+    >>> [r.url for r in iter_all("HtmlResponse")]
     ['http://www.somenastyspider.com/product.php?pid=123',
-     'http://www.somenastyspider.com/product.php?pid=584',
-    ...
+    'http://www.somenastyspider.com/product.php?pid=584',
+    ...]
 
 Too many spiders?
 -----------------
@@ -152,8 +162,10 @@ 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
-example, this won't show any live references to spiders::
+ignore a particular class (and all its subclasses). For
+example, this won't show any live references to spiders:
+
+.. code-block:: pycon
 
     >>> from scrapy.spiders import Spider
     >>> prefs(ignore=Spider)
@@ -168,7 +180,7 @@ Here are the functions available in the :mod:`~scrapy.utils.trackref` module.
 
 .. class:: object_ref
 
-    Inherit from this class (instead of object) if you want to track live
+    Inherit from this class if you want to track live
     instances with the ``trackref`` module.
 
 .. function:: print_live_refs(class_name, ignore=NoneType)
@@ -177,7 +189,7 @@ Here are the functions available in the :mod:`~scrapy.utils.trackref` module.
 
     :param ignore: if given, all objects from the specified class (or tuple of
         classes) will be ignored.
-    :type ignore: class or classes tuple
+    :type ignore: type or tuple
 
 .. function:: get_oldest(class_name)
 
@@ -191,67 +203,59 @@ Here are the functions available in the :mod:`~scrapy.utils.trackref` module.
     ``None`` if none is found. Use :func:`print_live_refs` first to get a list
     of all tracked live objects per class name.
 
-.. _topics-leaks-guppy:
+.. _topics-leaks-muppy:
 
-Debugging memory leaks with Guppy
+Debugging memory leaks with muppy
 =================================
 
 ``trackref`` provides a very convenient mechanism for tracking down memory
 leaks, but it only keeps track of the objects that are more likely to cause
-memory leaks (Requests, Responses, Items, and Selectors). However, there are
-other cases where the memory leaks could come from other (more or less obscure)
-objects. If this is your case, and you can't find your leaks using ``trackref``,
-you still have another resource: the `Guppy library`_.
+memory leaks. However, there are other cases where the memory leaks could come
+from other (more or less obscure) objects. If this is your case, and you can't
+find your leaks using ``trackref``, you still have another resource: the muppy
+library.
 
-.. _Guppy library: https://pypi.python.org/pypi/guppy
+You can use muppy from `Pympler`_.
 
-If you use ``pip``, you can install Guppy with the following command::
+.. _Pympler: https://pypi.org/project/Pympler/
 
-    pip install guppy
+If you use ``pip``, you can install muppy with the following command::
 
-The telnet console also comes with a built-in shortcut (``hpy``) for accessing
-Guppy heap objects. Here's an example to view all Python objects available in
-the heap using Guppy::
+    pip install Pympler
 
-    >>> x = hpy.heap()
-    >>> x.bytype
-    Partition of a set of 297033 objects. Total size = 52587824 bytes.
-     Index  Count   %     Size   % Cumulative  % Type
-         0  22307   8 16423880  31  16423880  31 dict
-         1 122285  41 12441544  24  28865424  55 str
-         2  68346  23  5966696  11  34832120  66 tuple
-         3    227   0  5836528  11  40668648  77 unicode
-         4   2461   1  2222272   4  42890920  82 type
-         5  16870   6  2024400   4  44915320  85 function
-         6  13949   5  1673880   3  46589200  89 types.CodeType
-         7  13422   5  1653104   3  48242304  92 list
-         8   3735   1  1173680   2  49415984  94 _sre.SRE_Pattern
-         9   1209   0   456936   1  49872920  95 scrapy.http.headers.Headers
-    <1676 more rows. Type e.g. '_.more' to view.>
+Here's an example to view all Python objects available in
+the heap using muppy:
 
-You can see that most space is used by dicts. Then, if you want to see from
-which attribute those dicts are referenced, you could do::
+.. code-block:: pycon
 
-    >>> x.bytype[0].byvia
-    Partition of a set of 22307 objects. Total size = 16423880 bytes.
-     Index  Count   %     Size   % Cumulative  % Referred Via:
-         0  10982  49  9416336  57   9416336  57 '.__dict__'
-         1   1820   8  2681504  16  12097840  74 '.__dict__', '.func_globals'
-         2   3097  14  1122904   7  13220744  80
-         3    990   4   277200   2  13497944  82 "['cookies']"
-         4    987   4   276360   2  13774304  84 "['cache']"
-         5    985   4   275800   2  14050104  86 "['meta']"
-         6    897   4   251160   2  14301264  87 '[2]'
-         7      1   0   196888   1  14498152  88 "['moduleDict']", "['modules']"
-         8    672   3   188160   1  14686312  89 "['cb_kwargs']"
-         9     27   0   155016   1  14841328  90 '[1]'
-    <333 more rows. Type e.g. '_.more' to view.>
+    >>> 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
 
-As you can see, the Guppy module is very powerful but also requires some deep
-knowledge about Python internals. For more info about Guppy, refer to the
-`Guppy documentation`_.
+For more info about muppy, refer to the `muppy documentation`_.
 
-.. _Guppy documentation: http://guppy-pe.sourceforge.net/
+.. _muppy documentation: https://pythonhosted.org/Pympler/muppy.html
 
 .. _topics-leaks-without-leaks:
 
@@ -264,9 +268,9 @@ though neither Scrapy nor your project are leaking memory. This is due to a
 (not so well) known problem of Python, which may not return released memory to
 the operating system in some cases. For more information on this issue see:
 
-* `Python Memory Management <http://www.evanjones.ca/python-memory.html>`_
-* `Python Memory Management Part 2 <http://www.evanjones.ca/python-memory-part2.html>`_
-* `Python Memory Management Part 3 <http://www.evanjones.ca/python-memory-part3.html>`_
+* `Python Memory Management <https://www.evanjones.ca/python-memory.html>`_
+* `Python Memory Management Part 2 <https://www.evanjones.ca/python-memory-part2.html>`_
+* `Python Memory Management Part 3 <https://www.evanjones.ca/python-memory-part3.html>`_
 
 The improvements proposed by Evan Jones, which are detailed in `this paper`_,
 got merged in Python 2.5, but this only reduces the problem, it doesn't fix it
@@ -280,7 +284,7 @@ completely. To quote the paper:
     to move to a compacting garbage collector, which is able to move objects in
     memory. This would require significant changes to the Python interpreter.*
 
-.. _this paper: http://www.evanjones.ca/memoryallocator/
+.. _this paper: https://www.evanjones.ca/memoryallocator/
 
 To keep memory consumption reasonable you can split the job into several
 smaller jobs or enable :ref:`persistent job queue <topics-jobs>`

docs/topics/link-extractors.rst

@@ -4,46 +4,42 @@
 Link Extractors
 ===============
 
-Link extractors are objects whose only purpose is to extract links from web
-pages (:class:`scrapy.http.Response` objects) which will be eventually
-followed.
+A link extractor is an object that extracts links from responses.
 
-There is ``scrapy.linkextractors import LinkExtractor`` available
-in Scrapy, but you can create your own custom Link Extractors to suit your
-needs by implementing a simple interface.
+The ``__init__`` method of
+:class:`~scrapy.linkextractors.lxmlhtml.LxmlLinkExtractor` takes settings that
+determine which links may be extracted. :class:`LxmlLinkExtractor.extract_links
+<scrapy.linkextractors.lxmlhtml.LxmlLinkExtractor.extract_links>` returns a
+list of matching :class:`~scrapy.link.Link` objects from a
+:class:`~scrapy.http.Response` object.
 
-The only public method that every link extractor has is ``extract_links``,
-which receives a :class:`~scrapy.http.Response` object and returns a list
-of :class:`scrapy.link.Link` objects. Link extractors are meant to be
-instantiated once and their ``extract_links`` method called several times
-with different responses to extract links to follow.
+Link extractors are used in :class:`~scrapy.spiders.CrawlSpider` spiders
+through a set of :class:`~scrapy.spiders.Rule` objects.
 
-Link extractors are used in the :class:`~scrapy.spiders.CrawlSpider`
-class (available in Scrapy), through a set of rules, but you can also use it in
-your spiders, even if you don't subclass from
-:class:`~scrapy.spiders.CrawlSpider`, as its purpose is very simple: to
-extract links.
+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:
 
+.. code-block:: python
+
+    def parse(self, response):
+        for link in self.link_extractor.extract_links(response):
+            yield Request(link.url, callback=self.parse)
 
 .. _topics-link-extractors-ref:
 
-Built-in link extractors reference
-==================================
+Link extractor reference
+========================
 
 .. module:: scrapy.linkextractors
    :synopsis: Link extractors classes
 
-Link extractors classes bundled with Scrapy are provided in the
-:mod:`scrapy.linkextractors` module.
-
-The default link extractor is ``LinkExtractor``, which is the same as
-:class:`~.LxmlLinkExtractor`::
+The link extractor class is
+:class:`scrapy.linkextractors.lxmlhtml.LxmlLinkExtractor`. For convenience it
+can also be imported as ``scrapy.linkextractors.LinkExtractor``::
 
     from scrapy.linkextractors import LinkExtractor
 
-There used to be other link extractor classes in previous Scrapy versions,
-but they are deprecated now.
-
 LxmlLinkExtractor
 -----------------
 
@@ -51,7 +47,7 @@ LxmlLinkExtractor
    :synopsis: lxml's HTMLParser-based link extractors
 
 
-.. class:: LxmlLinkExtractor(allow=(), deny=(), allow_domains=(), deny_domains=(), deny_extensions=None, restrict_xpaths=(), restrict_css=(), tags=('a', 'area'), attrs=('href',), canonicalize=True, unique=True, process_value=None)
+.. class:: LxmlLinkExtractor(allow=(), deny=(), allow_domains=(), deny_domains=(), deny_extensions=None, restrict_xpaths=(), restrict_css=(), tags=('a', 'area'), attrs=('href',), canonicalize=False, unique=True, process_value=None, strip=True)
 
     LxmlLinkExtractor is the recommended link extractor with handy filtering
     options. It is implemented using lxml's robust HTMLParser.
@@ -59,13 +55,13 @@ LxmlLinkExtractor
     :param allow: a single regular expression (or list of regular expressions)
         that the (absolute) urls must match in order to be extracted. If not
         given (or empty), it will match all links.
-    :type allow: a regular expression (or list of)
+    :type allow: str or list
 
     :param deny: a single regular expression (or list of regular expressions)
-        that the (absolute) urls must match in order to be excluded (ie. not
+        that the (absolute) urls must match in order to be excluded (i.e. not
         extracted). It has precedence over the ``allow`` parameter. If not
         given (or empty) it won't exclude any links.
-    :type deny: a regular expression (or list of)
+    :type deny: str or list
 
     :param allow_domains: a single value or a list of string containing
         domains which will be considered for extracting the links
@@ -77,9 +73,13 @@ LxmlLinkExtractor
 
     :param deny_extensions: a single value or list of strings containing
         extensions that should be ignored when extracting links.
-        If not given, it will default to the
-        ``IGNORED_EXTENSIONS`` list defined in the
-        `scrapy.linkextractors`_ package.
+        If not given, it will default to
+        :data:`scrapy.linkextractors.IGNORED_EXTENSIONS`.
+
+        .. versionchanged:: 2.0
+           :data:`~scrapy.linkextractors.IGNORED_EXTENSIONS` now includes
+           ``7z``, ``7zip``, ``apk``, ``bz2``, ``cdr``, ``dmg``, ``ico``,
+           ``iso``, ``tar``, ``tar.gz``, ``webm``, and ``xz``.
     :type deny_extensions: list
 
     :param restrict_xpaths: is an XPath (or list of XPath's) which defines
@@ -93,6 +93,12 @@ LxmlLinkExtractor
         Has the same behaviour as ``restrict_xpaths``.
     :type restrict_css: str or list
 
+    :param restrict_text: a single regular expression (or list of regular expressions)
+        that the link's text must match in order to be extracted. If not
+        given (or empty), it will match all links. If a list of regular expressions is
+        given, the link will be extracted if it matches at least one.
+    :type restrict_text: str or list
+
     :param tags: a tag or a list of tags to consider when extracting links.
         Defaults to ``('a', 'area')``.
     :type tags: str or list
@@ -103,12 +109,17 @@ LxmlLinkExtractor
     :type attrs: list
 
     :param canonicalize: canonicalize each extracted url (using
-        scrapy.utils.url.canonicalize_url). Defaults to ``True``.
-    :type canonicalize: boolean
+        w3lib.url.canonicalize_url). Defaults to ``False``.
+        Note that canonicalize_url is meant for duplicate checking;
+        it can change the URL visible at server side, so the response can be
+        different for requests with canonicalized and raw URLs. If you're
+        using LinkExtractor to follow links it is more robust to
+        keep the default ``canonicalize=False``.
+    :type canonicalize: bool
 
     :param unique: whether duplicate filtering should be applied to extracted
         links.
-    :type unique: boolean
+    :type unique: bool
 
     :param process_value: a function which receives each value extracted from
         the tag and attributes scanned and can modify the value and return a
@@ -123,13 +134,34 @@ 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)
 
-    :type process_value: callable
+    :type process_value: collections.abc.Callable
+
+    :param strip: whether to strip whitespaces from extracted attributes.
+        According to HTML5 standard, leading and trailing whitespaces
+        must be stripped from ``href`` attributes of ``<a>``, ``<area>``
+        and many other elements, ``src`` attribute of ``<img>``, ``<iframe>``
+        elements, etc., so LinkExtractor strips space chars by default.
+        Set ``strip=False`` to turn it off (e.g. if you're extracting urls
+        from elements or attributes which allow leading/trailing whitespaces).
+    :type strip: bool
+
+    .. automethod:: extract_links
+
+Link
+----
+
+.. module:: scrapy.link
+   :synopsis: Link from link extractors
+
+.. autoclass:: Link
 
 .. _scrapy.linkextractors: https://github.com/scrapy/scrapy/blob/master/scrapy/linkextractors/__init__.py

docs/topics/loaders.rst

@@ -7,13 +7,12 @@ Item Loaders
 .. module:: scrapy.loader
    :synopsis: Item Loader class
 
-Item Loaders provide a convenient mechanism for populating scraped :ref:`Items
-<topics-items>`. Even though Items can be populated using their own
-dictionary-like API, Item Loaders provide a much more convenient API for
-populating them from a scraping process, by automating some common tasks like
-parsing the raw extracted data before assigning it.
+Item Loaders provide a convenient mechanism for populating scraped :ref:`items
+<topics-items>`. Even though items can be populated directly, Item Loaders provide a
+much more convenient API for populating them from a scraping process, by automating
+some common tasks like parsing the raw extracted data before assigning it.
 
-In other words, :ref:`Items <topics-items>` provide the *container* of
+In other words, :ref:`items <topics-items>` provide the *container* of
 scraped data, while Item Loaders provide the mechanism for *populating* that
 container.
 
@@ -21,34 +20,47 @@ Item Loaders are designed to provide a flexible, efficient and easy mechanism
 for extending and overriding different field parsing rules, either by spider,
 or by source format (HTML, XML, etc) without becoming a nightmare to maintain.
 
+.. note:: Item Loaders are an extension of the itemloaders_ library that make it
+    easier to work with Scrapy by adding support for
+    :ref:`responses <topics-request-response>`.
+
 Using Item Loaders to populate items
 ====================================
 
 To use an Item Loader, you must first instantiate it. You can either
-instantiate it with a dict-like object (e.g. Item or dict) or without one, in
-which case an Item is automatically instantiated in the Item Loader constructor
-using the Item class specified in the :attr:`ItemLoader.default_item_class`
-attribute.
+instantiate it with an :ref:`item object <topics-items>` or without one, in which
+case an :ref:`item object <topics-items>` is automatically created in the
+Item Loader ``__init__`` method using the :ref:`item <topics-items>` class
+specified in the :attr:`ItemLoader.default_item_class` attribute.
 
 Then, you start collecting values into the Item Loader, typically using
 :ref:`Selectors <topics-selectors>`. You can add more than one value to
 the same item field; the Item Loader will know how to "join" those values later
 using a proper processing function.
 
+.. note:: Collected data is internally stored as lists,
+   allowing to add several values to the same field.
+   If an ``item`` argument is passed when creating a loader,
+   each of the item's values will be stored as-is if it's already
+   an iterable, or wrapped with a list if it's a single value.
+
 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
@@ -62,7 +74,7 @@ locations, using the :meth:`~ItemLoader.add_xpath` method. This is the
 data that will be assigned to the ``name`` field later.
 
 Afterwards, similar calls are used for ``price`` and ``stock`` fields
-(the later using a CSS selector with the :meth:`~ItemLoader.add_css` method),
+(the latter using a CSS selector with the :meth:`~ItemLoader.add_css` method),
 and finally the ``last_update`` field is populated directly with a literal value
 (``today``) using a different method: :meth:`~ItemLoader.add_value`.
 
@@ -71,6 +83,34 @@ called which actually returns the item populated with the data
 previously extracted and collected with the :meth:`~ItemLoader.add_xpath`,
 :meth:`~ItemLoader.add_css`, and :meth:`~ItemLoader.add_value` calls.
 
+
+.. _topics-loaders-dataclass:
+
+Working with dataclass items
+============================
+
+By default, :ref:`dataclass items <dataclass-items>` require all fields to be
+passed when created. This could be an issue when using dataclass items with
+item loaders: unless a pre-populated item is passed to the loader, fields
+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:
+
+.. code-block:: python
+
+    from dataclasses import dataclass, field
+    from typing import Optional
+
+
+    @dataclass
+    class InventoryItem:
+        name: Optional[str] = field(default=None)
+        price: Optional[float] = field(default=None)
+        stock: Optional[int] = field(default=None)
+
+
 .. _topics-loaders-processors:
 
 Input and Output processors
@@ -82,20 +122,22 @@ received (through the :meth:`~ItemLoader.add_xpath`, :meth:`~ItemLoader.add_css`
 :meth:`~ItemLoader.add_value` methods) and the result of the input processor is
 collected and kept inside the ItemLoader. After collecting all data, the
 :meth:`ItemLoader.load_item` method is called to populate and get the populated
-:class:`~scrapy.item.Item` object.  That's when the output processor is
+:ref:`item object <topics-items>`.  That's when the output processor is
 called with the data previously collected (and processed using the input
 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:
 
@@ -128,9 +170,12 @@ So what happens is:
 It's worth noticing that processors are just callable objects, which are called
 with the data to be parsed, and return a parsed value. So you can use any
 function as input or output processor. The only requirement is that they must
-accept one (and only one) positional argument, which will be an iterator.
+accept one (and only one) positional argument, which will be an iterable.
 
-.. note:: Both input and output processors must receive an iterator as their
+.. versionchanged:: 2.0
+   Processors no longer need to be methods.
+
+.. note:: Both input and output processors must receive an iterable as their
    first argument. The output of those functions can be anything. The result of
    input processors will be appended to an internal list (in the Loader)
    containing the collected values (for that field). The result of the output
@@ -140,27 +185,28 @@ The other thing you need to keep in mind is that the values returned by input
 processors are collected internally (in lists) and then passed to output
 processors to populate the fields.
 
-Last, but not least, Scrapy comes with some :ref:`commonly used processors
-<topics-loaders-available-processors>` built-in for convenience.
+Last, but not least, itemloaders_ comes with some :ref:`commonly used
+processors <itemloaders:built-in-processors>` built-in for convenience.
 
 
 Declaring Item Loaders
 ======================
 
-Item Loaders are declared like Items, by 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
-    from scrapy.loader.processors import TakeFirst, MapCompose, Join
+
 
     class ProductLoader(ItemLoader):
-
         default_output_processor = TakeFirst()
 
-        name_in = MapCompose(unicode.title)
+        name_in = MapCompose(str.title)
         name_out = Join()
 
-        price_in = MapCompose(unicode.strip)
+        price_in = MapCompose(str.strip)
 
         # ...
 
@@ -179,16 +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 scrapy.loader.processors import Join, MapCompose, TakeFirst
+    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),
@@ -199,14 +249,15 @@ metadata. Here is an example::
             output_processor=TakeFirst(),
         )
 
-::
+
+.. code-block:: pycon
 
     >>> from scrapy.loader import ItemLoader
     >>> il = ItemLoader(item=Product())
-    >>> il.add_value('name', [u'Welcome to my', u'<strong>website</strong>'])
-    >>> il.add_value('price', [u'&euro;', u'<span>1000</span>'])
+    >>> il.add_value("name", ["Welcome to my", "<strong>website</strong>"])
+    >>> il.add_value("price", ["&euro;", "<span>1000</span>"])
     >>> il.load_item()
-    {'name': u'Welcome to my website', 'price': u'1000'}
+    {'name': 'Welcome to my website', 'price': '1000'}
 
 The precedence order, for both input and output processors, is as follows:
 
@@ -229,10 +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
 
@@ -244,267 +297,36 @@ 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
-   constructor 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
 ==================
 
-.. class:: ItemLoader([item, selector, response], \**kwargs)
-
-    Return a new Item Loader for populating the given Item. If no item is
-    given, one is instantiated automatically using the class in
-    :attr:`default_item_class`.
-
-    When instantiated with a `selector` or a `response` parameters
-    the :class:`ItemLoader` class provides convenient mechanisms for extracting
-    data from web pages using :ref:`selectors <topics-selectors>`.
-
-    :param item: The item instance to populate using subsequent calls to
-        :meth:`~ItemLoader.add_xpath`, :meth:`~ItemLoader.add_css`,
-        or :meth:`~ItemLoader.add_value`.
-    :type item: :class:`~scrapy.item.Item` object
-
-    :param selector: The selector to extract data from, when using the
-        :meth:`add_xpath` (resp. :meth:`add_css`) or :meth:`replace_xpath`
-        (resp. :meth:`replace_css`) method.
-    :type selector: :class:`~scrapy.selector.Selector` object
-
-    :param response: The response used to construct the selector using the
-        :attr:`default_selector_class`, unless the selector argument is given,
-        in which case this argument is ignored.
-    :type response: :class:`~scrapy.http.Response` object
-
-    The item, selector, response and the remaining keyword arguments are
-    assigned to the Loader context (accessible through the :attr:`context` attribute).
-
-    :class:`ItemLoader` instances have the following methods:
-
-    .. method:: get_value(value, \*processors, \**kwargs)
-
-        Process the given ``value`` by the given ``processors`` and keyword
-        arguments.
-
-        Available keyword arguments:
-
-        :param re: a regular expression to use for extracting data from the
-            given value using :meth:`~scrapy.utils.misc.extract_regex` method,
-            applied before processors
-        :type re: str or compiled regex
-
-        Examples::
-
-            >>> from scrapy.loader.processors import TakeFirst
-            >>> loader.get_value(u'name: foo', TakeFirst(), unicode.upper, re='name: (.+)')
-            'FOO`
-
-    .. method:: add_value(field_name, value, \*processors, \**kwargs)
-
-        Process and then add the given ``value`` for the given field.
-
-        The value is first passed through :meth:`get_value` by giving the
-        ``processors`` and ``kwargs``, and then passed through the
-        :ref:`field input processor <topics-loaders-processors>` and its result
-        appended to the data collected for that field. If the field already
-        contains collected data, the new data is added.
-
-        The given ``field_name`` can be ``None``, in which case values for
-        multiple fields may be added. And the processed value should be a dict
-        with field_name mapped to values.
-
-        Examples::
-
-            loader.add_value('name', u'Color TV')
-            loader.add_value('colours', [u'white', u'blue'])
-            loader.add_value('length', u'100')
-            loader.add_value('name', u'name: foo', TakeFirst(), re='name: (.+)')
-            loader.add_value(None, {'name': u'foo', 'sex': u'male'})
-
-    .. method:: replace_value(field_name, value, \*processors, \**kwargs)
-
-        Similar to :meth:`add_value` but replaces the collected data with the
-        new value instead of adding it.
-    .. method:: get_xpath(xpath, \*processors, \**kwargs)
-
-        Similar to :meth:`ItemLoader.get_value` but receives an XPath instead of a
-        value, which is used to extract a list of unicode strings from the
-        selector associated with this :class:`ItemLoader`.
-
-        :param xpath: the XPath to extract data from
-        :type xpath: str
-
-        :param re: a regular expression to use for extracting data from the
-            selected XPath region
-        :type re: str or compiled regex
-
-        Examples::
-
-            # HTML snippet: <p class="product-name">Color TV</p>
-            loader.get_xpath('//p[@class="product-name"]')
-            # HTML snippet: <p id="price">the price is $1200</p>
-            loader.get_xpath('//p[@id="price"]', TakeFirst(), re='the price is (.*)')
-
-    .. method:: add_xpath(field_name, xpath, \*processors, \**kwargs)
-
-        Similar to :meth:`ItemLoader.add_value` but receives an XPath instead of a
-        value, which is used to extract a list of unicode strings from the
-        selector associated with this :class:`ItemLoader`.
-
-        See :meth:`get_xpath` for ``kwargs``.
-
-        :param xpath: the XPath to extract data from
-        :type xpath: str
-
-        Examples::
-
-            # HTML snippet: <p class="product-name">Color TV</p>
-            loader.add_xpath('name', '//p[@class="product-name"]')
-            # HTML snippet: <p id="price">the price is $1200</p>
-            loader.add_xpath('price', '//p[@id="price"]', re='the price is (.*)')
-
-    .. method:: replace_xpath(field_name, xpath, \*processors, \**kwargs)
-
-        Similar to :meth:`add_xpath` but replaces collected data instead of
-        adding it.
-
-    .. method:: get_css(css, \*processors, \**kwargs)
-
-        Similar to :meth:`ItemLoader.get_value` but receives a CSS selector
-        instead of a value, which is used to extract a list of unicode strings
-        from the selector associated with this :class:`ItemLoader`.
-
-        :param css: the CSS selector to extract data from
-        :type css: str
-
-        :param re: a regular expression to use for extracting data from the
-            selected CSS region
-        :type re: str or compiled regex
-
-        Examples::
-
-            # HTML snippet: <p class="product-name">Color TV</p>
-            loader.get_css('p.product-name')
-            # HTML snippet: <p id="price">the price is $1200</p>
-            loader.get_css('p#price', TakeFirst(), re='the price is (.*)')
-
-    .. method:: add_css(field_name, css, \*processors, \**kwargs)
-
-        Similar to :meth:`ItemLoader.add_value` but receives a CSS selector
-        instead of a value, which is used to extract a list of unicode strings
-        from the selector associated with this :class:`ItemLoader`.
-
-        See :meth:`get_css` for ``kwargs``.
-
-        :param css: the CSS selector to extract data from
-        :type css: str
-
-        Examples::
-
-            # HTML snippet: <p class="product-name">Color TV</p>
-            loader.add_css('name', 'p.product-name')
-            # HTML snippet: <p id="price">the price is $1200</p>
-            loader.add_css('price', 'p#price', re='the price is (.*)')
-
-    .. method:: replace_css(field_name, css, \*processors, \**kwargs)
-
-        Similar to :meth:`add_css` but replaces collected data instead of
-        adding it.
-
-    .. method:: load_item()
-
-        Populate the item with the data collected so far, and return it. The
-        data collected is first passed through the :ref:`output processors
-        <topics-loaders-processors>` to get the final value to assign to each
-        item field.
-
-    .. method:: nested_xpath(xpath)
-
-        Create a nested loader with an xpath selector.
-        The supplied selector is applied relative to selector associated
-        with this :class:`ItemLoader`. The nested loader shares the :class:`Item`
-        with the parent :class:`ItemLoader` so calls to :meth:`add_xpath`,
-        :meth:`add_value`, :meth:`replace_value`, etc. will behave as expected.
-
-    .. method:: nested_css(css)
-
-        Create a nested loader with a css selector.
-        The supplied selector is applied relative to selector associated
-        with this :class:`ItemLoader`. The nested loader shares the :class:`Item`
-        with the parent :class:`ItemLoader` so calls to :meth:`add_xpath`,
-        :meth:`add_value`, :meth:`replace_value`, etc. will behave as expected.
-
-    .. method:: get_collected_values(field_name)
-
-        Return the collected values for the given field.
-
-    .. method:: get_output_value(field_name)
-
-        Return the collected values parsed using the output processor, for the
-        given field. This method doesn't populate or modify the item at all.
-
-    .. method:: get_input_processor(field_name)
-
-        Return the input processor for the given field.
-
-    .. method:: get_output_processor(field_name)
-
-        Return the output processor for the given field.
-
-    :class:`ItemLoader` instances have the following attributes:
-
-    .. attribute:: item
-
-        The :class:`~scrapy.item.Item` object being parsed by this Item Loader.
-
-    .. attribute:: context
-
-        The currently active :ref:`Context <topics-loaders-context>` of this
-        Item Loader.
-
-    .. attribute:: default_item_class
-
-        An Item class (or factory), used to instantiate items when not given in
-        the constructor.
-
-    .. attribute:: default_input_processor
-
-        The default input processor to use for those fields which don't specify
-        one.
-
-    .. attribute:: default_output_processor
-
-        The default output processor to use for those fields which don't specify
-        one.
-
-    .. attribute:: default_selector_class
-
-        The class used to construct the :attr:`selector` of this
-        :class:`ItemLoader`, if only a response is given in the constructor.
-        If a selector is given in the constructor this attribute is ignored.
-        This attribute is sometimes overridden in subclasses.
-
-    .. attribute:: selector
-
-        The :class:`~scrapy.selector.Selector` object to extract data from.
-        It's either the selector given in the constructor or one created from
-        the response given in the constructor using the
-        :attr:`default_selector_class`. This attribute is meant to be
-        read-only.
+.. autoclass:: scrapy.loader.ItemLoader
+    :members:
+    :inherited-members:
 
 .. _topics-loaders-nested:
 
@@ -518,33 +340,37 @@ a footer of a page that looks something like:
 Example::
 
     <footer>
-        <a class="social" href="http://facebook.com/whatever">Like Us</a>
-        <a class="social" href="http://twitter.com/whatever">Follow Us</a>
+        <a class="social" href="https://facebook.com/whatever">Like Us</a>
+        <a class="social" href="https://twitter.com/whatever">Follow Us</a>
         <a class="email" href="mailto:whatever@example.com">Email Us</a>
     </footer>
 
 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()
 
@@ -573,25 +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``):
 
-    from scrapy.loader.processors import MapCompose
+.. 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:
 
-    from scrapy.loader.processors import MapCompose
+.. 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)
 
@@ -608,156 +441,5 @@ projects. Scrapy only provides the mechanism; it doesn't impose any specific
 organization of your Loaders collection - that's up to you and your project's
 needs.
 
-.. _topics-loaders-available-processors:
-
-Available built-in processors
-=============================
-
-.. module:: scrapy.loader.processors
-   :synopsis: A collection of processors to use with Item Loaders
-
-Even though you can use any callable function as input and output processors,
-Scrapy provides some commonly used processors, which are described below. Some
-of them, like the :class:`MapCompose` (which is typically used as input
-processor) compose the output of several functions executed in order, to
-produce the final parsed value.
-
-Here is a list of all built-in processors:
-
-.. class:: Identity
-
-    The simplest processor, which doesn't do anything. It returns the original
-    values unchanged. It doesn't receive any constructor arguments, nor does it
-    accept Loader contexts.
-
-    Example::
-
-        >>> from scrapy.loader.processors import Identity
-        >>> proc = Identity()
-        >>> proc(['one', 'two', 'three'])
-        ['one', 'two', 'three']
-
-.. class:: TakeFirst
-
-    Returns the first non-null/non-empty value from the values received,
-    so it's typically used as an output processor to single-valued fields.
-    It doesn't receive any constructor arguments, nor does it accept Loader contexts.
-
-    Example::
-
-        >>> from scrapy.loader.processors import TakeFirst
-        >>> proc = TakeFirst()
-        >>> proc(['', 'one', 'two', 'three'])
-        'one'
-
-.. class:: Join(separator=u' ')
-
-    Returns the values joined with the separator given in the constructor, which
-    defaults to ``u' '``. It doesn't accept Loader contexts.
-
-    When using the default separator, this processor is equivalent to the
-    function: ``u' '.join``
-
-    Examples::
-
-        >>> from scrapy.loader.processors import Join
-        >>> proc = Join()
-        >>> proc(['one', 'two', 'three'])
-        u'one two three'
-        >>> proc = Join('<br>')
-        >>> proc(['one', 'two', 'three'])
-        u'one<br>two<br>three'
-
-.. class:: Compose(\*functions, \**default_loader_context)
-
-    A processor which is constructed from the composition of the given
-    functions. This means that each input value of this processor is passed to
-    the first function, and the result of that function is passed to the second
-    function, and so on, until the last function returns the output value of
-    this processor.
-
-    By default, stop process on ``None`` value. This behaviour can be changed by
-    passing keyword argument ``stop_on_none=False``.
-
-    Example::
-
-        >>> from scrapy.loader.processors import Compose
-        >>> proc = Compose(lambda v: v[0], str.upper)
-        >>> proc(['hello', 'world'])
-        'HELLO'
-
-    Each function can optionally receive a ``loader_context`` parameter. For
-    those which do, this processor will pass the currently active :ref:`Loader
-    context <topics-loaders-context>` through that parameter.
-
-    The keyword arguments passed in the constructor are used as the default
-    Loader context values passed to each function call. However, the final
-    Loader context values passed to functions are overridden with the currently
-    active Loader context accessible through the :meth:`ItemLoader.context`
-    attribute.
-
-.. class:: MapCompose(\*functions, \**default_loader_context)
-
-    A processor which is constructed from the composition of the given
-    functions, similar to the :class:`Compose` processor. The difference with
-    this processor is the way internal results are passed among functions,
-    which is as follows:
-
-    The input value of this processor is *iterated* and the first function is
-    applied to each element. The results of these function calls (one for each element)
-    are concatenated to construct a new iterable, which is then used to apply the
-    second function, and so on, until the last function is applied to each
-    value of the list of values collected so far. The output values of the last
-    function are concatenated together to produce the output of this processor.
-
-    Each particular function can return a value or a list of values, which is
-    flattened with the list of values returned by the same function applied to
-    the other input values. The functions can also return ``None`` in which
-    case the output of that function is ignored for further processing over the
-    chain.
-
-    This processor provides a convenient way to compose functions that only
-    work with single values (instead of iterables). For this reason the
-    :class:`MapCompose` processor is typically used as input processor, since
-    data is often extracted using the
-    :meth:`~scrapy.selector.Selector.extract` method of :ref:`selectors
-    <topics-selectors>`, which returns a list of unicode strings.
-
-    The example below should clarify how it works::
-
-        >>> def filter_world(x):
-        ...     return None if x == 'world' else x
-        ...
-        >>> from scrapy.loader.processors import MapCompose
-        >>> proc = MapCompose(filter_world, unicode.upper)
-        >>> proc([u'hello', u'world', u'this', u'is', u'scrapy'])
-        [u'HELLO, u'THIS', u'IS', u'SCRAPY']
-
-    As with the Compose processor, functions can receive Loader contexts, and
-    constructor keyword arguments are used as default context values. See
-    :class:`Compose` processor for more info.
-
-.. class:: SelectJmes(json_path)
-
-    Queries the value using the json path provided to the constructor and returns the output.
-    Requires jmespath (https://github.com/jmespath/jmespath.py) to run.
-    This processor takes only one input at a time.
-
-    Example::
-
-        >>> from scrapy.loader.processors import SelectJmes, Compose, MapCompose
-        >>> proc = SelectJmes("foo") #for direct use on lists and dictionaries
-        >>> proc({'foo': 'bar'})
-        'bar'
-        >>> proc({'foo': {'bar': 'baz'}})
-        {'bar': 'baz'}
-
-    Working with Json::
-
-        >>> import json
-        >>> proc_single_json_str = Compose(json.loads, SelectJmes("foo"))
-        >>> proc_single_json_str('{"foo": "bar"}')
-        u'bar'
-        >>> proc_json_list = Compose(json.loads, MapCompose(SelectJmes('foo')))
-        >>> proc_json_list('[{"foo":"bar"}, {"baz":"tar"}]')
-        [u'bar']
+.. _itemloaders: https://itemloaders.readthedocs.io/en/latest/
+.. _processors: https://itemloaders.readthedocs.io/en/latest/built-in-processors.html

docs/topics/logging.rst

@@ -9,8 +9,7 @@ Logging
     explicit calls to the Python standard logging. Keep reading to learn more
     about the new logging system.
 
-Scrapy uses `Python's builtin logging system
-<https://docs.python.org/2/library/logging.html>`_ for event logging. We'll
+Scrapy uses :mod:`logging` for event logging. We'll
 provide some simple examples to get you started, but for more advanced
 use-cases it's strongly suggested to read thoroughly its documentation.
 
@@ -27,7 +26,7 @@ Scrapy from scripts as described in :ref:`run-from-script`.
 Log levels
 ==========
 
-Python's builtin logging defines 5 different levels to indicate severity on a
+Python's builtin logging defines 5 different levels to indicate the severity of a
 given log message. Here are the standard ones, listed in decreasing order:
 
 1. ``logging.CRITICAL`` - for critical errors (highest severity)
@@ -40,53 +39,68 @@ 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 you need so, last example could be rewrote 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
-example, a common practice it's to create different loggers for every module).
+On top of that, you can create different "loggers" to encapsulate messages. (For
+example, a common practice is to create different loggers for every module).
 These loggers can be configured independently, and they allow hierarchical
 constructions.
 
-Last examples use the root logger behind the scenes, which is a top level
+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 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")
 
 .. seealso::
 
-    Module logging, `HowTo <https://docs.python.org/2/howto/logging.html>`_
+    Module logging, :doc:`HowTo <howto/logging>`
         Basic Logging Tutorial
 
-    Module logging, `Loggers <https://docs.python.org/2/library/logging.html#logger-objects>`_
+    Module logging, :ref:`Loggers <logger>`
         Further documentation on loggers
 
 .. _topics-logging-from-spiders:
@@ -94,34 +108,38 @@ path::
 Logging from Spiders
 ====================
 
-Scrapy provides a :data:`~scrapy.spiders.Spider.logger` within each Spider
-instance, that 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 = ['http://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 = ['http://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:
 
@@ -144,18 +162,22 @@ 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`
 * :setting:`LOG_FORMAT`
 * :setting:`LOG_DATEFORMAT`
 * :setting:`LOG_STDOUT`
+* :setting:`LOG_SHORT_NAMES`
 
-First couple of settings define a destination for log messages. If
+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
@@ -164,12 +186,14 @@ possible levels listed in :ref:`topics-logging-levels`.
 
 :setting:`LOG_FORMAT` and :setting:`LOG_DATEFORMAT` specify formatting strings
 used as layouts for all messages. Those strings can contain any placeholders
-listed in `logging's logrecord attributes docs
-<https://docs.python.org/2/library/logging.html#logrecord-attributes>`_ and
-`datetime's strftime and strptime directives
-<https://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior>`_
+listed in :ref:`logging's logrecord attributes docs <logrecord-attributes>` and
+:ref:`datetime's strftime and strptime directives <strftime-strptime-behavior>`
 respectively.
 
+If :setting:`LOG_SHORT_NAMES` is set, then the logs will not display the Scrapy
+component that prints the log. It is unset by default, hence logs contain the
+Scrapy component responsible for that log output.
+
 Command-line options
 --------------------
 
@@ -185,9 +209,114 @@ to override some of the Scrapy settings regarding logging.
 
 .. seealso::
 
-    Module `logging.handlers <https://docs.python.org/2/library/logging.handlers.html>`_
+    Module :mod:`logging.handlers`
         Further documentation on available handlers
 
+.. _custom-log-formats:
+
+Custom Log Formats
+------------------
+
+A custom log format can be set for different actions by extending
+:class:`~scrapy.logformatter.LogFormatter` class and making
+:setting:`LOG_FORMATTER` point to your new class.
+
+.. autoclass:: scrapy.logformatter.LogFormatter
+   :members:
+
+
+.. _topics-logging-advanced-customization:
+
+Advanced customization
+----------------------
+
+Because Scrapy uses stdlib logging module, you can customize logging using
+all features of stdlib logging.
+
+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 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:
+``[scrapy.spidermiddlewares.httperror]``. If you get just ``[scrapy]`` then
+:setting:`LOG_SHORT_NAMES` is likely set to True; set it to False and re-run
+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:
+
+.. code-block:: python
+
+    import logging
+    import scrapy
+
+
+    class MySpider(scrapy.Spider):
+        # ...
+        def __init__(self, *args, **kwargs):
+            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
 =======================
 
@@ -196,31 +325,27 @@ scrapy.utils.log module
 
 .. autofunction:: configure_logging
 
-    ``configure_logging`` is automatically called when using Scrapy commands,
-    but needs to be called explicitly when running custom scripts. In that
-    case, its usage is not required but it's recommended.
+    ``configure_logging`` is automatically called when using Scrapy commands
+    or :class:`~scrapy.crawler.CrawlerProcess`, but needs to be called explicitly
+    when running custom scripts using :class:`~scrapy.crawler.CrawlerRunner`.
+    In that case, its usage is not required but it's recommended.
 
-    If you plan on configuring the handlers yourself is still recommended you
-    call this function, passing `install_root_handler=False`. Bear in mind
-    there won't be any log output set by default in that case.
+    Another option when running custom scripts is to manually configure the logging.
+    To do this you can use :func:`logging.basicConfig` to set a basic root handler.
 
-    To get you started on manually configuring logging's output, you can use
-    `logging.basicConfig()`_ to set a basic root handler. This is an example
-    on how to redirect ``INFO`` or higher messages to a file::
+    Note that :class:`~scrapy.crawler.CrawlerProcess` automatically calls ``configure_logging``,
+    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:
+
+    .. code-block:: python
 
         import logging
-        from scrapy.utils.log import configure_logging
 
-        configure_logging(install_root_handler=False)
         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
     way.
-
-.. _logging.basicConfig(): https://docs.python.org/2/library/logging.html#logging.basicConfig
-
-

docs/topics/media-pipeline.rst

@@ -15,7 +15,8 @@ typically you'll either use the Files Pipeline or the Images Pipeline.
 Both pipelines implement these features:
 
 * Avoid re-downloading media that was downloaded recently
-* Specifying where to store the media (filesystem directory, Amazon S3 bucket)
+* Specifying where to store the media (filesystem directory, FTP server, Amazon S3 bucket,
+  Google Cloud Storage bucket)
 
 The Images Pipeline has a few extra functions for processing images:
 
@@ -29,7 +30,7 @@ the same media to that queue. This avoids downloading the same media more than
 once when it's shared by several items.
 
 Using the Files Pipeline
-=========================
+========================
 
 The typical workflow, when using the :class:`FilesPipeline` goes like
 this:
@@ -49,12 +50,14 @@ this:
 4. When the files are downloaded, another field (``files``) will be populated
    with the results. This field will contain a list of dicts with information
    about the downloaded files, such as the downloaded path, the original
-   scraped url (taken from the ``file_urls`` field) , and the file checksum.
+   scraped url (taken from the ``file_urls`` field), the file checksum and the file status.
    The files in the list of the ``files`` field will retain the same order of
    the original ``file_urls`` field. If some file failed downloading, an
    error will be logged and the file won't be present in the ``files`` field.
 
 
+.. _images-pipeline:
+
 Using the Images Pipeline
 =========================
 
@@ -67,44 +70,16 @@ 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/
 
 
-Usage example
-=============
-
-In order to use a media pipeline first, :ref:`enable it
-<topics-media-pipeline-enabling>`.
-
-Then, if a spider returns a dict with the URLs key ('file_urls' or
-'image_urls', for the Files or Images Pipeline respectively), the pipeline will
-put the results under respective key ('files' or images').
-
-If you prefer to use :class:`~.Item`, then define a custom item with the
-necessary fields, like in this example for Images Pipeline::
-
-    import scrapy
-
-    class MyItem(scrapy.Item):
-
-        # ... other item fields ...
-        image_urls = scrapy.Field()
-        images = scrapy.Field()
-        
-If you need something more complex and want to override the custom pipeline
-behaviour, see :ref:`topics-media-pipeline-override`.
-
 .. _topics-media-pipeline-enabling:
 
 Enabling your Media Pipeline
-=============================
+============================
 
 .. setting:: IMAGES_STORE
 .. setting:: FILES_STORE
@@ -112,14 +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.
@@ -129,38 +107,94 @@ 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:
 
-Supported Storage
-=================
+.. code-block:: python
 
-File system is currently the only officially supported storage, but there is
-also (undocumented) support for storing files in `Amazon S3`_.
+   IMAGES_STORE = "/path/to/valid/dir"
 
-.. _Amazon S3: http://aws.amazon.com/s3/
+.. _topics-file-naming:
 
-File system storage
+File Naming
+===========
+
+Default File Naming
 -------------------
 
-The files are stored using a `SHA1 hash`_ of their URLs for the file names.
+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 `SHA1 hash` is::
+Whose ``SHA-1 hash`` is::
 
     3afec3b4765f8f0a07b78f98c07b83f013567a0a
 
-Will be downloaded and stored in the following file::
+Will be downloaded and stored using your chosen :ref:`storage method <topics-supported-storage>` and the following file name::
 
-   <IMAGES_STORE>/full/3afec3b4765f8f0a07b78f98c07b83f013567a0a.jpg
+   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
+=================
+
+File system storage
+-------------------
+
+File system storage will save files to the following path::
+
+   <IMAGES_STORE>/full/<FILE_NAME>
 
 Where:
 
@@ -170,12 +204,189 @@ 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
+------------------
+
+.. versionadded:: 2.0
+
+:setting:`FILES_STORE` and :setting:`IMAGES_STORE` can point to an FTP server.
+Scrapy will automatically upload the files to the server.
+
+:setting:`FILES_STORE` and :setting:`IMAGES_STORE` should be written in one of the
+following forms::
+
+    ftp://username:password@address:port/path
+    ftp://address:port/path
+
+If ``username`` and ``password`` are not provided, they are taken from the :setting:`FTP_USER` and
+:setting:`FTP_PASSWORD` settings respectively.
+
+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
+
+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:
+
+.. 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:
+
+.. code-block:: python
+
+    IMAGES_STORE_S3_ACL = "public-read"
+
+For more information, see `canned ACLs`_ in the Amazon S3 Developer Guide.
+
+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:
+
+.. code-block:: python
+
+    AWS_ENDPOINT_URL = "http://minio.example.com:9000"
+
+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/
+
+
+.. _media-pipeline-gcs:
+
+Google Cloud Storage
+---------------------
+
+.. setting:: FILES_STORE_GCS_ACL
+.. setting:: IMAGES_STORE_GCS_ACL
+
+:setting:`FILES_STORE` and :setting:`IMAGES_STORE` can represent a Google Cloud Storage
+bucket. Scrapy will automatically upload the files to the bucket. (requires `google-cloud-storage`_ )
+
+.. _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:
+
+.. code-block:: python
+
+    IMAGES_STORE = "gs://bucket/images/"
+    GCS_PROJECT_ID = "project_id"
+
+For information about authentication, see this `documentation`_.
+
+.. _documentation: https://cloud.google.com/docs/authentication/production
+
+You can modify the Access Control List (ACL) policy used for the stored files,
+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:
+
+.. code-block:: python
+
+    IMAGES_STORE_GCS_ACL = "publicRead"
+
+For more information, see `Predefined ACLs`_ in the Google Cloud Platform Developer Guide.
+
+.. _Predefined ACLs: https://cloud.google.com/storage/docs/access-control/lists#predefined-acl
+
+Usage example
+=============
+
+.. setting:: FILES_URLS_FIELD
+.. setting:: FILES_RESULT_FIELD
+.. setting:: IMAGES_URLS_FIELD
+.. setting:: IMAGES_RESULT_FIELD
+
+In order to use a media pipeline, first :ref:`enable it
+<topics-media-pipeline-enabling>`.
+
+Then, if a spider returns an :ref:`item object <topics-items>` with the URLs
+field (``file_urls`` or ``image_urls``, for the Files or Images Pipeline
+respectively), the pipeline will put the results under the respective field
+(``files`` or ``images``).
+
+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` class:
+
+.. code-block:: python
+
+    import scrapy
+
+
+    class MyItem(scrapy.Item):
+        # ... other item fields ...
+        image_urls = scrapy.Field()
+        images = scrapy.Field()
+
+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:
+
+.. 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:
+
+.. 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`.
+
+If you have multiple image pipelines inheriting from ImagePipeline and you want
+to have different settings in different pipelines you can set setting keys
+preceded with uppercase name of your pipeline class. E.g. if your pipeline is
+called MyPipeline and you want to have custom IMAGES_URLS_FIELD you define
+setting MYPIPELINE_IMAGES_URLS_FIELD and your custom settings will be used.
+
 
 Additional features
 ===================
 
+.. _file-expiration:
+
 File expiration
-----------------
+---------------
 
 .. setting:: IMAGES_EXPIRES
 .. setting:: FILES_EXPIRES
@@ -183,14 +394,29 @@ 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:
 
-    # 90 days of delay for files expiration
-    FILES_EXPIRES = 90
+.. code-block:: python
+
+    # 120 days of delay for files expiration
+    FILES_EXPIRES = 120
 
     # 30 days of delay for images expiration
     IMAGES_EXPIRES = 30
 
+The default value for both settings is 90 days.
+
+If you have pipeline that subclasses FilesPipeline and you'd like to have
+different setting for it you can set setting keys preceded by uppercase
+class name. E.g. given pipeline class called MyPipeline you can set setting key:
+
+    MYPIPELINE_FILES_EXPIRES = 180
+
+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
@@ -201,14 +427,16 @@ images.
 
 .. setting:: IMAGES_THUMBS
 
-In order use this feature, you must set :setting:`IMAGES_THUMBS` to a dictionary
+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
@@ -221,9 +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: http://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::
 
@@ -249,10 +477,28 @@ For example::
    IMAGES_MIN_HEIGHT = 110
    IMAGES_MIN_WIDTH = 110
 
-Note: these size constraints don't affect thumbnail generation at all.
+.. note::
+    The size constraints don't affect thumbnail generation at all.
+
+It is possible to set just one size constraint or both. When setting both of
+them, only images that satisfy both minimum sizes will be saved. For the
+above example, images of sizes (105 x 105) or (105 x 200) or (200 x 105) will
+all be dropped because at least one dimension is shorter than the constraint.
 
 By default, there are no size constraints, so all images are processed.
 
+Allowing redirections
+---------------------
+
+.. setting:: MEDIA_ALLOW_REDIRECTS
+
+By default media pipelines ignore redirects, i.e. an HTTP redirection
+to a media file URL request will mean the media download is considered failed.
+
+To handle media redirections, set this setting to ``True``::
+
+    MEDIA_ALLOW_REDIRECTS = True
+
 .. _topics-media-pipeline-override:
 
 Extending the Media Pipelines
@@ -265,15 +511,60 @@ See here the methods that you can override in your custom Files Pipeline:
 
 .. class:: FilesPipeline
 
+   .. method:: file_path(self, request, response=None, info=None, *, item=None)
+
+      This method is called once per downloaded item. It returns the
+      download path of the file originating from the specified
+      :class:`response <scrapy.http.Response>`.
+
+      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>`
+
+      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``):
+
+      .. code-block:: python
+
+        from pathlib import PurePosixPath
+        from urllib.parse import urlparse
+
+        from scrapy.pipelines.files import FilesPipeline
+
+
+        class MyFilesPipeline(FilesPipeline):
+            def file_path(self, request, response=None, info=None, *, item=None):
+                return "files/" + PurePosixPath(urlparse(request.url).path).name
+
+      Similarly, you can use the ``item`` to determine the file path based on some item 
+      property.
+      
+      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):
-             for file_url in item['file_urls']:
+             adapter = ItemAdapter(item)
+             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
@@ -284,8 +575,9 @@ See here the methods that you can override in your custom Files Pipeline:
       * ``success`` is a boolean which is ``True`` if the image was downloaded
         successfully or ``False`` if it failed for some reason
 
-      * ``file_info_or_error`` is a dict containing the following keys (if success
-        is ``True``) or a `Twisted Failure`_ if there was a problem.
+      * ``file_info_or_error`` is a dict containing the following keys (if
+        success is ``True``) or a :exc:`~twisted.python.failure.Failure` if
+        there was a problem.
 
         * ``url`` - the url where the file was downloaded from. This is the url of
           the request returned from the :meth:`~get_media_requests`
@@ -296,23 +588,47 @@ See here the methods that you can override in your custom Files Pipeline:
 
         * ``checksum`` - a `MD5 hash`_ of the image contents
 
+        * ``status`` - the file status indication.
+
+          .. versionadded:: 2.2
+
+          It can be one of the following:
+
+          * ``downloaded`` - file was downloaded.
+          * ``uptodate`` - file was not downloaded, as it was downloaded recently,
+            according to the file expiration policy.
+          * ``cached`` - file was already scheduled for download, by another item
+            sharing the same file.
+
       The list of tuples received by :meth:`~item_completed` is
       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'}),
-           (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.
 
-   .. method:: FilesPipeline.item_completed(results, items, info)
+   .. method:: FilesPipeline.item_completed(results, item, info)
 
       The :meth:`FilesPipeline.item_completed` method called when all file
       requests for a single item have completed (either finished downloading, or
@@ -324,15 +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")
-              item['file_paths'] = file_paths
+              adapter = ItemAdapter(item)
+              adapter["file_paths"] = file_paths
               return item
 
       By default, the :meth:`item_completed` method returns the item.
@@ -348,6 +669,65 @@ See here the methods that you can override in your custom Images Pipeline:
     The :class:`ImagesPipeline` is an extension of the :class:`FilesPipeline`,
     customizing the field names and adding custom behavior for images.
 
+   .. method:: file_path(self, request, response=None, info=None, *, item=None)
+
+      This method is called once per downloaded item. It returns the
+      download path of the file originating from the specified
+      :class:`response <scrapy.http.Response>`.
+
+      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>`
+
+      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``):
+
+      .. code-block:: python
+
+        from pathlib import PurePosixPath
+        from urllib.parse import urlparse
+
+        from scrapy.pipelines.images import ImagesPipeline
+
+
+        class MyImagesPipeline(ImagesPipeline):
+            def file_path(self, request, response=None, info=None, *, item=None):
+                return "files/" + PurePosixPath(urlparse(request.url).path).name
+
+      Similarly, you can use the ``item`` to determine the file path based on some item 
+      property.
+      
+      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,
@@ -355,7 +735,7 @@ See here the methods that you can override in your custom Images Pipeline:
 
       Must return a Request for each image URL.
 
-   .. method:: ImagesPipeline.item_completed(results, items, info)
+   .. method:: ImagesPipeline.item_completed(results, item, info)
 
       The :meth:`ImagesPipeline.item_completed` method is called when all image
       requests for a single item have completed (either finished downloading, or
@@ -367,28 +747,41 @@ See here the methods that you can override in your custom Images Pipeline:
       By default, the :meth:`item_completed` method returns the item.
 
 
+.. _media-pipeline-example:
+
 Custom Images pipeline example
 ==============================
 
-Here is a full example of the Images Pipeline whose methods are examplified
-above::
+Here is a full example of the Images Pipeline whose methods are exemplified
+above:
+
+.. code-block:: python
 
     import scrapy
-    from scrapy.pipelines.images import ImagesPipeline
+    from itemadapter import ItemAdapter
     from scrapy.exceptions import DropItem
+    from scrapy.pipelines.images import 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")
-            item['image_paths'] = image_paths
+            adapter = ItemAdapter(item)
+            adapter["image_paths"] = image_paths
             return item
 
-.. _Twisted Failure: http://twistedmatrix.com/documents/current/api/twisted.python.failure.Failure.html
-.. _MD5 hash: http://en.wikipedia.org/wiki/MD5
+
+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:
+
+.. 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
@@ -18,31 +20,37 @@ the typical way of running Scrapy via ``scrapy crawl``.
 Remember that Scrapy is built on top of the Twisted
 asynchronous networking library, so you need to run it inside the Twisted reactor.
 
-First utility you can use to run your spiders is
+The first utility you can use to run your spiders is
 :class:`scrapy.crawler.CrawlerProcess`. This class will start a Twisted reactor
 for you, configuring the logging and setting shutdown handlers. This class is
 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({
-        'USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)'
-    })
+
+    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
 
-Make sure to check :class:`~scrapy.crawler.CrawlerProcess` documentation to get
-acquainted with its usage details.
+Define settings within dictionary in CrawlerProcess. Make sure to check :class:`~scrapy.crawler.CrawlerProcess`
+documentation to get acquainted with its usage details.
 
 If you are inside a Scrapy project there are some additional helpers you can
 use to import those components within the project. You can automatically import
@@ -53,7 +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
@@ -61,8 +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
@@ -80,27 +88,29 @@ returned by the :meth:`CrawlerRunner.crawl
 <scrapy.crawler.CrawlerRunner.crawl>` method.
 
 Here's an example of its usage, along with a callback to manually stop the
-reactor after `MySpider` has finished running.
+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:: `Twisted Reactor Overview`_.
+.. seealso:: :doc:`twisted:core/howto/reactor-basics`
 
 .. _run-multiple-spiders:
 
@@ -113,68 +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():
@@ -182,11 +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
@@ -228,28 +276,29 @@ with varying degrees of sophistication. Getting around those measures can be
 difficult and tricky, and may sometimes require special infrastructure. Please
 consider contacting `commercial support`_ if in doubt.
 
-Here are some tips to keep in mind when dealing with these kind of sites:
+Here are some tips to keep in mind when dealing with these kinds of sites:
 
 * rotate your user agent from a pool of well-known ones from browsers (google
   around to get a list of them)
 * 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`_
+  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`_
+  `Zyte Smart Proxy Manager`_
 
 If you are still unable to prevent your bot getting banned, consider contacting
 `commercial support`_.
 
 .. _Tor project: https://www.torproject.org/
-.. _commercial support: http://scrapy.org/support/
-.. _ProxyMesh: http://proxymesh.com/
-.. _Google cache: http://www.googleguide.com/cached_pages.html
+.. _commercial support: https://scrapy.org/support/
+.. _ProxyMesh: https://proxymesh.com/
+.. _Common Crawl: https://commoncrawl.org/
 .. _testspiders: https://github.com/scrapinghub/testspiders
-.. _Twisted Reactor Overview: http://twistedmatrix.com/documents/current/core/howto/reactor-basics.html
-.. _Crawlera: http://scrapinghub.com/crawlera
+.. _scrapoxy: https://scrapoxy.io/
+.. _Zyte Smart Proxy Manager: https://www.zyte.com/smart-proxy-manager/