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Drop AjaxCrawlMiddleware and escape_ajax().

This commit is contained in:
Andrey Rakhmatullin 2026-04-26 16:02:30 +05:00
parent 8ecfd20fcd
commit af7dcabebb
5 changed files with 1 additions and 214 deletions
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1
docs/topics/settings.rst
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@ -809,7 +809,6 @@ Default:
"scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware": 400,
"scrapy.downloadermiddlewares.useragent.UserAgentMiddleware": 500,
"scrapy.downloadermiddlewares.retry.RetryMiddleware": 550,
"scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware": 560,
"scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware": 580,
"scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware": 590,
"scrapy.downloadermiddlewares.redirect.RedirectMiddleware": 600,

114
scrapy/downloadermiddlewares/ajaxcrawl.py
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@ -1,114 +0,0 @@
from __future__ import annotations
import logging
import re
from typing import TYPE_CHECKING
from warnings import warn
from w3lib import html
from scrapy.exceptions import NotConfigured, ScrapyDeprecationWarning
from scrapy.http import HtmlResponse, Response
from scrapy.utils.url import escape_ajax
if TYPE_CHECKING:
# typing.Self requires Python 3.11
from typing_extensions import Self
from scrapy import Request, Spider
from scrapy.crawler import Crawler
from scrapy.settings import BaseSettings
logger = logging.getLogger(__name__)
class AjaxCrawlMiddleware:
"""
Handle 'AJAX crawlable' pages marked as crawlable via meta tag.
"""
def __init__(self, settings: BaseSettings):
if not settings.getbool("AJAXCRAWL_ENABLED"):
raise NotConfigured
warn(
"scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware is deprecated"
" and will be removed in a future Scrapy version.",
ScrapyDeprecationWarning,
stacklevel=2,
)
# XXX: Google parses at least first 100k bytes; scrapy's redirect
# middleware parses first 4k. 4k turns out to be insufficient
# for this middleware, and parsing 100k could be slow.
# We use something in between (32K) by default.
self.lookup_bytes: int = settings.getint("AJAXCRAWL_MAXSIZE")
@classmethod
def from_crawler(cls, crawler: Crawler) -> Self:
return cls(crawler.settings)
def process_response(
self, request: Request, response: Response, spider: Spider
) -> Request | Response:
if not isinstance(response, HtmlResponse) or response.status != 200:
return response
if request.method != "GET":
# other HTTP methods are either not safe or don't have a body
return response
if "ajax_crawlable" in request.meta: # prevent loops
return response
if not self._has_ajax_crawlable_variant(response):
return response
ajax_crawl_request = request.replace(url=escape_ajax(request.url + "#!"))
logger.debug(
"Downloading AJAX crawlable %(ajax_crawl_request)s instead of %(request)s",
{"ajax_crawl_request": ajax_crawl_request, "request": request},
extra={"spider": spider},
)
ajax_crawl_request.meta["ajax_crawlable"] = True
return ajax_crawl_request
def _has_ajax_crawlable_variant(self, response: Response) -> bool:
"""
Return True if a page without hash fragment could be "AJAX crawlable".
"""
body = response.text[: self.lookup_bytes]
return _has_ajaxcrawlable_meta(body)
_ajax_crawlable_re: re.Pattern[str] = re.compile(
r'<meta\s+name=["\']fragment["\']\s+content=["\']!["\']/?>'
)
def _has_ajaxcrawlable_meta(text: str) -> bool:
"""
>>> _has_ajaxcrawlable_meta('<html><head><meta name="fragment" content="!"/></head><body></body></html>')
True
>>> _has_ajaxcrawlable_meta("<html><head><meta name='fragment' content='!'></head></html>")
True
>>> _has_ajaxcrawlable_meta('<html><head><!--<meta name="fragment" content="!"/>--></head><body></body></html>')
False
>>> _has_ajaxcrawlable_meta('<html></html>')
False
"""
# Stripping scripts and comments is slow (about 20x slower than
# just checking if a string is in text); this is a quick fail-fast
# path that should work for most pages.
if "fragment" not in text:
return False
if "content" not in text:
return False
text = html.remove_tags_with_content(text, ("script", "noscript"))
text = html.replace_entities(text)
text = html.remove_comments(text)
return _ajax_crawlable_re.search(text) is not None

1
scrapy/settings/default_settings.py
View File

@ -289,7 +289,6 @@ DOWNLOADER_MIDDLEWARES_BASE = {
"scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware": 400,
"scrapy.downloadermiddlewares.useragent.UserAgentMiddleware": 500,
"scrapy.downloadermiddlewares.retry.RetryMiddleware": 550,
"scrapy.downloadermiddlewares.ajaxcrawl.AjaxCrawlMiddleware": 560,
"scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware": 580,
"scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware": 590,
"scrapy.downloadermiddlewares.redirect.RedirectMiddleware": 600,

37
scrapy/utils/url.py
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@ -9,11 +9,9 @@ import re
import warnings
from importlib import import_module
from typing import TYPE_CHECKING, Any, TypeAlias
from urllib.parse import ParseResult, urldefrag, urlparse, urlunparse
from warnings import warn
from urllib.parse import ParseResult, urlparse, urlunparse
from w3lib.url import __all__ as _public_w3lib_objects
from w3lib.url import add_or_replace_parameter as _add_or_replace_parameter
from w3lib.url import any_to_uri as _any_to_uri
from w3lib.url import parse_url as _parse_url
@ -70,39 +68,6 @@ def url_has_any_extension(url: UrlT, extensions: Iterable[str]) -> bool:
return any(lowercase_path.endswith(ext) for ext in extensions)
def escape_ajax(url: str) -> str:
"""
Return the crawlable url
>>> escape_ajax("www.example.com/ajax.html#!key=value")
'www.example.com/ajax.html?_escaped_fragment_=key%3Dvalue'
>>> escape_ajax("www.example.com/ajax.html?k1=v1&k2=v2#!key=value")
'www.example.com/ajax.html?k1=v1&k2=v2&_escaped_fragment_=key%3Dvalue'
>>> escape_ajax("www.example.com/ajax.html?#!key=value")
'www.example.com/ajax.html?_escaped_fragment_=key%3Dvalue'
>>> escape_ajax("www.example.com/ajax.html#!")
'www.example.com/ajax.html?_escaped_fragment_='
URLs that are not "AJAX crawlable" (according to Google) returned as-is:
>>> escape_ajax("www.example.com/ajax.html#key=value")
'www.example.com/ajax.html#key=value'
>>> escape_ajax("www.example.com/ajax.html#")
'www.example.com/ajax.html#'
>>> escape_ajax("www.example.com/ajax.html")
'www.example.com/ajax.html'
"""
warn(
"escape_ajax() is deprecated and will be removed in a future Scrapy version.",
ScrapyDeprecationWarning,
stacklevel=2,
)
defrag, frag = urldefrag(url)
if not frag.startswith("!"):
return url
return _add_or_replace_parameter(defrag, "_escaped_fragment_", frag[1:])
def add_http_if_no_scheme(url: str) -> str:
"""Add http as the default scheme if it is missing from the url."""
match = re.match(r"^\w+://", url, flags=re.IGNORECASE)

62
tests/test_downloadermiddleware_ajaxcrawlable.py
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@ -1,62 +0,0 @@
import pytest
from scrapy.downloadermiddlewares.ajaxcrawl import AjaxCrawlMiddleware
from scrapy.http import HtmlResponse, Request, Response
from scrapy.spiders import Spider
from scrapy.utils.test import get_crawler
@pytest.mark.filterwarnings("ignore::scrapy.exceptions.ScrapyDeprecationWarning")
class TestAjaxCrawlMiddleware:
def setup_method(self):
crawler = get_crawler(Spider, {"AJAXCRAWL_ENABLED": True})
self.spider = crawler._create_spider("foo")
self.mw = AjaxCrawlMiddleware.from_crawler(crawler)
def _ajaxcrawlable_body(self):
return b'<html><head><meta name="fragment" content="!"/></head><body></body></html>'
def _req_resp(self, url, req_kwargs=None, resp_kwargs=None):
req = Request(url, **(req_kwargs or {}))
resp = HtmlResponse(url, request=req, **(resp_kwargs or {}))
return req, resp
def test_non_get(self):
req, resp = self._req_resp("http://example.com/", {"method": "HEAD"})
resp2 = self.mw.process_response(req, resp, self.spider)
assert resp == resp2
def test_binary_response(self):
req = Request("http://example.com/")
resp = Response("http://example.com/", body=b"foobar\x00\x01\x02", request=req)
resp2 = self.mw.process_response(req, resp, self.spider)
assert resp is resp2
def test_ajaxcrawl(self):
req, resp = self._req_resp(
"http://example.com/",
{"meta": {"foo": "bar"}},
{"body": self._ajaxcrawlable_body()},
)
req2 = self.mw.process_response(req, resp, self.spider)
assert req2.url == "http://example.com/?_escaped_fragment_="
assert req2.meta["foo"] == "bar"
def test_ajaxcrawl_loop(self):
req, resp = self._req_resp(
"http://example.com/", {}, {"body": self._ajaxcrawlable_body()}
)
req2 = self.mw.process_response(req, resp, self.spider)
resp2 = HtmlResponse(req2.url, body=resp.body, request=req2)
resp3 = self.mw.process_response(req2, resp2, self.spider)
assert isinstance(resp3, HtmlResponse), (resp3.__class__, resp3)
assert resp3.request.url == "http://example.com/?_escaped_fragment_="
assert resp3 is resp2
def test_noncrawlable_body(self):
req, resp = self._req_resp(
"http://example.com/", {}, {"body": b"<html></html>"}
)
resp2 = self.mw.process_response(req, resp, self.spider)
assert resp is resp2