From 393ff96e45ffcb738bc9f8d3240cd4d999bd07df Mon Sep 17 00:00:00 2001
From: Andrey Rakhmatullin <wrar@wrar.name>
Date: Thu, 7 Nov 2024 21:21:17 +0500
Subject: [PATCH] Deprecate AjaxCrawlMiddleware.

---
 docs/topics/broad-crawls.rst                  | 24 -------------------
 docs/topics/downloader-middleware.rst         |  3 +--
 scrapy/downloadermiddlewares/ajaxcrawl.py     | 11 +++++++--
 ...test_downloadermiddleware_ajaxcrawlable.py |  3 +++
 4 files changed, 13 insertions(+), 28 deletions(-)

diff --git a/docs/topics/broad-crawls.rst b/docs/topics/broad-crawls.rst
index 0286c3354..248e38b61 100644
--- a/docs/topics/broad-crawls.rst
+++ b/docs/topics/broad-crawls.rst
@@ -182,30 +182,6 @@ To disable redirects use:
 
     REDIRECT_ENABLED = False
 
-Enable crawling of "Ajax Crawlable Pages"
-=========================================
-
-Some pages (up to 1%, based on empirical data from year 2013) declare
-themselves as ajax crawlable. This means they provide plain HTML
-version of content that is usually available only via AJAX.
-Pages can indicate it in two ways:
-
-1) by using ``#!`` in URL - this is the default way;
-2) by using a special meta tag - this way is used on
-   "main", "index" website pages.
-
-Scrapy handles (1) automatically; to handle (2) enable
-:ref:`AjaxCrawlMiddleware <ajaxcrawl-middleware>`:
-
-.. code-block:: python
-
-    AJAXCRAWL_ENABLED = True
-
-When doing broad crawls it's common to crawl a lot of "index" web pages;
-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.
-
 .. _broad-crawls-bfo:
 
 Crawl in BFO order
diff --git a/docs/topics/downloader-middleware.rst b/docs/topics/downloader-middleware.rst
index 1ab8f588f..ca597291f 100644
--- a/docs/topics/downloader-middleware.rst
+++ b/docs/topics/downloader-middleware.rst
@@ -1249,8 +1249,7 @@ AJAXCRAWL_ENABLED
 
 Default: ``False``
 
-Whether the AjaxCrawlMiddleware will be enabled. You may want to
-enable it for :ref:`broad crawls <topics-broad-crawls>`.
+Whether the AjaxCrawlMiddleware will be enabled.
 
 HttpProxyMiddleware settings
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/scrapy/downloadermiddlewares/ajaxcrawl.py b/scrapy/downloadermiddlewares/ajaxcrawl.py
index 166192b4f..c6a55732d 100644
--- a/scrapy/downloadermiddlewares/ajaxcrawl.py
+++ b/scrapy/downloadermiddlewares/ajaxcrawl.py
@@ -3,10 +3,11 @@ 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
+from scrapy.exceptions import NotConfigured, ScrapyDeprecationWarning
 from scrapy.http import HtmlResponse, Response
 
 if TYPE_CHECKING:
@@ -30,6 +31,13 @@ class AjaxCrawlMiddleware:
         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.
@@ -75,7 +83,6 @@ class AjaxCrawlMiddleware:
         return _has_ajaxcrawlable_meta(body)
 
 
-# XXX: move it to w3lib?
 _ajax_crawlable_re: re.Pattern[str] = re.compile(
     r'<meta\s+name=["\']fragment["\']\s+content=["\']!["\']/?>'
 )
diff --git a/tests/test_downloadermiddleware_ajaxcrawlable.py b/tests/test_downloadermiddleware_ajaxcrawlable.py
index 043dc0a12..63bd158f6 100644
--- a/tests/test_downloadermiddleware_ajaxcrawlable.py
+++ b/tests/test_downloadermiddleware_ajaxcrawlable.py
@@ -1,5 +1,7 @@
 import unittest
 
+import pytest
+
 from scrapy.downloadermiddlewares.ajaxcrawl import AjaxCrawlMiddleware
 from scrapy.http import HtmlResponse, Request, Response
 from scrapy.spiders import Spider
@@ -8,6 +10,7 @@ from scrapy.utils.test import get_crawler
 __doctests__ = ["scrapy.downloadermiddlewares.ajaxcrawl"]
 
 
+@pytest.mark.filterwarnings("ignore::scrapy.exceptions.ScrapyDeprecationWarning")
 class AjaxCrawlMiddlewareTest(unittest.TestCase):
     def setUp(self):
         crawler = get_crawler(Spider, {"AJAXCRAWL_ENABLED": True})