Add from_crawler() to components that only had from_settings().

docs/topics/email.rst

@@ -27,13 +27,13 @@ the standard ``__init__`` method:
 
     mailer = MailSender()
 
-Or you can instantiate it passing a Scrapy settings object, which will respect
-the :ref:`settings <topics-email-settings>`:
+Or you can instantiate it passing a :class:`scrapy.Crawler` instance, which
+will respect the :ref:`settings <topics-email-settings>`:
 
 .. skip: start
 .. code-block:: python
 
-    mailer = MailSender.from_settings(settings)
+    mailer = MailSender.from_crawler(crawler)
 
 And here is how to use it to send an e-mail (without attachments):
 
@@ -81,13 +81,13 @@ rest of the framework.
     :param smtpssl: enforce using a secure SSL connection
     :type smtpssl: bool
 
-    .. classmethod:: from_settings(settings)
+    .. classmethod:: from_crawler(crawler)
 
-        Instantiate using a Scrapy settings object, which will respect
-        :ref:`these Scrapy settings <topics-email-settings>`.
+        Instantiate using a :class:`scrapy.Crawler` instance, which will
+        respect :ref:`these Scrapy settings <topics-email-settings>`.
 
-        :param settings: the e-mail recipients
-        :type settings: :class:`scrapy.settings.Settings` object
+        :param crawler: the crawler
+        :type settings: :class:`scrapy.Crawler` object
 
     .. method:: send(to, subject, body, cc=None, attachs=(), mimetype='text/plain', charset=None)
 

docs/topics/request-response.rst

@@ -488,7 +488,7 @@ A request fingerprinter is a class that must implement the following method:
    :param request: request to fingerprint
    :type request: scrapy.http.Request
 
-Additionally, it may also implement the following methods:
+Additionally, it may also implement the following method:
 
 .. classmethod:: from_crawler(cls, crawler)
    :noindex:
@@ -504,13 +504,6 @@ Additionally, it may also implement the following methods:
    :param crawler: crawler that uses this request fingerprinter
    :type crawler: :class:`~scrapy.crawler.Crawler` object
 
-.. classmethod:: from_settings(cls, settings)
-
-   If present, and ``from_crawler`` is not defined, this class method is called
-   to create a request fingerprinter instance from a
-   :class:`~scrapy.settings.Settings` object. It must return a new instance of
-   the request fingerprinter.
-
 .. currentmodule:: scrapy.http
 
 The :meth:`fingerprint` method of the default request fingerprinter,

scrapy/core/downloader/contextfactory.py

@@ -21,6 +21,7 @@ from scrapy.core.downloader.tls import (
     ScrapyClientTLSOptions,
     openssl_methods,
 )
+from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.utils.misc import build_from_crawler, load_object
 
 if TYPE_CHECKING:
@@ -69,6 +70,31 @@ class ScrapyClientContextFactory(BrowserLikePolicyForHTTPS):
         method: int = SSL.SSLv23_METHOD,
         *args: Any,
         **kwargs: Any,
+    ) -> Self:
+        warnings.warn(
+            f"{cls.__name__}.from_settings() is deprecated, use from_crawler() instead.",
+            category=ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return cls._from_settings(settings, method, *args, **kwargs)
+
+    @classmethod
+    def from_crawler(
+        cls,
+        crawler: Crawler,
+        method: int = SSL.SSLv23_METHOD,
+        *args: Any,
+        **kwargs: Any,
+    ) -> Self:
+        return cls._from_settings(crawler.settings, method, *args, **kwargs)
+
+    @classmethod
+    def _from_settings(
+        cls,
+        settings: BaseSettings,
+        method: int = SSL.SSLv23_METHOD,
+        *args: Any,
+        **kwargs: Any,
     ) -> Self:
         tls_verbose_logging: bool = settings.getbool(
             "DOWNLOADER_CLIENT_TLS_VERBOSE_LOGGING"

scrapy/dupefilters.py

@@ -1,9 +1,11 @@
 from __future__ import annotations
 
 import logging
+import warnings
 from pathlib import Path
 from typing import TYPE_CHECKING
 
+from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.utils.job import job_dir
 from scrapy.utils.request import (
     RequestFingerprinter,
@@ -26,6 +28,15 @@ if TYPE_CHECKING:
 class BaseDupeFilter:
     @classmethod
     def from_settings(cls, settings: BaseSettings) -> Self:
+        warnings.warn(
+            f"{cls.__name__}.from_settings() is deprecated, use from_crawler() instead.",
+            category=ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return cls()
+
+    @classmethod
+    def from_crawler(cls, crawler: Crawler) -> Self:
         return cls()
 
     def request_seen(self, request: Request) -> bool:
@@ -72,17 +83,31 @@ class RFPDupeFilter(BaseDupeFilter):
         *,
         fingerprinter: RequestFingerprinterProtocol | None = None,
     ) -> Self:
-        debug = settings.getbool("DUPEFILTER_DEBUG")
-        return cls(job_dir(settings), debug, fingerprinter=fingerprinter)
+        warnings.warn(
+            f"{cls.__name__}.from_settings() is deprecated, use from_crawler() instead.",
+            category=ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return cls._from_settings(settings, fingerprinter=fingerprinter)
 
     @classmethod
     def from_crawler(cls, crawler: Crawler) -> Self:
         assert crawler.request_fingerprinter
-        return cls.from_settings(
+        return cls._from_settings(
             crawler.settings,
             fingerprinter=crawler.request_fingerprinter,
         )
 
+    @classmethod
+    def _from_settings(
+        cls,
+        settings: BaseSettings,
+        *,
+        fingerprinter: RequestFingerprinterProtocol | None = None,
+    ) -> Self:
+        debug = settings.getbool("DUPEFILTER_DEBUG")
+        return cls(job_dir(settings), debug, fingerprinter=fingerprinter)
+
     def request_seen(self, request: Request) -> bool:
         fp = self.request_fingerprint(request)
         if fp in self.fingerprints:

scrapy/extensions/memusage.py

@@ -48,7 +48,7 @@ class MemoryUsage:
         self.check_interval: float = crawler.settings.getfloat(
             "MEMUSAGE_CHECK_INTERVAL_SECONDS"
         )
-        self.mail: MailSender = MailSender.from_settings(crawler.settings)
+        self.mail: MailSender = MailSender.from_crawler(crawler)
         crawler.signals.connect(self.engine_started, signal=signals.engine_started)
         crawler.signals.connect(self.engine_stopped, signal=signals.engine_stopped)
 

scrapy/extensions/statsmailer.py

@@ -33,7 +33,7 @@ class StatsMailer:
         recipients: list[str] = crawler.settings.getlist("STATSMAILER_RCPTS")
         if not recipients:
             raise NotConfigured
-        mail: MailSender = MailSender.from_settings(crawler.settings)
+        mail: MailSender = MailSender.from_crawler(crawler)
         assert crawler.stats
         o = cls(crawler.stats, recipients, mail)
         crawler.signals.connect(o.spider_closed, signal=signals.spider_closed)

scrapy/mail.py

@@ -7,6 +7,7 @@ See documentation in docs/topics/email.rst
 from __future__ import annotations
 
 import logging
+import warnings
 from email import encoders as Encoders
 from email.mime.base import MIMEBase
 from email.mime.multipart import MIMEMultipart
@@ -19,6 +20,7 @@ from typing import IO, TYPE_CHECKING, Any
 from twisted.internet import ssl
 from twisted.internet.defer import Deferred
 
+from scrapy.exceptions import ScrapyDeprecationWarning
 from scrapy.utils.misc import arg_to_iter
 from scrapy.utils.python import to_bytes
 
@@ -32,6 +34,7 @@ if TYPE_CHECKING:
     # typing.Self requires Python 3.11
     from typing_extensions import Self
 
+    from scrapy.crawler import Crawler
     from scrapy.settings import BaseSettings
 
 
@@ -72,6 +75,19 @@ class MailSender:
 
     @classmethod
     def from_settings(cls, settings: BaseSettings) -> Self:
+        warnings.warn(
+            f"{cls.__name__}.from_settings() is deprecated, use from_crawler() instead.",
+            category=ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return cls._from_settings(settings)
+
+    @classmethod
+    def from_crawler(cls, crawler: Crawler) -> Self:
+        return cls._from_settings(crawler.settings)
+
+    @classmethod
+    def _from_settings(cls, settings: BaseSettings) -> Self:
         return cls(
             smtphost=settings["MAIL_HOST"],
             mailfrom=settings["MAIL_FROM"],

scrapy/spidermiddlewares/urllength.py

@@ -7,9 +7,10 @@ See documentation in docs/topics/spider-middleware.rst
 from __future__ import annotations
 
 import logging
+import warnings
 from typing import TYPE_CHECKING, Any
 
-from scrapy.exceptions import NotConfigured
+from scrapy.exceptions import NotConfigured, ScrapyDeprecationWarning
 from scrapy.http import Request, Response
 
 if TYPE_CHECKING:
@@ -19,6 +20,7 @@ if TYPE_CHECKING:
     from typing_extensions import Self
 
     from scrapy import Spider
+    from scrapy.crawler import Crawler
     from scrapy.settings import BaseSettings
 
 
@@ -31,6 +33,19 @@ class UrlLengthMiddleware:
 
     @classmethod
     def from_settings(cls, settings: BaseSettings) -> Self:
+        warnings.warn(
+            f"{cls.__name__}.from_settings() is deprecated, use from_crawler() instead.",
+            category=ScrapyDeprecationWarning,
+            stacklevel=2,
+        )
+        return cls._from_settings(settings)
+
+    @classmethod
+    def from_crawler(cls, crawler: Crawler) -> Self:
+        return cls._from_settings(crawler.settings)
+
+    @classmethod
+    def _from_settings(cls, settings: BaseSettings) -> Self:
         maxlength = settings.getint("URLLENGTH_LIMIT")
         if not maxlength:
             raise NotConfigured

tests/test_dupefilters.py

@@ -33,14 +33,6 @@ class FromCrawlerRFPDupeFilter(RFPDupeFilter):
         return df
 
 
-class FromSettingsRFPDupeFilter(RFPDupeFilter):
-    @classmethod
-    def from_settings(cls, settings, *, fingerprinter=None):
-        df = super().from_settings(settings, fingerprinter=fingerprinter)
-        df.method = "from_settings"
-        return df
-
-
 class DirectDupeFilter:
     method = "n/a"
 
@@ -56,16 +48,6 @@ class RFPDupeFilterTest(unittest.TestCase):
         self.assertTrue(scheduler.df.debug)
         self.assertEqual(scheduler.df.method, "from_crawler")
 
-    def test_df_from_settings_scheduler(self):
-        settings = {
-            "DUPEFILTER_DEBUG": True,
-            "DUPEFILTER_CLASS": FromSettingsRFPDupeFilter,
-        }
-        crawler = get_crawler(settings_dict=settings)
-        scheduler = Scheduler.from_crawler(crawler)
-        self.assertTrue(scheduler.df.debug)
-        self.assertEqual(scheduler.df.method, "from_settings")
-
     def test_df_direct_scheduler(self):
         settings = {
             "DUPEFILTER_CLASS": DirectDupeFilter,

tests/test_spidermiddleware_urllength.py

@@ -3,7 +3,6 @@ from unittest import TestCase
 from testfixtures import LogCapture
 
 from scrapy.http import Request, Response
-from scrapy.settings import Settings
 from scrapy.spidermiddlewares.urllength import UrlLengthMiddleware
 from scrapy.spiders import Spider
 from scrapy.utils.test import get_crawler
@@ -12,12 +11,10 @@ from scrapy.utils.test import get_crawler
 class TestUrlLengthMiddleware(TestCase):
     def setUp(self):
         self.maxlength = 25
-        settings = Settings({"URLLENGTH_LIMIT": self.maxlength})
-
-        crawler = get_crawler(Spider)
+        crawler = get_crawler(Spider, {"URLLENGTH_LIMIT": self.maxlength})
         self.spider = crawler._create_spider("foo")
         self.stats = crawler.stats
-        self.mw = UrlLengthMiddleware.from_settings(settings)
+        self.mw = UrlLengthMiddleware.from_crawler(crawler)
 
         self.response = Response("http://scrapytest.org")
         self.short_url_req = Request("http://scrapytest.org/")