refactor: AcceptableProtocolsContextFactory

- rename H2WrappedContextFactory to AcceptableProtocolsContextFactory
- AcceptableProtocolsContextFactory accepts an argument
acceptable_protocols which can be used to override the context factory
priority list of protocols during ALPN or NPN

scrapy/core/downloader/handlers/http2.py

@@ -3,8 +3,8 @@ from time import time
 from typing import Optional, Tuple
 from urllib.parse import urldefrag
 
-from twisted.internet.defer import Deferred
 from twisted.internet.base import ReactorBase
+from twisted.internet.defer import Deferred
 from twisted.internet.error import TimeoutError
 from twisted.web.client import URI
 

scrapy/core/http2/agent.py

@@ -97,14 +97,15 @@ class H2ConnectionPool:
 
 
 @implementer(IPolicyForHTTPS)
-class H2WrappedContextFactory:
-    def __init__(self, context_factory) -> None:
+class AcceptableProtocolsContextFactory:
+    def __init__(self, context_factory, acceptable_protocols: List[bytes]) -> None:
         verifyObject(IPolicyForHTTPS, context_factory)
         self._wrapped_context_factory = context_factory
+        self._acceptable_protocols = acceptable_protocols
 
     def creatorForNetloc(self, hostname, port) -> ClientTLSOptions:
         options = self._wrapped_context_factory.creatorForNetloc(hostname, port)
-        _setAcceptableProtocols(options._ctx, [b'h2'])
+        _setAcceptableProtocols(options._ctx, self._acceptable_protocols)
         return options
 
 
@@ -116,7 +117,7 @@ class H2Agent:
     ) -> None:
         self._reactor = reactor
         self._pool = pool
-        self._context_factory = H2WrappedContextFactory(context_factory)
+        self._context_factory = AcceptableProtocolsContextFactory(context_factory, acceptable_protocols=[b'h2'])
         self._endpoint_factory = _StandardEndpointFactory(
             self._reactor, self._context_factory,
             connect_timeout, bind_address

scrapy/core/http2/stream.py

@@ -85,7 +85,7 @@ class Stream:
         request: Request,
         protocol: "H2ClientProtocol",
         download_maxsize: int = 0,
-        download_warnsize: int = 0
+        download_warnsize: int = 0,
     ) -> None:
         """
         Arguments: