Add support for HTTP/2

aiohttp/client.py

@@ -7,8 +7,10 @@
 import json
 import os
 import sys
+import time
 import traceback
 import warnings
+from collections import deque
 from collections.abc import (
     Awaitable,
     Callable,
@@ -232,22 +234,51 @@ async def _connect_and_send_request(req: ClientRequest) -> ClientResponse:
     connector = req._session._connector
     assert connector is not None
     try:
-        conn = await connector.connect(req, traces=req._traces, timeout=req._timeout)
+        async with connector.sem:
+            # at most just one
+            conn = await connector.connect(
+                req, traces=req._traces, timeout=req._timeout
+            )
     except asyncio.TimeoutError as exc:
         raise ConnectionTimeoutError(f"Connection timeout to host {req.url}") from exc
 
     assert conn.protocol is not None
-    conn.protocol.set_response_params(**req._response_params)
+    assert conn.protocol.transport is not None
+
+    ssl_object = conn.protocol.transport.get_extra_info("ssl_object")
+    alpn_protocol = ssl_object.selected_alpn_protocol() if ssl_object else "http/1.1"
+
+    resp = None
+    started = False
+
+    if alpn_protocol == "h2" and not connector._conns[conn._key]:
+        connector._conns[conn._key] = deque([(conn.protocol, time.monotonic())])
     try:
-        resp = await req._send(conn)
-        try:
+        # backwards compatibility
+        if alpn_protocol == "h2":
+            body = await req.body.as_bytes()
+            resp = await conn.protocol.send(  # type: ignore[attr-defined]
+                req.method,
+                req.url,
+                list(req.headers.items()),
+                body,
+            )
+
+            # we are done with the connection
+            conn._protocol = None
+        else:
+            conn.protocol.set_response_params(**req._response_params)
+            resp = await req._send(conn)
             await resp.start(conn)
-        except BaseException:
+        # h3 not implemented
+
+        started = True
+    finally:
+        if resp is not None and not started:
             resp.close()
-            raise
-    except BaseException:
-        conn.close()
-        raise
+            conn.close()
+        if resp is None:
+            conn.close()
     return resp
 
 

aiohttp/connector.py

@@ -1,5 +1,6 @@
 import asyncio
 import functools
+import os
 import random
 import socket
 import sys
@@ -51,6 +52,7 @@
     set_exception,
     set_result,
 )
+from .http_protocol import HttpDispatcherProtocol
 from .log import client_logger
 from .resolver import DefaultResolver
 
@@ -292,7 +294,7 @@ def __init__(
         ] = defaultdict(OrderedDict)
 
         self._loop = loop
-        self._factory = functools.partial(ResponseHandler, loop=loop)
+        self._factory = functools.partial(HttpDispatcherProtocol, loop=loop)
 
         # start keep-alive connection cleanup task
         self._cleanup_handle: asyncio.TimerHandle | None = None
@@ -319,6 +321,12 @@ def __init__(
         self._placeholder_future.set_result(None)
         self._cleanup_closed()
 
+        # Semaphore for HTTP/2 connections
+        # avoids duplicate connections to the
+        # same host
+        # (HTTP/2 doesn't need connection pooling to send multiple requests)
+        self.sem = asyncio.Semaphore(1)
+
     def __del__(self, _warnings: Any = warnings) -> None:
         if self._closed:
             return
@@ -856,7 +864,11 @@ def _make_ssl_context(verified: bool) -> SSLContext:
         sslcontext.verify_mode = ssl.CERT_NONE
         sslcontext.options |= ssl.OP_NO_COMPRESSION
         sslcontext.set_default_verify_paths()
-    sslcontext.set_alpn_protocols(("http/1.1",))
+
+    protocols = ["http/1.1"]
+    if os.getenv("AIOHTTP_ENABLE_EXPERIMENTAL_PROTOCOLS", False):
+        protocols += ["h2"]
+    sslcontext.set_alpn_protocols(tuple(protocols))
     return sslcontext
 
 
@@ -1403,7 +1415,8 @@ async def _start_tls_connection(
                 tls_transport
             )  # Kick the state machine of the new TLS protocol
 
-        return tls_transport, tls_proto
+        # HACK use the correct type
+        return tls_transport, tls_proto  # type: ignore[return-value]
 
     def _convert_hosts_to_addr_infos(
         self, hosts: list[ResolveResult]
@@ -1495,7 +1508,6 @@ async def _create_direct_connection(
                     bad_peer = sock.getpeername()
                     aiohappyeyeballs.remove_addr_infos(addr_infos, bad_peer)
                     continue
-
             return transp, proto
         assert last_exc is not None
         raise last_exc
@@ -1627,7 +1639,7 @@ async def _create_connection(
                 raise
             raise UnixClientConnectorError(self.path, req.connection_key, exc) from exc
 
-        return proto
+        return proto  # type: ignore[return-value]
 
 
 class NamedPipeConnector(BaseConnector):

aiohttp/helpers.py

@@ -47,7 +47,6 @@
 
 from . import hdrs
 from .log import client_logger
-from .typedefs import PathLike  # noqa
 
 if sys.version_info >= (3, 11):
     import asyncio as async_timeout