Загрузить файлы в «venv/Lib/site-packages/uvicorn/protocols/http»

venv/Lib/site-packages/uvicorn/protocols/http/auto.py

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+from __future__ import annotations
+
+import asyncio
+
+AutoHTTPProtocol: type[asyncio.Protocol]
+try:
+    import httptools  # noqa
+except ImportError:  # pragma: no cover
+    from uvicorn.protocols.http.h11_impl import H11Protocol
+
+    AutoHTTPProtocol = H11Protocol
+else:  # pragma: no cover
+    from uvicorn.protocols.http.httptools_impl import HttpToolsProtocol
+
+    AutoHTTPProtocol = HttpToolsProtocol

venv/Lib/site-packages/uvicorn/protocols/http/flow_control.py

@@ -0,0 +1,54 @@
+import asyncio
+
+from uvicorn._types import ASGIReceiveCallable, ASGISendCallable, Scope
+
+CLOSE_HEADER = (b"connection", b"close")
+
+HIGH_WATER_LIMIT = 65536
+
+
+class FlowControl:
+    def __init__(self, transport: asyncio.Transport) -> None:
+        self._transport = transport
+        self.read_paused = False
+        self.write_paused = False
+        self._is_writable_event = asyncio.Event()
+        self._is_writable_event.set()
+
+    async def drain(self) -> None:
+        await self._is_writable_event.wait()  # pragma: full coverage
+
+    def pause_reading(self) -> None:
+        if not self.read_paused:
+            self.read_paused = True
+            self._transport.pause_reading()
+
+    def resume_reading(self) -> None:
+        if self.read_paused:
+            self.read_paused = False
+            self._transport.resume_reading()
+
+    def pause_writing(self) -> None:
+        if not self.write_paused:  # pragma: full coverage
+            self.write_paused = True
+            self._is_writable_event.clear()
+
+    def resume_writing(self) -> None:
+        if self.write_paused:  # pragma: full coverage
+            self.write_paused = False
+            self._is_writable_event.set()
+
+
+async def service_unavailable(scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable) -> None:
+    await send(
+        {
+            "type": "http.response.start",
+            "status": 503,
+            "headers": [
+                (b"content-type", b"text/plain; charset=utf-8"),
+                (b"content-length", b"19"),
+                (b"connection", b"close"),
+            ],
+        }
+    )
+    await send({"type": "http.response.body", "body": b"Service Unavailable", "more_body": False})

venv/Lib/site-packages/uvicorn/protocols/http/h11_impl.py

@@ -0,0 +1,544 @@
+from __future__ import annotations
+
+import asyncio
+import contextvars
+import http
+import logging
+import sys
+from collections.abc import Callable
+from typing import Any, Literal
+from urllib.parse import unquote
+
+import h11
+from h11._connection import DEFAULT_MAX_INCOMPLETE_EVENT_SIZE
+
+from uvicorn._types import (
+    ASGI3Application,
+    ASGIReceiveEvent,
+    ASGISendEvent,
+    HTTPRequestEvent,
+    HTTPResponseBodyEvent,
+    HTTPResponseStartEvent,
+    HTTPScope,
+)
+from uvicorn.config import Config
+from uvicorn.logging import TRACE_LOG_LEVEL
+from uvicorn.protocols.http.flow_control import CLOSE_HEADER, HIGH_WATER_LIMIT, FlowControl, service_unavailable
+from uvicorn.protocols.utils import get_client_addr, get_local_addr, get_path_with_query_string, get_remote_addr, is_ssl
+from uvicorn.server import ServerState
+
+
+def _get_status_phrase(status_code: int) -> bytes:
+    try:
+        return http.HTTPStatus(status_code).phrase.encode()
+    except ValueError:
+        return b""
+
+
+STATUS_PHRASES = {status_code: _get_status_phrase(status_code) for status_code in range(100, 600)}
+
+
+class H11Protocol(asyncio.Protocol):
+    def __init__(
+        self,
+        config: Config,
+        server_state: ServerState,
+        app_state: dict[str, Any],
+        _loop: asyncio.AbstractEventLoop | None = None,
+    ) -> None:
+        if not config.loaded:
+            config.load()
+
+        self.config = config
+        self.app = config.loaded_app
+        self.loop = _loop or asyncio.get_event_loop()
+        self.logger = logging.getLogger("uvicorn.error")
+        self.access_logger = logging.getLogger("uvicorn.access")
+        self.access_log = self.access_logger.hasHandlers()
+        self.conn = h11.Connection(
+            h11.SERVER,
+            config.h11_max_incomplete_event_size
+            if config.h11_max_incomplete_event_size is not None
+            else DEFAULT_MAX_INCOMPLETE_EVENT_SIZE,
+        )
+        self.ws_protocol_class = config.ws_protocol_class
+        self.root_path = config.root_path
+        self.limit_concurrency = config.limit_concurrency
+        self.app_state = app_state
+
+        # Timeouts
+        self.timeout_keep_alive_task: asyncio.TimerHandle | None = None
+        self.timeout_keep_alive = config.timeout_keep_alive
+
+        # Shared server state
+        self.server_state = server_state
+        self.connections = server_state.connections
+        self.tasks = server_state.tasks
+
+        # Per-connection state
+        self.transport: asyncio.Transport = None  # type: ignore[assignment]
+        self.flow: FlowControl = None  # type: ignore[assignment]
+        self.server: tuple[str, int | None] | None = None
+        self.client: tuple[str, int] | None = None
+        self.scheme: Literal["http", "https"] | None = None
+
+        # Per-request state
+        self.scope: HTTPScope = None  # type: ignore[assignment]
+        self.headers: list[tuple[bytes, bytes]] = None  # type: ignore[assignment]
+        self.cycle: RequestResponseCycle = None  # type: ignore[assignment]
+
+    # Protocol interface
+    def connection_made(  # type: ignore[override]
+        self, transport: asyncio.Transport
+    ) -> None:
+        self.connections.add(self)
+
+        self.transport = transport
+        self.flow = FlowControl(transport)
+        self.server = get_local_addr(transport)
+        self.client = get_remote_addr(transport)
+        self.scheme = "https" if is_ssl(transport) else "http"
+
+        if self.logger.level <= TRACE_LOG_LEVEL:
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sHTTP connection made", prefix)
+
+    def connection_lost(self, exc: Exception | None) -> None:
+        self.connections.discard(self)
+
+        if self.logger.level <= TRACE_LOG_LEVEL:
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sHTTP connection lost", prefix)
+
+        if self.cycle and not self.cycle.response_complete:
+            self.cycle.disconnected = True
+        if self.conn.our_state != h11.ERROR:
+            event = h11.ConnectionClosed()
+            try:
+                self.conn.send(event)
+            except h11.LocalProtocolError:
+                # Premature client disconnect
+                pass
+
+        if self.cycle is not None:
+            self.cycle.message_event.set()
+        if self.flow is not None:
+            self.flow.resume_writing()
+        if exc is None:
+            self.transport.close()
+            self._unset_keepalive_if_required()
+
+    def eof_received(self) -> None:
+        pass
+
+    def _unset_keepalive_if_required(self) -> None:
+        if self.timeout_keep_alive_task is not None:
+            self.timeout_keep_alive_task.cancel()
+            self.timeout_keep_alive_task = None
+
+    def _get_upgrade(self) -> bytes | None:
+        connection = []
+        upgrade = None
+        for name, value in self.headers:
+            if name == b"connection":
+                connection = [token.lower().strip() for token in value.split(b",")]
+            if name == b"upgrade":
+                upgrade = value.lower()
+        if b"upgrade" in connection:
+            return upgrade
+        return None
+
+    def _should_upgrade_to_ws(self) -> bool:
+        if self.ws_protocol_class is None:
+            return False
+        return True
+
+    def _unsupported_upgrade_warning(self) -> None:
+        msg = "Unsupported upgrade request."
+        self.logger.warning(msg)
+        if not self._should_upgrade_to_ws():
+            msg = "No supported WebSocket library detected. Please use \"pip install 'uvicorn[standard]'\", or install 'websockets' or 'wsproto' manually."  # noqa: E501
+            self.logger.warning(msg)
+
+    def _should_upgrade(self) -> bool:
+        upgrade = self._get_upgrade()
+        if upgrade == b"websocket" and self._should_upgrade_to_ws():
+            return True
+        if upgrade is not None:
+            self._unsupported_upgrade_warning()
+        return False
+
+    def data_received(self, data: bytes) -> None:
+        self._unset_keepalive_if_required()
+
+        self.conn.receive_data(data)
+        self.handle_events()
+
+    def handle_events(self) -> None:
+        while True:
+            try:
+                event = self.conn.next_event()
+            except h11.RemoteProtocolError:
+                msg = "Invalid HTTP request received."
+                self.logger.warning(msg)
+                self.send_400_response(msg)
+                return
+
+            if event is h11.NEED_DATA:
+                break
+
+            elif event is h11.PAUSED:
+                # This case can occur in HTTP pipelining, so we need to
+                # stop reading any more data, and ensure that at the end
+                # of the active request/response cycle we handle any
+                # events that have been buffered up.
+                self.flow.pause_reading()
+                break
+
+            elif isinstance(event, h11.Request):
+                self.headers = [(key.lower(), value) for key, value in event.headers]
+                raw_path, _, query_string = event.target.partition(b"?")
+                path = unquote(raw_path.decode("ascii"))
+                full_path = self.root_path + path
+                full_raw_path = self.root_path.encode("ascii") + raw_path
+                self.scope = {
+                    "type": "http",
+                    "asgi": {"version": self.config.asgi_version, "spec_version": "2.3"},
+                    "http_version": event.http_version.decode("ascii"),
+                    "server": self.server,
+                    "client": self.client,
+                    "scheme": self.scheme,  # type: ignore[typeddict-item]
+                    "method": event.method.decode("ascii"),
+                    "root_path": self.root_path,
+                    "path": full_path,
+                    "raw_path": full_raw_path,
+                    "query_string": query_string,
+                    "headers": self.headers,
+                    "state": self.app_state.copy(),
+                }
+                if self._should_upgrade():
+                    self.handle_websocket_upgrade(event)
+                    return
+
+                # Handle 503 responses when 'limit_concurrency' is exceeded.
+                if self.limit_concurrency is not None and (
+                    len(self.connections) >= self.limit_concurrency or len(self.tasks) >= self.limit_concurrency
+                ):
+                    app = service_unavailable
+                    message = "Exceeded concurrency limit."
+                    self.logger.warning(message)
+                else:
+                    app = self.app
+
+                # When starting to process a request, disable the keep-alive
+                # timeout. Normally we disable this when receiving data from
+                # client and set back when finishing processing its request.
+                # However, for pipelined requests processing finishes after
+                # already receiving the next request and thus the timer may
+                # be set here, which we don't want.
+                self._unset_keepalive_if_required()
+
+                self.cycle = RequestResponseCycle(
+                    scope=self.scope,
+                    conn=self.conn,
+                    transport=self.transport,
+                    flow=self.flow,
+                    logger=self.logger,
+                    access_logger=self.access_logger,
+                    access_log=self.access_log,
+                    default_headers=self.server_state.default_headers,
+                    message_event=asyncio.Event(),
+                    on_response=self.on_response_complete,
+                )
+                if self.config.reset_contextvars:
+                    # Opt-in workaround for https://github.com/python/cpython/issues/140947:
+                    # asyncio can leak context vars between tasks. Hides context set in the
+                    # lifespan or by external instrumentation.
+                    if sys.version_info >= (3, 11):  # pragma: py-lt-311
+                        task = self.loop.create_task(self.cycle.run_asgi(app), context=contextvars.Context())
+                    else:  # pragma: py-gte-311
+                        task = contextvars.Context().run(self.loop.create_task, self.cycle.run_asgi(app))
+                else:
+                    task = self.loop.create_task(self.cycle.run_asgi(app))
+                task.add_done_callback(self.tasks.discard)
+                self.tasks.add(task)
+
+            elif isinstance(event, h11.Data):
+                if self.conn.our_state is h11.DONE:
+                    continue
+                self.cycle.body += event.data
+                if len(self.cycle.body) > HIGH_WATER_LIMIT:
+                    self.flow.pause_reading()
+                self.cycle.message_event.set()
+
+            elif isinstance(event, h11.EndOfMessage):
+                if self.conn.our_state is h11.DONE:
+                    self.transport.resume_reading()
+                    self.conn.start_next_cycle()
+                    continue
+                self.cycle.more_body = False
+                self.cycle.message_event.set()
+                if self.conn.their_state == h11.MUST_CLOSE:
+                    break
+
+    def handle_websocket_upgrade(self, event: h11.Request) -> None:
+        if self.logger.level <= TRACE_LOG_LEVEL:  # pragma: full coverage
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sUpgrading to WebSocket", prefix)
+
+        self.connections.discard(self)
+        output = [event.method, b" ", event.target, b" HTTP/1.1\r\n"]
+        for name, value in self.headers:
+            output += [name, b": ", value, b"\r\n"]
+        output.append(b"\r\n")
+        protocol = self.ws_protocol_class(  # type: ignore[call-arg, misc]
+            config=self.config,
+            server_state=self.server_state,
+            app_state=self.app_state,
+        )
+        protocol.connection_made(self.transport)
+        protocol.data_received(b"".join(output))
+        self.transport.set_protocol(protocol)
+
+    def send_400_response(self, msg: str) -> None:
+        reason = STATUS_PHRASES[400]
+        headers: list[tuple[bytes, bytes]] = [
+            (b"content-type", b"text/plain; charset=utf-8"),
+            (b"connection", b"close"),
+        ]
+        event = h11.Response(status_code=400, headers=headers, reason=reason)
+        output = self.conn.send(event)
+        self.transport.write(output)
+
+        output = self.conn.send(event=h11.Data(data=msg.encode("ascii")))
+        self.transport.write(output)
+
+        output = self.conn.send(event=h11.EndOfMessage())
+        self.transport.write(output)
+
+        self.transport.close()
+
+    def on_response_complete(self) -> None:
+        self.server_state.total_requests += 1
+
+        if self.transport.is_closing():
+            return
+
+        # Set a short Keep-Alive timeout.
+        self._unset_keepalive_if_required()
+
+        self.timeout_keep_alive_task = self.loop.call_later(self.timeout_keep_alive, self.timeout_keep_alive_handler)
+
+        # Unpause data reads if needed.
+        self.flow.resume_reading()
+
+        # Unblock any pipelined events.
+        if self.conn.our_state is h11.DONE and self.conn.their_state is h11.DONE:
+            self.conn.start_next_cycle()
+            self.handle_events()
+
+    def shutdown(self) -> None:
+        """
+        Called by the server to commence a graceful shutdown.
+        """
+        if self.cycle is None or self.cycle.response_complete:
+            event = h11.ConnectionClosed()
+            self.conn.send(event)
+            self.transport.close()
+        else:
+            self.cycle.keep_alive = False
+
+    def pause_writing(self) -> None:
+        """
+        Called by the transport when the write buffer exceeds the high water mark.
+        """
+        self.flow.pause_writing()  # pragma: full coverage
+
+    def resume_writing(self) -> None:
+        """
+        Called by the transport when the write buffer drops below the low water mark.
+        """
+        self.flow.resume_writing()  # pragma: full coverage
+
+    def timeout_keep_alive_handler(self) -> None:
+        """
+        Called on a keep-alive connection if no new data is received after a short
+        delay.
+        """
+        if not self.transport.is_closing():
+            event = h11.ConnectionClosed()
+            self.conn.send(event)
+            self.transport.close()
+
+
+class RequestResponseCycle:
+    def __init__(
+        self,
+        scope: HTTPScope,
+        conn: h11.Connection,
+        transport: asyncio.Transport,
+        flow: FlowControl,
+        logger: logging.Logger,
+        access_logger: logging.Logger,
+        access_log: bool,
+        default_headers: list[tuple[bytes, bytes]],
+        message_event: asyncio.Event,
+        on_response: Callable[..., None],
+    ) -> None:
+        self.scope = scope
+        self.conn = conn
+        self.transport = transport
+        self.flow = flow
+        self.logger = logger
+        self.access_logger = access_logger
+        self.access_log = access_log
+        self.default_headers = default_headers
+        self.message_event = message_event
+        self.on_response = on_response
+
+        # Connection state
+        self.disconnected = False
+        self.keep_alive = True
+        self.waiting_for_100_continue = conn.they_are_waiting_for_100_continue
+
+        # Request state
+        self.body = bytearray()
+        self.more_body = True
+
+        # Response state
+        self.response_started = False
+        self.response_complete = False
+
+    # ASGI exception wrapper
+    async def run_asgi(self, app: ASGI3Application) -> None:
+        try:
+            result = await app(  # type: ignore[func-returns-value]
+                self.scope, self.receive, self.send
+            )
+        except BaseException as exc:
+            msg = "Exception in ASGI application\n"
+            self.logger.error(msg, exc_info=exc)
+            if not self.response_started:
+                await self.send_500_response()
+            else:
+                self.transport.close()
+        else:
+            if result is not None:
+                msg = "ASGI callable should return None, but returned '%s'."
+                self.logger.error(msg, result)
+                self.transport.close()
+            elif not self.response_started and not self.disconnected:
+                msg = "ASGI callable returned without starting response."
+                self.logger.error(msg)
+                await self.send_500_response()
+            elif not self.response_complete and not self.disconnected:
+                msg = "ASGI callable returned without completing response."
+                self.logger.error(msg)
+                self.transport.close()
+        finally:
+            self.on_response = lambda: None
+
+    async def send_500_response(self) -> None:
+        response_start_event: HTTPResponseStartEvent = {
+            "type": "http.response.start",
+            "status": 500,
+            "headers": [
+                (b"content-type", b"text/plain; charset=utf-8"),
+                (b"connection", b"close"),
+            ],
+        }
+        await self.send(response_start_event)
+        response_body_event: HTTPResponseBodyEvent = {
+            "type": "http.response.body",
+            "body": b"Internal Server Error",
+            "more_body": False,
+        }
+        await self.send(response_body_event)
+
+    # ASGI interface
+    async def send(self, message: ASGISendEvent) -> None:
+        if self.flow.write_paused and not self.disconnected:
+            await self.flow.drain()  # pragma: full coverage
+
+        if self.disconnected:
+            return  # pragma: full coverage
+
+        if not self.response_started:
+            # Sending response status line and headers
+            if message["type"] != "http.response.start":
+                raise RuntimeError(f"Expected ASGI message 'http.response.start', but got '{message['type']}'.")
+
+            self.response_started = True
+            self.waiting_for_100_continue = False
+
+            status = message["status"]
+            headers = self.default_headers + list(message.get("headers", []))
+
+            if CLOSE_HEADER in self.scope["headers"] and CLOSE_HEADER not in headers:
+                headers = headers + [CLOSE_HEADER]
+
+            if self.access_log:
+                self.access_logger.info(
+                    '%s - "%s %s HTTP/%s" %d',
+                    get_client_addr(self.scope),
+                    self.scope["method"],
+                    get_path_with_query_string(self.scope),
+                    self.scope["http_version"],
+                    status,
+                )
+
+            # Write response status line and headers
+            reason = STATUS_PHRASES[status]
+            response = h11.Response(status_code=status, headers=headers, reason=reason)
+            output = self.conn.send(event=response)
+            self.transport.write(output)
+
+        elif not self.response_complete:
+            # Sending response body
+            if message["type"] != "http.response.body":
+                raise RuntimeError(f"Expected ASGI message 'http.response.body', but got '{message['type']}'.")
+
+            body = message.get("body", b"")
+            more_body = message.get("more_body", False)
+
+            # Write response body
+            data = b"" if self.scope["method"] == "HEAD" else body
+            output = self.conn.send(event=h11.Data(data=data))
+            self.transport.write(output)
+
+            # Handle response completion
+            if not more_body:
+                self.response_complete = True
+                self.message_event.set()
+                output = self.conn.send(event=h11.EndOfMessage())
+                self.transport.write(output)
+
+        else:
+            # Response already sent
+            raise RuntimeError(f"Unexpected ASGI message '{message['type']}' sent, after response already completed.")
+
+        if self.response_complete:
+            if self.conn.our_state is h11.MUST_CLOSE or not self.keep_alive:
+                self.conn.send(event=h11.ConnectionClosed())
+                self.transport.close()
+            self.on_response()
+
+    async def receive(self) -> ASGIReceiveEvent:
+        if self.waiting_for_100_continue and not self.transport.is_closing():
+            headers: list[tuple[str, str]] = []
+            event = h11.InformationalResponse(status_code=100, headers=headers, reason="Continue")
+            output = self.conn.send(event=event)
+            self.transport.write(output)
+            self.waiting_for_100_continue = False
+
+        if not self.disconnected and not self.response_complete:
+            self.flow.resume_reading()
+            await self.message_event.wait()
+            self.message_event.clear()
+
+        if self.disconnected or self.response_complete:
+            return {"type": "http.disconnect"}
+
+        message: HTTPRequestEvent = {"type": "http.request", "body": bytes(self.body), "more_body": self.more_body}
+        self.body = bytearray()
+        return message

venv/Lib/site-packages/uvicorn/protocols/http/httptools_impl.py

@@ -0,0 +1,576 @@
+from __future__ import annotations
+
+import asyncio
+import contextvars
+import http
+import logging
+import re
+import sys
+import urllib
+from asyncio.events import TimerHandle
+from collections import deque
+from collections.abc import Callable
+from typing import Any, Literal
+
+import httptools
+
+from uvicorn._types import (
+    ASGI3Application,
+    ASGIReceiveEvent,
+    ASGISendEvent,
+    HTTPRequestEvent,
+    HTTPScope,
+)
+from uvicorn.config import Config
+from uvicorn.logging import TRACE_LOG_LEVEL
+from uvicorn.protocols.http.flow_control import CLOSE_HEADER, HIGH_WATER_LIMIT, FlowControl, service_unavailable
+from uvicorn.protocols.utils import get_client_addr, get_local_addr, get_path_with_query_string, get_remote_addr, is_ssl
+from uvicorn.server import ServerState
+
+HEADER_RE = re.compile(b'[\x00-\x1f\x7f()<>@,;:\\[\\]={} \t\\\\"]')
+HEADER_VALUE_RE = re.compile(b"[\x00-\x08\x0a-\x1f\x7f]")
+
+
+def _get_status_line(status_code: int) -> bytes:
+    try:
+        phrase = http.HTTPStatus(status_code).phrase.encode()
+    except ValueError:
+        phrase = b""
+    return b"".join([b"HTTP/1.1 ", str(status_code).encode(), b" ", phrase, b"\r\n"])
+
+
+STATUS_LINE = {status_code: _get_status_line(status_code) for status_code in range(100, 600)}
+
+
+class HttpToolsProtocol(asyncio.Protocol):
+    def __init__(
+        self,
+        config: Config,
+        server_state: ServerState,
+        app_state: dict[str, Any],
+        _loop: asyncio.AbstractEventLoop | None = None,
+    ) -> None:
+        if not config.loaded:
+            config.load()
+
+        self.config = config
+        self.app = config.loaded_app
+        self.loop = _loop or asyncio.get_event_loop()
+        self.logger = logging.getLogger("uvicorn.error")
+        self.access_logger = logging.getLogger("uvicorn.access")
+        self.access_log = self.access_logger.hasHandlers()
+        self.parser = httptools.HttpRequestParser(self)
+
+        try:
+            # Enable dangerous leniencies to allow server to a response on the first request from a pipelined request.
+            self.parser.set_dangerous_leniencies(lenient_data_after_close=True)
+        except AttributeError:  # pragma: no cover
+            # httptools < 0.6.3
+            pass
+
+        self.ws_protocol_class = config.ws_protocol_class
+        self.root_path = config.root_path
+        self.limit_concurrency = config.limit_concurrency
+        self.app_state = app_state
+
+        # Timeouts
+        self.timeout_keep_alive_task: TimerHandle | None = None
+        self.timeout_keep_alive = config.timeout_keep_alive
+
+        # Global state
+        self.server_state = server_state
+        self.connections = server_state.connections
+        self.tasks = server_state.tasks
+
+        # Per-connection state
+        self.transport: asyncio.Transport = None  # type: ignore[assignment]
+        self.flow: FlowControl = None  # type: ignore[assignment]
+        self.server: tuple[str, int | None] | None = None
+        self.client: tuple[str, int] | None = None
+        self.scheme: Literal["http", "https"] | None = None
+        self.pipeline: deque[tuple[RequestResponseCycle, ASGI3Application]] = deque()
+
+        # Per-request state
+        self.scope: HTTPScope = None  # type: ignore[assignment]
+        self.headers: list[tuple[bytes, bytes]] = None  # type: ignore[assignment]
+        self.expect_100_continue = False
+        self.cycle: RequestResponseCycle = None  # type: ignore[assignment]
+
+    # Protocol interface
+    def connection_made(  # type: ignore[override]
+        self, transport: asyncio.Transport
+    ) -> None:
+        self.connections.add(self)
+
+        self.transport = transport
+        self.flow = FlowControl(transport)
+        self.server = get_local_addr(transport)
+        self.client = get_remote_addr(transport)
+        self.scheme = "https" if is_ssl(transport) else "http"
+
+        if self.logger.level <= TRACE_LOG_LEVEL:
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sHTTP connection made", prefix)
+
+    def connection_lost(self, exc: Exception | None) -> None:
+        self.connections.discard(self)
+
+        if self.logger.level <= TRACE_LOG_LEVEL:
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sHTTP connection lost", prefix)
+
+        if self.cycle and not self.cycle.response_complete:
+            self.cycle.disconnected = True
+        if self.cycle is not None:
+            self.cycle.message_event.set()
+        if self.flow is not None:
+            self.flow.resume_writing()
+        if exc is None:
+            self.transport.close()
+            self._unset_keepalive_if_required()
+
+        self.parser = None  # type: ignore[assignment]
+
+    def eof_received(self) -> None:
+        pass
+
+    def _unset_keepalive_if_required(self) -> None:
+        if self.timeout_keep_alive_task is not None:
+            self.timeout_keep_alive_task.cancel()
+            self.timeout_keep_alive_task = None
+
+    def _get_upgrade(self) -> bytes | None:
+        connection = []
+        upgrade = None
+        for name, value in self.headers:
+            if name == b"connection":
+                connection = [token.lower().strip() for token in value.split(b",")]
+            if name == b"upgrade":
+                upgrade = value.lower()
+        if b"upgrade" in connection:
+            return upgrade
+        return None  # pragma: full coverage
+
+    def _should_upgrade_to_ws(self) -> bool:
+        if self.ws_protocol_class is None:
+            return False
+        return True
+
+    def _unsupported_upgrade_warning(self) -> None:
+        self.logger.warning("Unsupported upgrade request.")
+        if not self._should_upgrade_to_ws():
+            msg = "No supported WebSocket library detected. Please use \"pip install 'uvicorn[standard]'\", or install 'websockets' or 'wsproto' manually."  # noqa: E501
+            self.logger.warning(msg)
+
+    def _should_upgrade(self) -> bool:
+        upgrade = self._get_upgrade()
+        return upgrade == b"websocket" and self._should_upgrade_to_ws()
+
+    def data_received(self, data: bytes) -> None:
+        self._unset_keepalive_if_required()
+
+        try:
+            self.parser.feed_data(data)
+        except httptools.HttpParserError:
+            msg = "Invalid HTTP request received."
+            self.logger.warning(msg)
+            self.send_400_response(msg)
+            return
+        except httptools.HttpParserUpgrade:
+            if self._should_upgrade():
+                self.handle_websocket_upgrade()
+            else:
+                self._unsupported_upgrade_warning()
+
+    def handle_websocket_upgrade(self) -> None:
+        if self.logger.level <= TRACE_LOG_LEVEL:
+            prefix = "%s:%d - " % self.client if self.client else ""
+            self.logger.log(TRACE_LOG_LEVEL, "%sUpgrading to WebSocket", prefix)
+
+        self.connections.discard(self)
+        method = self.scope["method"].encode()
+        output = [method, b" ", self.url, b" HTTP/1.1\r\n"]
+        for name, value in self.scope["headers"]:
+            output += [name, b": ", value, b"\r\n"]
+        output.append(b"\r\n")
+        protocol = self.ws_protocol_class(  # type: ignore[call-arg, misc]
+            config=self.config,
+            server_state=self.server_state,
+            app_state=self.app_state,
+        )
+        protocol.connection_made(self.transport)
+        protocol.data_received(b"".join(output))
+        self.transport.set_protocol(protocol)
+
+    def send_400_response(self, msg: str) -> None:
+        content = [STATUS_LINE[400]]
+        for name, value in self.server_state.default_headers:
+            content.extend([name, b": ", value, b"\r\n"])  # pragma: full coverage
+        content.extend(
+            [
+                b"content-type: text/plain; charset=utf-8\r\n",
+                b"content-length: " + str(len(msg)).encode("ascii") + b"\r\n",
+                b"connection: close\r\n",
+                b"\r\n",
+                msg.encode("ascii"),
+            ]
+        )
+        self.transport.write(b"".join(content))
+        self.transport.close()
+
+    def on_message_begin(self) -> None:
+        self.url = b""
+        self.expect_100_continue = False
+        self.headers = []
+        self.scope = {  # type: ignore[typeddict-item]
+            "type": "http",
+            "asgi": {"version": self.config.asgi_version, "spec_version": "2.3"},
+            "http_version": "1.1",
+            "server": self.server,
+            "client": self.client,
+            "scheme": self.scheme,  # type: ignore[typeddict-item]
+            "root_path": self.root_path,
+            "headers": self.headers,
+            "state": self.app_state.copy(),
+        }
+
+    # Parser callbacks
+    def on_url(self, url: bytes) -> None:
+        self.url += url
+
+    def on_header(self, name: bytes, value: bytes) -> None:
+        name = name.lower()
+        if name == b"expect" and value.lower() == b"100-continue":
+            self.expect_100_continue = True
+        self.headers.append((name, value))
+
+    def on_headers_complete(self) -> None:
+        http_version = self.parser.get_http_version()
+        method = self.parser.get_method()
+        self.scope["method"] = method.decode("ascii")
+        if http_version != "1.1":
+            self.scope["http_version"] = http_version
+        if self.parser.should_upgrade() and self._should_upgrade():
+            return
+        parsed_url = httptools.parse_url(self.url)
+        raw_path = parsed_url.path
+        path = raw_path.decode("ascii")
+        if "%" in path:
+            path = urllib.parse.unquote(path)
+        full_path = self.root_path + path
+        full_raw_path = self.root_path.encode("ascii") + raw_path
+        self.scope["path"] = full_path
+        self.scope["raw_path"] = full_raw_path
+        self.scope["query_string"] = parsed_url.query or b""
+
+        # Handle 503 responses when 'limit_concurrency' is exceeded.
+        if self.limit_concurrency is not None and (
+            len(self.connections) >= self.limit_concurrency or len(self.tasks) >= self.limit_concurrency
+        ):
+            app = service_unavailable
+            message = "Exceeded concurrency limit."
+            self.logger.warning(message)
+        else:
+            app = self.app
+
+        existing_cycle = self.cycle
+        self.cycle = RequestResponseCycle(
+            scope=self.scope,
+            transport=self.transport,
+            flow=self.flow,
+            logger=self.logger,
+            access_logger=self.access_logger,
+            access_log=self.access_log,
+            default_headers=self.server_state.default_headers,
+            message_event=asyncio.Event(),
+            expect_100_continue=self.expect_100_continue,
+            keep_alive=http_version != "1.0",
+            on_response=self.on_response_complete,
+        )
+        if existing_cycle is None or existing_cycle.response_complete:
+            # Standard case - start processing the request.
+            self._start_asgi_task(self.cycle, app)
+        else:
+            # Pipelined HTTP requests need to be queued up.
+            self.flow.pause_reading()
+            self.pipeline.appendleft((self.cycle, app))
+
+    def _start_asgi_task(self, cycle: RequestResponseCycle, app: ASGI3Application) -> None:
+        if self.config.reset_contextvars:
+            # Opt-in workaround for https://github.com/python/cpython/issues/140947:
+            # asyncio can leak context vars between tasks. Hides context set in the
+            # lifespan or by external instrumentation.
+            if sys.version_info >= (3, 11):  # pragma: py-lt-311
+                task = self.loop.create_task(cycle.run_asgi(app), context=contextvars.Context())
+            else:  # pragma: py-gte-311
+                task = contextvars.Context().run(self.loop.create_task, cycle.run_asgi(app))
+        else:
+            task = self.loop.create_task(cycle.run_asgi(app))
+        task.add_done_callback(self.tasks.discard)
+        self.tasks.add(task)
+
+    def on_body(self, body: bytes) -> None:
+        if (self.parser.should_upgrade() and self._should_upgrade()) or self.cycle.response_complete:
+            return
+        self.cycle.body += body
+        if len(self.cycle.body) > HIGH_WATER_LIMIT:
+            self.flow.pause_reading()
+        self.cycle.message_event.set()
+
+    def on_message_complete(self) -> None:
+        if (self.parser.should_upgrade() and self._should_upgrade()) or self.cycle.response_complete:
+            return
+        self.cycle.more_body = False
+        self.cycle.message_event.set()
+
+    def on_response_complete(self) -> None:
+        # Callback for pipelined HTTP requests to be started.
+        self.server_state.total_requests += 1
+
+        if self.transport.is_closing():
+            return
+
+        self._unset_keepalive_if_required()
+
+        # Unpause data reads if needed.
+        self.flow.resume_reading()
+
+        # Unblock any pipelined events. If there are none, arm the
+        # Keep-Alive timeout instead.
+        if self.pipeline:
+            cycle, app = self.pipeline.pop()
+            self._start_asgi_task(cycle, app)
+        else:
+            self.timeout_keep_alive_task = self.loop.call_later(
+                self.timeout_keep_alive, self.timeout_keep_alive_handler
+            )
+
+    def shutdown(self) -> None:
+        """
+        Called by the server to commence a graceful shutdown.
+        """
+        if self.cycle is None or self.cycle.response_complete:
+            self.transport.close()
+        else:
+            self.cycle.keep_alive = False
+
+    def pause_writing(self) -> None:
+        """
+        Called by the transport when the write buffer exceeds the high water mark.
+        """
+        self.flow.pause_writing()  # pragma: full coverage
+
+    def resume_writing(self) -> None:
+        """
+        Called by the transport when the write buffer drops below the low water mark.
+        """
+        self.flow.resume_writing()  # pragma: full coverage
+
+    def timeout_keep_alive_handler(self) -> None:
+        """
+        Called on a keep-alive connection if no new data is received after a short
+        delay.
+        """
+        if not self.transport.is_closing():
+            self.transport.close()
+
+
+class RequestResponseCycle:
+    def __init__(
+        self,
+        scope: HTTPScope,
+        transport: asyncio.Transport,
+        flow: FlowControl,
+        logger: logging.Logger,
+        access_logger: logging.Logger,
+        access_log: bool,
+        default_headers: list[tuple[bytes, bytes]],
+        message_event: asyncio.Event,
+        expect_100_continue: bool,
+        keep_alive: bool,
+        on_response: Callable[..., None],
+    ):
+        self.scope = scope
+        self.transport = transport
+        self.flow = flow
+        self.logger = logger
+        self.access_logger = access_logger
+        self.access_log = access_log
+        self.default_headers = default_headers
+        self.message_event = message_event
+        self.on_response = on_response
+
+        # Connection state
+        self.disconnected = False
+        self.keep_alive = keep_alive
+        self.waiting_for_100_continue = expect_100_continue
+
+        # Request state
+        self.body = bytearray()
+        self.more_body = True
+
+        # Response state
+        self.response_started = False
+        self.response_complete = False
+        self.chunked_encoding: bool | None = None
+        self.expected_content_length = 0
+
+    # ASGI exception wrapper
+    async def run_asgi(self, app: ASGI3Application) -> None:
+        try:
+            result = await app(  # type: ignore[func-returns-value]
+                self.scope, self.receive, self.send
+            )
+        except BaseException as exc:
+            msg = "Exception in ASGI application\n"
+            self.logger.error(msg, exc_info=exc)
+            if not self.response_started:
+                await self.send_500_response()
+            else:
+                self.transport.close()
+        else:
+            if result is not None:
+                msg = "ASGI callable should return None, but returned '%s'."
+                self.logger.error(msg, result)
+                self.transport.close()
+            elif not self.response_started and not self.disconnected:
+                msg = "ASGI callable returned without starting response."
+                self.logger.error(msg)
+                await self.send_500_response()
+            elif not self.response_complete and not self.disconnected:
+                msg = "ASGI callable returned without completing response."
+                self.logger.error(msg)
+                self.transport.close()
+        finally:
+            self.on_response = lambda: None
+
+    async def send_500_response(self) -> None:
+        await self.send(
+            {
+                "type": "http.response.start",
+                "status": 500,
+                "headers": [
+                    (b"content-type", b"text/plain; charset=utf-8"),
+                    (b"content-length", b"21"),
+                    (b"connection", b"close"),
+                ],
+            }
+        )
+        await self.send({"type": "http.response.body", "body": b"Internal Server Error", "more_body": False})
+
+    # ASGI interface
+    async def send(self, message: ASGISendEvent) -> None:
+        if self.flow.write_paused and not self.disconnected:
+            await self.flow.drain()  # pragma: full coverage
+
+        if self.disconnected:
+            return  # pragma: full coverage
+
+        if not self.response_started:
+            # Sending response status line and headers
+            if message["type"] != "http.response.start":
+                raise RuntimeError(f"Expected ASGI message 'http.response.start', but got '{message['type']}'.")
+
+            self.response_started = True
+            self.waiting_for_100_continue = False
+
+            status_code = message["status"]
+            headers = self.default_headers + list(message.get("headers", []))
+
+            if CLOSE_HEADER in self.scope["headers"] and CLOSE_HEADER not in headers:
+                headers = headers + [CLOSE_HEADER]
+
+            if self.access_log:
+                self.access_logger.info(
+                    '%s - "%s %s HTTP/%s" %d',
+                    get_client_addr(self.scope),
+                    self.scope["method"],
+                    get_path_with_query_string(self.scope),
+                    self.scope["http_version"],
+                    status_code,
+                )
+
+            # Write response status line and headers
+            content = [STATUS_LINE[status_code]]
+
+            for name, value in headers:
+                if HEADER_RE.search(name):
+                    raise RuntimeError("Invalid HTTP header name.")  # pragma: full coverage
+                if HEADER_VALUE_RE.search(value):
+                    raise RuntimeError("Invalid HTTP header value.")
+
+                name = name.lower()
+                if name == b"content-length" and self.chunked_encoding is None:
+                    self.expected_content_length = int(value.decode())
+                    self.chunked_encoding = False
+                elif name == b"transfer-encoding" and value.lower() == b"chunked":
+                    self.expected_content_length = 0
+                    self.chunked_encoding = True
+                elif name == b"connection" and value.lower() == b"close":
+                    self.keep_alive = False
+                content.extend([name, b": ", value, b"\r\n"])
+
+            if self.chunked_encoding is None and self.scope["method"] != "HEAD" and status_code not in (204, 304):
+                # Neither content-length nor transfer-encoding specified
+                self.chunked_encoding = True
+                content.append(b"transfer-encoding: chunked\r\n")
+
+            content.append(b"\r\n")
+            self.transport.write(b"".join(content))
+
+        elif not self.response_complete:
+            # Sending response body
+            if message["type"] != "http.response.body":
+                raise RuntimeError(f"Expected ASGI message 'http.response.body', but got '{message['type']}'.")
+
+            body = message.get("body", b"")
+            more_body = message.get("more_body", False)
+
+            # Write response body
+            if self.scope["method"] == "HEAD":
+                self.expected_content_length = 0
+            elif self.chunked_encoding:
+                if body:
+                    content = [b"%x\r\n" % len(body), body, b"\r\n"]
+                else:
+                    content = []
+                if not more_body:
+                    content.append(b"0\r\n\r\n")
+                self.transport.write(b"".join(content))
+            else:
+                num_bytes = len(body)
+                if num_bytes > self.expected_content_length:
+                    raise RuntimeError("Response content longer than Content-Length")
+                else:
+                    self.expected_content_length -= num_bytes
+                self.transport.write(body)
+
+            # Handle response completion
+            if not more_body:
+                if self.expected_content_length != 0:
+                    raise RuntimeError("Response content shorter than Content-Length")
+                self.response_complete = True
+                self.message_event.set()
+                if not self.keep_alive:
+                    self.transport.close()
+                self.on_response()
+
+        else:
+            # Response already sent
+            raise RuntimeError(f"Unexpected ASGI message '{message['type']}' sent, after response already completed.")
+
+    async def receive(self) -> ASGIReceiveEvent:
+        if self.waiting_for_100_continue and not self.transport.is_closing():
+            self.transport.write(b"HTTP/1.1 100 Continue\r\n\r\n")
+            self.waiting_for_100_continue = False
+
+        if not self.disconnected and not self.response_complete:
+            self.flow.resume_reading()
+            await self.message_event.wait()
+            self.message_event.clear()
+
+        if self.disconnected or self.response_complete:
+            return {"type": "http.disconnect"}
+        message: HTTPRequestEvent = {"type": "http.request", "body": bytes(self.body), "more_body": self.more_body}
+        self.body = bytearray()
+        return message