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Editing: web_protocol.py
import asyncio import asyncio.streams import traceback import warnings from collections import deque from contextlib import suppress from html import escape as html_escape from http import HTTPStatus from logging import Logger from typing import ( TYPE_CHECKING, Any, Awaitable, Callable, Deque, Optional, Sequence, Tuple, Type, Union, cast, ) import attr import yarl from .abc import AbstractAccessLogger, AbstractStreamWriter from .base_protocol import BaseProtocol from .helpers import ceil_timeout from .http import ( HttpProcessingError, HttpRequestParser, HttpVersion10, RawRequestMessage, StreamWriter, ) from .log import access_logger, server_logger from .streams import EMPTY_PAYLOAD, StreamReader from .tcp_helpers import tcp_keepalive from .web_exceptions import HTTPException from .web_log import AccessLogger from .web_request import BaseRequest from .web_response import Response, StreamResponse __all__ = ("RequestHandler", "RequestPayloadError", "PayloadAccessError") if TYPE_CHECKING: from .web_server import Server _RequestFactory = Callable[ [ RawRequestMessage, StreamReader, "RequestHandler", AbstractStreamWriter, "asyncio.Task[None]", ], BaseRequest, ] _RequestHandler = Callable[[BaseRequest], Awaitable[StreamResponse]] ERROR = RawRequestMessage( "UNKNOWN", "/", HttpVersion10, {}, # type: ignore[arg-type] {}, # type: ignore[arg-type] True, None, False, False, yarl.URL("/"), ) class RequestPayloadError(Exception): """Payload parsing error.""" class PayloadAccessError(Exception): """Payload was accessed after response was sent.""" @attr.s(auto_attribs=True, frozen=True, slots=True) class _ErrInfo: status: int exc: BaseException message: str _MsgType = Tuple[Union[RawRequestMessage, _ErrInfo], StreamReader] class RequestHandler(BaseProtocol): """HTTP protocol implementation. RequestHandler handles incoming HTTP request. It reads request line, request headers and request payload and calls handle_request() method. By default it always returns with 404 response. RequestHandler handles errors in incoming request, like bad status line, bad headers or incomplete payload. If any error occurs, connection gets closed. keepalive_timeout -- number of seconds before closing keep-alive connection tcp_keepalive -- TCP keep-alive is on, default is on debug -- enable debug mode logger -- custom logger object access_log_class -- custom class for access_logger access_log -- custom logging object access_log_format -- access log format string loop -- Optional event loop max_line_size -- Optional maximum header line size max_field_size -- Optional maximum header field size max_headers -- Optional maximum header size timeout_ceil_threshold -- Optional value to specify threshold to ceil() timeout values """ KEEPALIVE_RESCHEDULE_DELAY = 1 __slots__ = ( "_request_count", "_keepalive", "_manager", "_request_handler", "_request_factory", "_tcp_keepalive", "_keepalive_time", "_keepalive_handle", "_keepalive_timeout", "_lingering_time", "_messages", "_message_tail", "_waiter", "_task_handler", "_upgrade", "_payload_parser", "_request_parser", "_reading_paused", "logger", "debug", "access_log", "access_logger", "_close", "_force_close", "_current_request", "_timeout_ceil_threshold", ) def __init__( self, manager: "Server", *, loop: asyncio.AbstractEventLoop, keepalive_timeout: float = 75.0, # NGINX default is 75 secs tcp_keepalive: bool = True, logger: Logger = server_logger, access_log_class: Type[AbstractAccessLogger] = AccessLogger, access_log: Logger = access_logger, access_log_format: str = AccessLogger.LOG_FORMAT, debug: bool = False, max_line_size: int = 8190, max_headers: int = 32768, max_field_size: int = 8190, lingering_time: float = 10.0, read_bufsize: int = 2**16, auto_decompress: bool = True, timeout_ceil_threshold: float = 5, ): super().__init__(loop) self._request_count = 0 self._keepalive = False self._current_request: Optional[BaseRequest] = None self._manager: Optional[Server] = manager self._request_handler: Optional[_RequestHandler] = manager.request_handler self._request_factory: Optional[_RequestFactory] = manager.request_factory self._tcp_keepalive = tcp_keepalive # placeholder to be replaced on keepalive timeout setup self._keepalive_time = 0.0 self._keepalive_handle: Optional[asyncio.Handle] = None self._keepalive_timeout = keepalive_timeout self._lingering_time = float(lingering_time) self._messages: Deque[_MsgType] = deque() self._message_tail = b"" self._waiter: Optional[asyncio.Future[None]] = None self._task_handler: Optional[asyncio.Task[None]] = None self._upgrade = False self._payload_parser: Any = None self._request_parser: Optional[HttpRequestParser] = HttpRequestParser( self, loop, read_bufsize, max_line_size=max_line_size, max_field_size=max_field_size, max_headers=max_headers, payload_exception=RequestPayloadError, auto_decompress=auto_decompress, ) self._timeout_ceil_threshold: float = 5 try: self._timeout_ceil_threshold = float(timeout_ceil_threshold) except (TypeError, ValueError): pass self.logger = logger self.debug = debug self.access_log = access_log if access_log: self.access_logger: Optional[AbstractAccessLogger] = access_log_class( access_log, access_log_format ) else: self.access_logger = None self._close = False self._force_close = False def __repr__(self) -> str: return "<{} {}>".format( self.__class__.__name__, "connected" if self.transport is not None else "disconnected", ) @property def keepalive_timeout(self) -> float: return self._keepalive_timeout async def shutdown(self, timeout: Optional[float] = 15.0) -> None: """Do worker process exit preparations. We need to clean up everything and stop accepting requests. It is especially important for keep-alive connections. """ self._force_close = True if self._keepalive_handle is not None: self._keepalive_handle.cancel() if self._waiter: self._waiter.cancel() # wait for handlers with suppress(asyncio.CancelledError, asyncio.TimeoutError): async with ceil_timeout(timeout): if self._current_request is not None: self._current_request._cancel(asyncio.CancelledError()) if self._task_handler is not None and not self._task_handler.done(): await self._task_handler # force-close non-idle handler if self._task_handler is not None: self._task_handler.cancel() if self.transport is not None: self.transport.close() self.transport = None def connection_made(self, transport: asyncio.BaseTransport) -> None: super().connection_made(transport) real_transport = cast(asyncio.Transport, transport) if self._tcp_keepalive: tcp_keepalive(real_transport) self._task_handler = self._loop.create_task(self.start()) assert self._manager is not None self._manager.connection_made(self, real_transport) def connection_lost(self, exc: Optional[BaseException]) -> None: if self._manager is None: return self._manager.connection_lost(self, exc) super().connection_lost(exc) # Grab value before setting _manager to None. handler_cancellation = self._manager.handler_cancellation self._manager = None self._force_close = True self._request_factory = None self._request_handler = None self._request_parser = None if self._keepalive_handle is not None: self._keepalive_handle.cancel() if self._current_request is not None: if exc is None: exc = ConnectionResetError("Connection lost") self._current_request._cancel(exc) if self._waiter is not None: self._waiter.cancel() if handler_cancellation and self._task_handler is not None: self._task_handler.cancel() self._task_handler = None if self._payload_parser is not None: self._payload_parser.feed_eof() self._payload_parser = None def set_parser(self, parser: Any) -> None: # Actual type is WebReader assert self._payload_parser is None self._payload_parser = parser if self._message_tail: self._payload_parser.feed_data(self._message_tail) self._message_tail = b"" def eof_received(self) -> None: pass def data_received(self, data: bytes) -> None: if self._force_close or self._close: return # parse http messages messages: Sequence[_MsgType] if self._payload_parser is None and not self._upgrade: assert self._request_parser is not None try: messages, upgraded, tail = self._request_parser.feed_data(data) except HttpProcessingError as exc: messages = [ (_ErrInfo(status=400, exc=exc, message=exc.message), EMPTY_PAYLOAD) ] upgraded = False tail = b"" for msg, payload in messages or (): self._request_count += 1 self._messages.append((msg, payload)) waiter = self._waiter if messages and waiter is not None and not waiter.done(): # don't set result twice waiter.set_result(None) self._upgrade = upgraded if upgraded and tail: self._message_tail = tail # no parser, just store elif self._payload_parser is None and self._upgrade and data: self._message_tail += data # feed payload elif data: eof, tail = self._payload_parser.feed_data(data) if eof: self.close() def keep_alive(self, val: bool) -> None: """Set keep-alive connection mode. :param bool val: new state. """ self._keepalive = val if self._keepalive_handle: self._keepalive_handle.cancel() self._keepalive_handle = None def close(self) -> None: """Close connection. Stop accepting new pipelining messages and close connection when handlers done processing messages. """ self._close = True if self._waiter: self._waiter.cancel() def force_close(self) -> None: """Forcefully close connection.""" self._force_close = True if self._waiter: self._waiter.cancel() if self.transport is not None: self.transport.close() self.transport = None def log_access( self, request: BaseRequest, response: StreamResponse, time: float ) -> None: if self.access_logger is not None: self.access_logger.log(request, response, self._loop.time() - time) def log_debug(self, *args: Any, **kw: Any) -> None: if self.debug: self.logger.debug(*args, **kw) def log_exception(self, *args: Any, **kw: Any) -> None: self.logger.exception(*args, **kw) def _process_keepalive(self) -> None: if self._force_close or not self._keepalive: return next = self._keepalive_time + self._keepalive_timeout # handler in idle state if self._waiter: if self._loop.time() > next: self.force_close() return # not all request handlers are done, # reschedule itself to next second self._keepalive_handle = self._loop.call_later( self.KEEPALIVE_RESCHEDULE_DELAY, self._process_keepalive, ) async def _handle_request( self, request: BaseRequest, start_time: float, request_handler: Callable[[BaseRequest], Awaitable[StreamResponse]], ) -> Tuple[StreamResponse, bool]: assert self._request_handler is not None try: try: self._current_request = request resp = await request_handler(request) finally: self._current_request = None except HTTPException as exc: resp = exc reset = await self.finish_response(request, resp, start_time) except asyncio.CancelledError: raise except asyncio.TimeoutError as exc: self.log_debug("Request handler timed out.", exc_info=exc) resp = self.handle_error(request, 504) reset = await self.finish_response(request, resp, start_time) except Exception as exc: resp = self.handle_error(request, 500, exc) reset = await self.finish_response(request, resp, start_time) else: # Deprecation warning (See #2415) if getattr(resp, "__http_exception__", False): warnings.warn( "returning HTTPException object is deprecated " "(#2415) and will be removed, " "please raise the exception instead", DeprecationWarning, ) reset = await self.finish_response(request, resp, start_time) return resp, reset async def start(self) -> None: """Process incoming request. It reads request line, request headers and request payload, then calls handle_request() method. Subclass has to override handle_request(). start() handles various exceptions in request or response handling. Connection is being closed always unless keep_alive(True) specified. """ loop = self._loop handler = self._task_handler assert handler is not None manager = self._manager assert manager is not None keepalive_timeout = self._keepalive_timeout resp = None assert self._request_factory is not None assert self._request_handler is not None while not self._force_close: if not self._messages: try: # wait for next request self._waiter = loop.create_future() await self._waiter except asyncio.CancelledError: break finally: self._waiter = None message, payload = self._messages.popleft() start = loop.time() manager.requests_count += 1 writer = StreamWriter(self, loop) if isinstance(message, _ErrInfo): # make request_factory work request_handler = self._make_error_handler(message) message = ERROR else: request_handler = self._request_handler request = self._request_factory(message, payload, self, writer, handler) try: # a new task is used for copy context vars (#3406) task = self._loop.create_task( self._handle_request(request, start, request_handler) ) try: resp, reset = await task except (asyncio.CancelledError, ConnectionError): self.log_debug("Ignored premature client disconnection") break # Drop the processed task from asyncio.Task.all_tasks() early del task if reset: self.log_debug("Ignored premature client disconnection 2") break # notify server about keep-alive self._keepalive = bool(resp.keep_alive) # check payload if not payload.is_eof(): lingering_time = self._lingering_time if not self._force_close and lingering_time: self.log_debug( "Start lingering close timer for %s sec.", lingering_time ) now = loop.time() end_t = now + lingering_time with suppress(asyncio.TimeoutError, asyncio.CancelledError): while not payload.is_eof() and now < end_t: async with ceil_timeout(end_t - now): # read and ignore await payload.readany() now = loop.time() # if payload still uncompleted if not payload.is_eof() and not self._force_close: self.log_debug("Uncompleted request.") self.close() payload.set_exception(PayloadAccessError()) except asyncio.CancelledError: self.log_debug("Ignored premature client disconnection ") break except RuntimeError as exc: if self.debug: self.log_exception("Unhandled runtime exception", exc_info=exc) self.force_close() except Exception as exc: self.log_exception("Unhandled exception", exc_info=exc) self.force_close() finally: if self.transport is None and resp is not None: self.log_debug("Ignored premature client disconnection.") elif not self._force_close: if self._keepalive and not self._close: # start keep-alive timer if keepalive_timeout is not None: now = self._loop.time() self._keepalive_time = now if self._keepalive_handle is None: self._keepalive_handle = loop.call_at( now + keepalive_timeout, self._process_keepalive ) else: break # remove handler, close transport if no handlers left if not self._force_close: self._task_handler = None if self.transport is not None: self.transport.close() async def finish_response( self, request: BaseRequest, resp: StreamResponse, start_time: float ) -> bool: """Prepare the response and write_eof, then log access. This has to be called within the context of any exception so the access logger can get exception information. Returns True if the client disconnects prematurely. """ if self._request_parser is not None: self._request_parser.set_upgraded(False) self._upgrade = False if self._message_tail: self._request_parser.feed_data(self._message_tail) self._message_tail = b"" try: prepare_meth = resp.prepare except AttributeError: if resp is None: raise RuntimeError("Missing return " "statement on request handler") else: raise RuntimeError( "Web-handler should return " "a response instance, " "got {!r}".format(resp) ) try: await prepare_meth(request) await resp.write_eof() except ConnectionError: self.log_access(request, resp, start_time) return True else: self.log_access(request, resp, start_time) return False def handle_error( self, request: BaseRequest, status: int = 500, exc: Optional[BaseException] = None, message: Optional[str] = None, ) -> StreamResponse: """Handle errors. Returns HTTP response with specific status code. Logs additional information. It always closes current connection. """ self.log_exception("Error handling request", exc_info=exc) # some data already got sent, connection is broken if request.writer.output_size > 0: raise ConnectionError( "Response is sent already, cannot send another response " "with the error message" ) ct = "text/plain" if status == HTTPStatus.INTERNAL_SERVER_ERROR: title = "{0.value} {0.phrase}".format(HTTPStatus.INTERNAL_SERVER_ERROR) msg = HTTPStatus.INTERNAL_SERVER_ERROR.description tb = None if self.debug: with suppress(Exception): tb = traceback.format_exc() if "text/html" in request.headers.get("Accept", ""): if tb: tb = html_escape(tb) msg = f"<h2>Traceback:</h2>\n<pre>{tb}</pre>" message = ( "<html><head>" "<title>{title}</title>" "</head><body>\n<h1>{title}</h1>" "\n{msg}\n</body></html>\n" ).format(title=title, msg=msg) ct = "text/html" else: if tb: msg = tb message = title + "\n\n" + msg resp = Response(status=status, text=message, content_type=ct) resp.force_close() return resp def _make_error_handler( self, err_info: _ErrInfo ) -> Callable[[BaseRequest], Awaitable[StreamResponse]]: async def handler(request: BaseRequest) -> StreamResponse: return self.handle_error( request, err_info.status, err_info.exc, err_info.message ) return handler
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