Edit File: web_ws.py
import asyncio import base64 import binascii import hashlib import json from typing import Any, Iterable, Optional, Tuple, cast import async_timeout import attr from multidict import CIMultiDict from . import hdrs from .abc import AbstractStreamWriter from .helpers import call_later, set_result from .http import ( WS_CLOSED_MESSAGE, WS_CLOSING_MESSAGE, WS_KEY, WebSocketError, WebSocketReader, WebSocketWriter, WSCloseCode, WSMessage, WSMsgType as WSMsgType, ws_ext_gen, ws_ext_parse, ) from .log import ws_logger from .streams import EofStream, FlowControlDataQueue from .typedefs import Final, JSONDecoder, JSONEncoder from .web_exceptions import HTTPBadRequest, HTTPException from .web_request import BaseRequest from .web_response import StreamResponse __all__ = ( "WebSocketResponse", "WebSocketReady", "WSMsgType", ) THRESHOLD_CONNLOST_ACCESS: Final[int] = 5 @attr.s(auto_attribs=True, frozen=True, slots=True) class WebSocketReady: ok: bool protocol: Optional[str] def __bool__(self) -> bool: return self.ok class WebSocketResponse(StreamResponse): _length_check = False def __init__( self, *, timeout: float = 10.0, receive_timeout: Optional[float] = None, autoclose: bool = True, autoping: bool = True, heartbeat: Optional[float] = None, protocols: Iterable[str] = (), compress: bool = True, max_msg_size: int = 4 * 1024 * 1024, ) -> None: super().__init__(status=101) self._protocols = protocols self._ws_protocol: Optional[str] = None self._writer: Optional[WebSocketWriter] = None self._reader: Optional[FlowControlDataQueue[WSMessage]] = None self._closed = False self._closing = False self._conn_lost = 0 self._close_code: Optional[int] = None self._loop: Optional[asyncio.AbstractEventLoop] = None self._waiting: Optional[asyncio.Future[bool]] = None self._exception: Optional[BaseException] = None self._timeout = timeout self._receive_timeout = receive_timeout self._autoclose = autoclose self._autoping = autoping self._heartbeat = heartbeat self._heartbeat_cb: Optional[asyncio.TimerHandle] = None if heartbeat is not None: self._pong_heartbeat = heartbeat / 2.0 self._pong_response_cb: Optional[asyncio.TimerHandle] = None self._compress = compress self._max_msg_size = max_msg_size def _cancel_heartbeat(self) -> None: if self._pong_response_cb is not None: self._pong_response_cb.cancel() self._pong_response_cb = None if self._heartbeat_cb is not None: self._heartbeat_cb.cancel() self._heartbeat_cb = None def _reset_heartbeat(self) -> None: self._cancel_heartbeat() if self._heartbeat is not None: assert self._loop is not None self._heartbeat_cb = call_later( self._send_heartbeat, self._heartbeat, self._loop ) def _send_heartbeat(self) -> None: if self._heartbeat is not None and not self._closed: assert self._loop is not None # fire-and-forget a task is not perfect but maybe ok for # sending ping. Otherwise we need a long-living heartbeat # task in the class. self._loop.create_task(self._writer.ping()) # type: ignore[union-attr] if self._pong_response_cb is not None: self._pong_response_cb.cancel() self._pong_response_cb = call_later( self._pong_not_received, self._pong_heartbeat, self._loop ) def _pong_not_received(self) -> None: if self._req is not None and self._req.transport is not None: self._closed = True self._close_code = WSCloseCode.ABNORMAL_CLOSURE self._exception = asyncio.TimeoutError() self._req.transport.close() async def prepare(self, request: BaseRequest) -> AbstractStreamWriter: # make pre-check to don't hide it by do_handshake() exceptions if self._payload_writer is not None: return self._payload_writer protocol, writer = self._pre_start(request) payload_writer = await super().prepare(request) assert payload_writer is not None self._post_start(request, protocol, writer) await payload_writer.drain() return payload_writer def _handshake( self, request: BaseRequest ) -> Tuple["CIMultiDict[str]", str, bool, bool]: headers = request.headers if "websocket" != headers.get(hdrs.UPGRADE, "").lower().strip(): raise HTTPBadRequest( text=( "No WebSocket UPGRADE hdr: {}\n Can " '"Upgrade" only to "WebSocket".' ).format(headers.get(hdrs.UPGRADE)) ) if "upgrade" not in headers.get(hdrs.CONNECTION, "").lower(): raise HTTPBadRequest( text="No CONNECTION upgrade hdr: {}".format( headers.get(hdrs.CONNECTION) ) ) # find common sub-protocol between client and server protocol = None if hdrs.SEC_WEBSOCKET_PROTOCOL in headers: req_protocols = [ str(proto.strip()) for proto in headers[hdrs.SEC_WEBSOCKET_PROTOCOL].split(",") ] for proto in req_protocols: if proto in self._protocols: protocol = proto break else: # No overlap found: Return no protocol as per spec ws_logger.warning( "Client protocols %r don’t overlap server-known ones %r", req_protocols, self._protocols, ) # check supported version version = headers.get(hdrs.SEC_WEBSOCKET_VERSION, "") if version not in ("13", "8", "7"): raise HTTPBadRequest(text=f"Unsupported version: {version}") # check client handshake for validity key = headers.get(hdrs.SEC_WEBSOCKET_KEY) try: if not key or len(base64.b64decode(key)) != 16: raise HTTPBadRequest(text=f"Handshake error: {key!r}") except binascii.Error: raise HTTPBadRequest(text=f"Handshake error: {key!r}") from None accept_val = base64.b64encode( hashlib.sha1(key.encode() + WS_KEY).digest() ).decode() response_headers = CIMultiDict( { hdrs.UPGRADE: "websocket", hdrs.CONNECTION: "upgrade", hdrs.SEC_WEBSOCKET_ACCEPT: accept_val, } ) notakeover = False compress = 0 if self._compress: extensions = headers.get(hdrs.SEC_WEBSOCKET_EXTENSIONS) # Server side always get return with no exception. # If something happened, just drop compress extension compress, notakeover = ws_ext_parse(extensions, isserver=True) if compress: enabledext = ws_ext_gen( compress=compress, isserver=True, server_notakeover=notakeover ) response_headers[hdrs.SEC_WEBSOCKET_EXTENSIONS] = enabledext if protocol: response_headers[hdrs.SEC_WEBSOCKET_PROTOCOL] = protocol return ( response_headers, protocol, compress, notakeover, ) # type: ignore[return-value] def _pre_start(self, request: BaseRequest) -> Tuple[str, WebSocketWriter]: self._loop = request._loop headers, protocol, compress, notakeover = self._handshake(request) self.set_status(101) self.headers.update(headers) self.force_close() self._compress = compress transport = request._protocol.transport assert transport is not None writer = WebSocketWriter( request._protocol, transport, compress=compress, notakeover=notakeover ) return protocol, writer def _post_start( self, request: BaseRequest, protocol: str, writer: WebSocketWriter ) -> None: self._ws_protocol = protocol self._writer = writer self._reset_heartbeat() loop = self._loop assert loop is not None self._reader = FlowControlDataQueue(request._protocol, 2**16, loop=loop) request.protocol.set_parser( WebSocketReader(self._reader, self._max_msg_size, compress=self._compress) ) # disable HTTP keepalive for WebSocket request.protocol.keep_alive(False) def can_prepare(self, request: BaseRequest) -> WebSocketReady: if self._writer is not None: raise RuntimeError("Already started") try: _, protocol, _, _ = self._handshake(request) except HTTPException: return WebSocketReady(False, None) else: return WebSocketReady(True, protocol) @property def closed(self) -> bool: return self._closed @property def close_code(self) -> Optional[int]: return self._close_code @property def ws_protocol(self) -> Optional[str]: return self._ws_protocol @property def compress(self) -> bool: return self._compress def exception(self) -> Optional[BaseException]: return self._exception async def ping(self, message: bytes = b"") -> None: if self._writer is None: raise RuntimeError("Call .prepare() first") await self._writer.ping(message) async def pong(self, message: bytes = b"") -> None: # unsolicited pong if self._writer is None: raise RuntimeError("Call .prepare() first") await self._writer.pong(message) async def send_str(self, data: str, compress: Optional[bool] = None) -> None: if self._writer is None: raise RuntimeError("Call .prepare() first") if not isinstance(data, str): raise TypeError("data argument must be str (%r)" % type(data)) await self._writer.send(data, binary=False, compress=compress) async def send_bytes(self, data: bytes, compress: Optional[bool] = None) -> None: if self._writer is None: raise RuntimeError("Call .prepare() first") if not isinstance(data, (bytes, bytearray, memoryview)): raise TypeError("data argument must be byte-ish (%r)" % type(data)) await self._writer.send(data, binary=True, compress=compress) async def send_json( self, data: Any, compress: Optional[bool] = None, *, dumps: JSONEncoder = json.dumps, ) -> None: await self.send_str(dumps(data), compress=compress) async def write_eof(self) -> None: # type: ignore[override] if self._eof_sent: return if self._payload_writer is None: raise RuntimeError("Response has not been started") await self.close() self._eof_sent = True async def close(self, *, code: int = WSCloseCode.OK, message: bytes = b"") -> bool: if self._writer is None: raise RuntimeError("Call .prepare() first") self._cancel_heartbeat() reader = self._reader assert reader is not None # we need to break `receive()` cycle first, # `close()` may be called from different task if self._waiting is not None and not self._closed: reader.feed_data(WS_CLOSING_MESSAGE, 0) await self._waiting if not self._closed: self._closed = True try: await self._writer.close(code, message) writer = self._payload_writer assert writer is not None await writer.drain() except (asyncio.CancelledError, asyncio.TimeoutError): self._close_code = WSCloseCode.ABNORMAL_CLOSURE raise except Exception as exc: self._close_code = WSCloseCode.ABNORMAL_CLOSURE self._exception = exc return True if self._closing: return True reader = self._reader assert reader is not None try: async with async_timeout.timeout(self._timeout): msg = await reader.read() except asyncio.CancelledError: self._close_code = WSCloseCode.ABNORMAL_CLOSURE raise except Exception as exc: self._close_code = WSCloseCode.ABNORMAL_CLOSURE self._exception = exc return True if msg.type == WSMsgType.CLOSE: self._close_code = msg.data return True self._close_code = WSCloseCode.ABNORMAL_CLOSURE self._exception = asyncio.TimeoutError() return True else: return False async def receive(self, timeout: Optional[float] = None) -> WSMessage: if self._reader is None: raise RuntimeError("Call .prepare() first") loop = self._loop assert loop is not None while True: if self._waiting is not None: raise RuntimeError("Concurrent call to receive() is not allowed") if self._closed: self._conn_lost += 1 if self._conn_lost >= THRESHOLD_CONNLOST_ACCESS: raise RuntimeError("WebSocket connection is closed.") return WS_CLOSED_MESSAGE elif self._closing: return WS_CLOSING_MESSAGE try: self._waiting = loop.create_future() try: async with async_timeout.timeout(timeout or self._receive_timeout): msg = await self._reader.read() self._reset_heartbeat() finally: waiter = self._waiting set_result(waiter, True) self._waiting = None except (asyncio.CancelledError, asyncio.TimeoutError): self._close_code = WSCloseCode.ABNORMAL_CLOSURE raise except EofStream: self._close_code = WSCloseCode.OK await self.close() return WSMessage(WSMsgType.CLOSED, None, None) except WebSocketError as exc: self._close_code = exc.code await self.close(code=exc.code) return WSMessage(WSMsgType.ERROR, exc, None) except Exception as exc: self._exception = exc self._closing = True self._close_code = WSCloseCode.ABNORMAL_CLOSURE await self.close() return WSMessage(WSMsgType.ERROR, exc, None) if msg.type == WSMsgType.CLOSE: self._closing = True self._close_code = msg.data if not self._closed and self._autoclose: await self.close() elif msg.type == WSMsgType.CLOSING: self._closing = True elif msg.type == WSMsgType.PING and self._autoping: await self.pong(msg.data) continue elif msg.type == WSMsgType.PONG and self._autoping: continue return msg async def receive_str(self, *, timeout: Optional[float] = None) -> str: msg = await self.receive(timeout) if msg.type != WSMsgType.TEXT: raise TypeError( "Received message {}:{!r} is not WSMsgType.TEXT".format( msg.type, msg.data ) ) return cast(str, msg.data) async def receive_bytes(self, *, timeout: Optional[float] = None) -> bytes: msg = await self.receive(timeout) if msg.type != WSMsgType.BINARY: raise TypeError(f"Received message {msg.type}:{msg.data!r} is not bytes") return cast(bytes, msg.data) async def receive_json( self, *, loads: JSONDecoder = json.loads, timeout: Optional[float] = None ) -> Any: data = await self.receive_str(timeout=timeout) return loads(data) async def write(self, data: bytes) -> None: raise RuntimeError("Cannot call .write() for websocket") def __aiter__(self) -> "WebSocketResponse": return self async def __anext__(self) -> WSMessage: msg = await self.receive() if msg.type in (WSMsgType.CLOSE, WSMsgType.CLOSING, WSMsgType.CLOSED): raise StopAsyncIteration return msg def _cancel(self, exc: BaseException) -> None: if self._reader is not None: self._reader.set_exception(exc)