458 lines
17 KiB
Python
458 lines
17 KiB
Python
import asyncio
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import base64
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import binascii
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import hashlib
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import json
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from typing import Any, Iterable, Optional, Tuple
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import async_timeout
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import attr
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from multidict import CIMultiDict
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from . import hdrs
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from .abc import AbstractStreamWriter
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from .helpers import call_later, set_result
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from .http import (
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WS_CLOSED_MESSAGE,
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WS_CLOSING_MESSAGE,
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WS_KEY,
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WebSocketError,
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WebSocketReader,
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WebSocketWriter,
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WSMessage,
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)
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from .http import WSMsgType as WSMsgType
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from .http import ws_ext_gen, ws_ext_parse
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from .log import ws_logger
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from .streams import EofStream, FlowControlDataQueue
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from .typedefs import JSONDecoder, JSONEncoder
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from .web_exceptions import HTTPBadRequest, HTTPException
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from .web_request import BaseRequest
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from .web_response import StreamResponse
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__all__ = ('WebSocketResponse', 'WebSocketReady', 'WSMsgType',)
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THRESHOLD_CONNLOST_ACCESS = 5
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@attr.s(frozen=True, slots=True)
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class WebSocketReady:
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ok = attr.ib(type=bool)
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protocol = attr.ib(type=Optional[str])
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def __bool__(self) -> bool:
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return self.ok
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class WebSocketResponse(StreamResponse):
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_length_check = False
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def __init__(self, *,
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timeout: float=10.0, receive_timeout: Optional[float]=None,
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autoclose: bool=True, autoping: bool=True,
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heartbeat: Optional[float]=None,
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protocols: Iterable[str]=(),
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compress: bool=True, max_msg_size: int=4*1024*1024) -> None:
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super().__init__(status=101)
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self._protocols = protocols
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self._ws_protocol = None # type: Optional[str]
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self._writer = None # type: Optional[WebSocketWriter]
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self._reader = None # type: Optional[FlowControlDataQueue[WSMessage]]
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self._closed = False
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self._closing = False
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self._conn_lost = 0
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self._close_code = None # type: Optional[int]
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self._loop = None # type: Optional[asyncio.AbstractEventLoop]
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self._waiting = None # type: Optional[asyncio.Future[bool]]
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self._exception = None # type: Optional[BaseException]
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self._timeout = timeout
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self._receive_timeout = receive_timeout
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self._autoclose = autoclose
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self._autoping = autoping
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self._heartbeat = heartbeat
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self._heartbeat_cb = None
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if heartbeat is not None:
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self._pong_heartbeat = heartbeat / 2.0
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self._pong_response_cb = None
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self._compress = compress
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self._max_msg_size = max_msg_size
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def _cancel_heartbeat(self) -> None:
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if self._pong_response_cb is not None:
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self._pong_response_cb.cancel()
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self._pong_response_cb = None
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if self._heartbeat_cb is not None:
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self._heartbeat_cb.cancel()
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self._heartbeat_cb = None
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def _reset_heartbeat(self) -> None:
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self._cancel_heartbeat()
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if self._heartbeat is not None:
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self._heartbeat_cb = call_later(
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self._send_heartbeat, self._heartbeat, self._loop)
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def _send_heartbeat(self) -> None:
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if self._heartbeat is not None and not self._closed:
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# fire-and-forget a task is not perfect but maybe ok for
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# sending ping. Otherwise we need a long-living heartbeat
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# task in the class.
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self._loop.create_task(self._writer.ping()) # type: ignore
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if self._pong_response_cb is not None:
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self._pong_response_cb.cancel()
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self._pong_response_cb = call_later(
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self._pong_not_received, self._pong_heartbeat, self._loop)
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def _pong_not_received(self) -> None:
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if self._req is not None and self._req.transport is not None:
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self._closed = True
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self._close_code = 1006
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self._exception = asyncio.TimeoutError()
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self._req.transport.close()
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async def prepare(self, request: BaseRequest) -> AbstractStreamWriter:
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# make pre-check to don't hide it by do_handshake() exceptions
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if self._payload_writer is not None:
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return self._payload_writer
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protocol, writer = self._pre_start(request)
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payload_writer = await super().prepare(request)
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assert payload_writer is not None
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self._post_start(request, protocol, writer)
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await payload_writer.drain()
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return payload_writer
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def _handshake(self, request: BaseRequest) -> Tuple['CIMultiDict[str]',
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str,
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bool,
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bool]:
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headers = request.headers
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if 'websocket' != headers.get(hdrs.UPGRADE, '').lower().strip():
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raise HTTPBadRequest(
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text=('No WebSocket UPGRADE hdr: {}\n Can '
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'"Upgrade" only to "WebSocket".')
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.format(headers.get(hdrs.UPGRADE)))
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if 'upgrade' not in headers.get(hdrs.CONNECTION, '').lower():
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raise HTTPBadRequest(
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text='No CONNECTION upgrade hdr: {}'.format(
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headers.get(hdrs.CONNECTION)))
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# find common sub-protocol between client and server
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protocol = None
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if hdrs.SEC_WEBSOCKET_PROTOCOL in headers:
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req_protocols = [str(proto.strip()) for proto in
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headers[hdrs.SEC_WEBSOCKET_PROTOCOL].split(',')]
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for proto in req_protocols:
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if proto in self._protocols:
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protocol = proto
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break
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else:
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# No overlap found: Return no protocol as per spec
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ws_logger.warning(
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'Client protocols %r don’t overlap server-known ones %r',
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req_protocols, self._protocols)
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# check supported version
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version = headers.get(hdrs.SEC_WEBSOCKET_VERSION, '')
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if version not in ('13', '8', '7'):
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raise HTTPBadRequest(
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text='Unsupported version: {}'.format(version))
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# check client handshake for validity
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key = headers.get(hdrs.SEC_WEBSOCKET_KEY)
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try:
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if not key or len(base64.b64decode(key)) != 16:
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raise HTTPBadRequest(
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text='Handshake error: {!r}'.format(key))
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except binascii.Error:
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raise HTTPBadRequest(
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text='Handshake error: {!r}'.format(key)) from None
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accept_val = base64.b64encode(
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hashlib.sha1(key.encode() + WS_KEY).digest()).decode()
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response_headers = CIMultiDict( # type: ignore
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{hdrs.UPGRADE: 'websocket', # type: ignore
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hdrs.CONNECTION: 'upgrade',
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hdrs.SEC_WEBSOCKET_ACCEPT: accept_val})
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notakeover = False
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compress = 0
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if self._compress:
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extensions = headers.get(hdrs.SEC_WEBSOCKET_EXTENSIONS)
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# Server side always get return with no exception.
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# If something happened, just drop compress extension
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compress, notakeover = ws_ext_parse(extensions, isserver=True)
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if compress:
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enabledext = ws_ext_gen(compress=compress, isserver=True,
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server_notakeover=notakeover)
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response_headers[hdrs.SEC_WEBSOCKET_EXTENSIONS] = enabledext
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if protocol:
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response_headers[hdrs.SEC_WEBSOCKET_PROTOCOL] = protocol
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return (response_headers, # type: ignore
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protocol,
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compress,
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notakeover)
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def _pre_start(self, request: BaseRequest) -> Tuple[str, WebSocketWriter]:
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self._loop = request._loop
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headers, protocol, compress, notakeover = self._handshake(
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request)
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self.set_status(101)
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self.headers.update(headers)
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self.force_close()
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self._compress = compress
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transport = request._protocol.transport
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assert transport is not None
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writer = WebSocketWriter(request._protocol,
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transport,
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compress=compress,
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notakeover=notakeover)
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return protocol, writer
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def _post_start(self, request: BaseRequest,
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protocol: str, writer: WebSocketWriter) -> None:
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self._ws_protocol = protocol
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self._writer = writer
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self._reset_heartbeat()
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loop = self._loop
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assert loop is not None
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self._reader = FlowControlDataQueue(
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request._protocol, limit=2 ** 16, loop=loop)
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request.protocol.set_parser(WebSocketReader(
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self._reader, self._max_msg_size, compress=self._compress))
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# disable HTTP keepalive for WebSocket
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request.protocol.keep_alive(False)
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def can_prepare(self, request: BaseRequest) -> WebSocketReady:
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if self._writer is not None:
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raise RuntimeError('Already started')
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try:
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_, protocol, _, _ = self._handshake(request)
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except HTTPException:
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return WebSocketReady(False, None)
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else:
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return WebSocketReady(True, protocol)
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@property
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def closed(self) -> bool:
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return self._closed
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@property
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def close_code(self) -> Optional[int]:
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return self._close_code
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@property
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def ws_protocol(self) -> Optional[str]:
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return self._ws_protocol
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@property
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def compress(self) -> bool:
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return self._compress
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def exception(self) -> Optional[BaseException]:
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return self._exception
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async def ping(self, message: bytes=b'') -> None:
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if self._writer is None:
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raise RuntimeError('Call .prepare() first')
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await self._writer.ping(message)
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async def pong(self, message: bytes=b'') -> None:
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# unsolicited pong
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if self._writer is None:
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raise RuntimeError('Call .prepare() first')
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await self._writer.pong(message)
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async def send_str(self, data: str, compress: Optional[bool]=None) -> None:
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if self._writer is None:
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raise RuntimeError('Call .prepare() first')
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if not isinstance(data, str):
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raise TypeError('data argument must be str (%r)' % type(data))
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await self._writer.send(data, binary=False, compress=compress)
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async def send_bytes(self, data: bytes,
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compress: Optional[bool]=None) -> None:
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if self._writer is None:
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raise RuntimeError('Call .prepare() first')
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if not isinstance(data, (bytes, bytearray, memoryview)):
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raise TypeError('data argument must be byte-ish (%r)' %
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type(data))
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await self._writer.send(data, binary=True, compress=compress)
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async def send_json(self, data: Any, compress: Optional[bool]=None, *,
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dumps: JSONEncoder=json.dumps) -> None:
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await self.send_str(dumps(data), compress=compress)
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async def write_eof(self) -> None: # type: ignore
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if self._eof_sent:
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return
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if self._payload_writer is None:
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raise RuntimeError("Response has not been started")
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await self.close()
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self._eof_sent = True
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async def close(self, *, code: int=1000, message: bytes=b'') -> bool:
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if self._writer is None:
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raise RuntimeError('Call .prepare() first')
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self._cancel_heartbeat()
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reader = self._reader
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assert reader is not None
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# we need to break `receive()` cycle first,
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# `close()` may be called from different task
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if self._waiting is not None and not self._closed:
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reader.feed_data(WS_CLOSING_MESSAGE, 0)
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await self._waiting
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if not self._closed:
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self._closed = True
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try:
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await self._writer.close(code, message)
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writer = self._payload_writer
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assert writer is not None
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await writer.drain()
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except (asyncio.CancelledError, asyncio.TimeoutError):
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self._close_code = 1006
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raise
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except Exception as exc:
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self._close_code = 1006
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self._exception = exc
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return True
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if self._closing:
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return True
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reader = self._reader
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assert reader is not None
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try:
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with async_timeout.timeout(self._timeout, loop=self._loop):
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msg = await reader.read()
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except asyncio.CancelledError:
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self._close_code = 1006
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raise
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except Exception as exc:
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self._close_code = 1006
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self._exception = exc
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return True
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if msg.type == WSMsgType.CLOSE:
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self._close_code = msg.data
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return True
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self._close_code = 1006
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self._exception = asyncio.TimeoutError()
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return True
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else:
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return False
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async def receive(self, timeout: Optional[float]=None) -> WSMessage:
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if self._reader is None:
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raise RuntimeError('Call .prepare() first')
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loop = self._loop
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assert loop is not None
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while True:
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if self._waiting is not None:
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raise RuntimeError(
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'Concurrent call to receive() is not allowed')
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if self._closed:
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self._conn_lost += 1
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if self._conn_lost >= THRESHOLD_CONNLOST_ACCESS:
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raise RuntimeError('WebSocket connection is closed.')
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return WS_CLOSED_MESSAGE
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elif self._closing:
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return WS_CLOSING_MESSAGE
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try:
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self._waiting = loop.create_future()
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try:
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with async_timeout.timeout(
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timeout or self._receive_timeout, loop=self._loop):
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msg = await self._reader.read()
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self._reset_heartbeat()
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finally:
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waiter = self._waiting
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set_result(waiter, True)
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self._waiting = None
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except (asyncio.CancelledError, asyncio.TimeoutError):
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self._close_code = 1006
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raise
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except EofStream:
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self._close_code = 1000
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await self.close()
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return WSMessage(WSMsgType.CLOSED, None, None)
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except WebSocketError as exc:
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self._close_code = exc.code
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await self.close(code=exc.code)
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return WSMessage(WSMsgType.ERROR, exc, None)
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except Exception as exc:
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self._exception = exc
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self._closing = True
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self._close_code = 1006
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await self.close()
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return WSMessage(WSMsgType.ERROR, exc, None)
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if msg.type == WSMsgType.CLOSE:
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self._closing = True
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self._close_code = msg.data
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if not self._closed and self._autoclose:
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await self.close()
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elif msg.type == WSMsgType.CLOSING:
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self._closing = True
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elif msg.type == WSMsgType.PING and self._autoping:
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await self.pong(msg.data)
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continue
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elif msg.type == WSMsgType.PONG and self._autoping:
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continue
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return msg
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async def receive_str(self, *, timeout: Optional[float]=None) -> str:
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msg = await self.receive(timeout)
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if msg.type != WSMsgType.TEXT:
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raise TypeError(
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"Received message {}:{!r} is not WSMsgType.TEXT".format(
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msg.type, msg.data))
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return msg.data
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async def receive_bytes(self, *, timeout: Optional[float]=None) -> bytes:
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msg = await self.receive(timeout)
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if msg.type != WSMsgType.BINARY:
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raise TypeError(
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"Received message {}:{!r} is not bytes".format(msg.type,
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msg.data))
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return msg.data
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async def receive_json(self, *, loads: JSONDecoder=json.loads,
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timeout: Optional[float]=None) -> Any:
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data = await self.receive_str(timeout=timeout)
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return loads(data)
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async def write(self, data: bytes) -> None:
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raise RuntimeError("Cannot call .write() for websocket")
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def __aiter__(self) -> 'WebSocketResponse':
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return self
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async def __anext__(self) -> WSMessage:
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msg = await self.receive()
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if msg.type in (WSMsgType.CLOSE,
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WSMsgType.CLOSING,
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WSMsgType.CLOSED):
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raise StopAsyncIteration # NOQA
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return msg
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