import asyncio import base64 import binascii import hashlib import json import async_timeout import attr from multidict import CIMultiDict from . import hdrs from .helpers import call_later, set_result from .http import (WS_CLOSED_MESSAGE, WS_CLOSING_MESSAGE, WS_KEY, WebSocketError, WebSocketReader, WebSocketWriter, WSMessage, WSMsgType, ws_ext_gen, ws_ext_parse) from .log import ws_logger from .streams import EofStream, FlowControlDataQueue from .web_exceptions import HTTPBadRequest, HTTPException, HTTPMethodNotAllowed from .web_response import StreamResponse __all__ = ('WebSocketResponse', 'WebSocketReady', 'WSMsgType',) THRESHOLD_CONNLOST_ACCESS = 5 @attr.s(frozen=True, slots=True) class WebSocketReady: ok = attr.ib(type=bool) protocol = attr.ib(type=str) def __bool__(self): return self.ok class WebSocketResponse(StreamResponse): def __init__(self, *, timeout=10.0, receive_timeout=None, autoclose=True, autoping=True, heartbeat=None, protocols=(), compress=True, max_msg_size=4*1024*1024): super().__init__(status=101) self._protocols = protocols self._ws_protocol = None self._writer = None self._reader = None self._closed = False self._closing = False self._conn_lost = 0 self._close_code = None self._loop = None self._waiting = None self._exception = None self._timeout = timeout self._receive_timeout = receive_timeout self._autoclose = autoclose self._autoping = autoping self._heartbeat = heartbeat self._heartbeat_cb = None if heartbeat is not None: self._pong_heartbeat = heartbeat / 2.0 self._pong_response_cb = None self._compress = compress self._max_msg_size = max_msg_size def _cancel_heartbeat(self): 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): self._cancel_heartbeat() if self._heartbeat is not None: self._heartbeat_cb = call_later( self._send_heartbeat, self._heartbeat, self._loop) def _send_heartbeat(self): if self._heartbeat is not None and not self._closed: # 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()) 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): if self._req is not None and self._req.transport is not None: self._closed = True self._close_code = 1006 self._exception = asyncio.TimeoutError() self._req.transport.close() async def prepare(self, request): # 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) self._post_start(request, protocol, writer) await payload_writer.drain() return payload_writer def _handshake(self, request): headers = request.headers if request.method != hdrs.METH_GET: raise HTTPMethodNotAllowed(request.method, [hdrs.METH_GET]) 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='Unsupported version: {}'.format(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='Handshake error: {!r}'.format(key)) except binascii.Error: raise HTTPBadRequest( text='Handshake error: {!r}'.format(key)) from None accept_val = base64.b64encode( hashlib.sha1(key.encode() + WS_KEY).digest()).decode() response_headers = CIMultiDict({hdrs.UPGRADE: 'websocket', hdrs.CONNECTION: 'upgrade', hdrs.TRANSFER_ENCODING: 'chunked', hdrs.SEC_WEBSOCKET_ACCEPT: accept_val}) notakeover = False compress = self._compress if 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) def _pre_start(self, request): self._loop = request.loop headers, protocol, compress, notakeover = self._handshake( request) self._reset_heartbeat() self.set_status(101) self.headers.update(headers) self.force_close() self._compress = compress writer = WebSocketWriter(request._protocol, request._protocol.transport, compress=compress, notakeover=notakeover) return protocol, writer def _post_start(self, request, protocol, writer): self._ws_protocol = protocol self._writer = writer self._reader = FlowControlDataQueue( request._protocol, limit=2 ** 16, loop=self._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): 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): return self._closed @property def close_code(self): return self._close_code @property def ws_protocol(self): return self._ws_protocol @property def compress(self): return self._compress def exception(self): return self._exception async def ping(self, message='b'): if self._writer is None: raise RuntimeError('Call .prepare() first') await self._writer.ping(message) async def pong(self, message='b'): # unsolicited pong if self._writer is None: raise RuntimeError('Call .prepare() first') await self._writer.pong(message) async def send_str(self, data, compress=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, compress=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, compress=None, *, dumps=json.dumps): await self.send_str(dumps(data), compress=compress) async def write_eof(self): 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=1000, message=b''): if self._writer is None: raise RuntimeError('Call .prepare() first') self._cancel_heartbeat() # we need to break `receive()` cycle first, # `close()` may be called from different task if self._waiting is not None and not self._closed: self._reader.feed_data(WS_CLOSING_MESSAGE, 0) await self._waiting if not self._closed: self._closed = True try: await self._writer.close(code, message) await self._payload_writer.drain() except (asyncio.CancelledError, asyncio.TimeoutError): self._close_code = 1006 raise except Exception as exc: self._close_code = 1006 self._exception = exc return True if self._closing: return True try: with async_timeout.timeout(self._timeout, loop=self._loop): msg = await self._reader.read() except asyncio.CancelledError: self._close_code = 1006 raise except Exception as exc: self._close_code = 1006 self._exception = exc return True if msg.type == WSMsgType.CLOSE: self._close_code = msg.data return True self._close_code = 1006 self._exception = asyncio.TimeoutError() return True else: return False async def receive(self, timeout=None): if self._reader is None: raise RuntimeError('Call .prepare() first') 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 = self._loop.create_future() try: with async_timeout.timeout( timeout or self._receive_timeout, loop=self._loop): 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 = 1006 raise except EofStream: self._close_code = 1000 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 = 1006 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=None): 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 msg.data async def receive_bytes(self, *, timeout=None): msg = await self.receive(timeout) if msg.type != WSMsgType.BINARY: raise TypeError( "Received message {}:{!r} is not bytes".format(msg.type, msg.data)) return msg.data async def receive_json(self, *, loads=json.loads, timeout=None): data = await self.receive_str(timeout=timeout) return loads(data) async def write(self, data): raise RuntimeError("Cannot call .write() for websocket") def __aiter__(self): return self async def __anext__(self): msg = await self.receive() if msg.type in (WSMsgType.CLOSE, WSMsgType.CLOSING, WSMsgType.CLOSED): raise StopAsyncIteration # NOQA return msg