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252 lines
10 KiB
252 lines
10 KiB
import asyncio
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import sys
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import time
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from . import exceptions
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from . import packet
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from . import payload
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from . import socket
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class AsyncSocket(socket.Socket):
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async def poll(self):
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"""Wait for packets to send to the client."""
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try:
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packets = [await asyncio.wait_for(
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self.queue.get(),
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self.server.ping_interval + self.server.ping_timeout)]
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self.queue.task_done()
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except (asyncio.TimeoutError, asyncio.CancelledError):
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raise exceptions.QueueEmpty()
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if packets == [None]:
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return []
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while True:
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try:
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pkt = self.queue.get_nowait()
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self.queue.task_done()
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if pkt is None:
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self.queue.put_nowait(None)
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break
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packets.append(pkt)
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except asyncio.QueueEmpty:
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break
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return packets
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async def receive(self, pkt):
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"""Receive packet from the client."""
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self.server.logger.info('%s: Received packet %s data %s',
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self.sid, packet.packet_names[pkt.packet_type],
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pkt.data if not isinstance(pkt.data, bytes)
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else '<binary>')
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if pkt.packet_type == packet.PONG:
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self.schedule_ping()
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elif pkt.packet_type == packet.MESSAGE:
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await self.server._trigger_event(
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'message', self.sid, pkt.data,
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run_async=self.server.async_handlers)
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elif pkt.packet_type == packet.UPGRADE:
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await self.send(packet.Packet(packet.NOOP))
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elif pkt.packet_type == packet.CLOSE:
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await self.close(wait=False, abort=True)
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else:
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raise exceptions.UnknownPacketError()
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async def check_ping_timeout(self):
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"""Make sure the client is still sending pings."""
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if self.closed:
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raise exceptions.SocketIsClosedError()
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if self.last_ping and \
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time.time() - self.last_ping > self.server.ping_timeout:
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self.server.logger.info('%s: Client is gone, closing socket',
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self.sid)
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# Passing abort=False here will cause close() to write a
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# CLOSE packet. This has the effect of updating half-open sockets
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# to their correct state of disconnected
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await self.close(wait=False, abort=False)
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return False
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return True
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async def send(self, pkt):
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"""Send a packet to the client."""
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if not await self.check_ping_timeout():
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return
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else:
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await self.queue.put(pkt)
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self.server.logger.info('%s: Sending packet %s data %s',
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self.sid, packet.packet_names[pkt.packet_type],
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pkt.data if not isinstance(pkt.data, bytes)
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else '<binary>')
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async def handle_get_request(self, environ):
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"""Handle a long-polling GET request from the client."""
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connections = [
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s.strip()
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for s in environ.get('HTTP_CONNECTION', '').lower().split(',')]
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transport = environ.get('HTTP_UPGRADE', '').lower()
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if 'upgrade' in connections and transport in self.upgrade_protocols:
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self.server.logger.info('%s: Received request to upgrade to %s',
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self.sid, transport)
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return await getattr(self, '_upgrade_' + transport)(environ)
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if self.upgrading or self.upgraded:
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# we are upgrading to WebSocket, do not return any more packets
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# through the polling endpoint
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return [packet.Packet(packet.NOOP)]
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try:
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packets = await self.poll()
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except exceptions.QueueEmpty:
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exc = sys.exc_info()
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await self.close(wait=False)
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raise exc[1].with_traceback(exc[2])
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return packets
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async def handle_post_request(self, environ):
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"""Handle a long-polling POST request from the client."""
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length = int(environ.get('CONTENT_LENGTH', '0'))
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if length > self.server.max_http_buffer_size:
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raise exceptions.ContentTooLongError()
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else:
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body = (await environ['wsgi.input'].read(length)).decode('utf-8')
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p = payload.Payload(encoded_payload=body)
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for pkt in p.packets:
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await self.receive(pkt)
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async def close(self, wait=True, abort=False):
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"""Close the socket connection."""
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if not self.closed and not self.closing:
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self.closing = True
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await self.server._trigger_event('disconnect', self.sid)
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if not abort:
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await self.send(packet.Packet(packet.CLOSE))
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self.closed = True
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if wait:
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await self.queue.join()
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def schedule_ping(self):
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async def send_ping():
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self.last_ping = None
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await asyncio.sleep(self.server.ping_interval)
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if not self.closing and not self.closed:
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self.last_ping = time.time()
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await self.send(packet.Packet(packet.PING))
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self.server.start_background_task(send_ping)
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async def _upgrade_websocket(self, environ):
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"""Upgrade the connection from polling to websocket."""
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if self.upgraded:
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raise IOError('Socket has been upgraded already')
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if self.server._async['websocket'] is None:
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# the selected async mode does not support websocket
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return self.server._bad_request()
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ws = self.server._async['websocket'](self._websocket_handler)
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return await ws(environ)
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async def _websocket_handler(self, ws):
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"""Engine.IO handler for websocket transport."""
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async def websocket_wait():
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data = await ws.wait()
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if data and len(data) > self.server.max_http_buffer_size:
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raise ValueError('packet is too large')
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return data
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if self.connected:
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# the socket was already connected, so this is an upgrade
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self.upgrading = True # hold packet sends during the upgrade
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try:
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pkt = await websocket_wait()
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except IOError: # pragma: no cover
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return
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decoded_pkt = packet.Packet(encoded_packet=pkt)
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if decoded_pkt.packet_type != packet.PING or \
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decoded_pkt.data != 'probe':
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self.server.logger.info(
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'%s: Failed websocket upgrade, no PING packet', self.sid)
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self.upgrading = False
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return
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await ws.send(packet.Packet(packet.PONG, data='probe').encode())
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await self.queue.put(packet.Packet(packet.NOOP)) # end poll
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try:
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pkt = await websocket_wait()
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except IOError: # pragma: no cover
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self.upgrading = False
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return
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decoded_pkt = packet.Packet(encoded_packet=pkt)
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if decoded_pkt.packet_type != packet.UPGRADE:
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self.upgraded = False
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self.server.logger.info(
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('%s: Failed websocket upgrade, expected UPGRADE packet, '
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'received %s instead.'),
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self.sid, pkt)
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self.upgrading = False
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return
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self.upgraded = True
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self.upgrading = False
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else:
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self.connected = True
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self.upgraded = True
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# start separate writer thread
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async def writer():
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while True:
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packets = None
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try:
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packets = await self.poll()
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except exceptions.QueueEmpty:
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break
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if not packets:
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# empty packet list returned -> connection closed
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break
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try:
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for pkt in packets:
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await ws.send(pkt.encode())
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except:
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break
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writer_task = asyncio.ensure_future(writer())
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self.server.logger.info(
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'%s: Upgrade to websocket successful', self.sid)
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while True:
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p = None
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wait_task = asyncio.ensure_future(websocket_wait())
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try:
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p = await asyncio.wait_for(
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wait_task,
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self.server.ping_interval + self.server.ping_timeout)
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except asyncio.CancelledError: # pragma: no cover
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# there is a bug (https://bugs.python.org/issue30508) in
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# asyncio that causes a "Task exception never retrieved" error
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# to appear when wait_task raises an exception before it gets
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# cancelled. Calling wait_task.exception() prevents the error
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# from being issued in Python 3.6, but causes other errors in
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# other versions, so we run it with all errors suppressed and
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# hope for the best.
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try:
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wait_task.exception()
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except:
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pass
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break
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except:
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break
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if p is None:
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# connection closed by client
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break
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pkt = packet.Packet(encoded_packet=p)
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try:
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await self.receive(pkt)
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except exceptions.UnknownPacketError: # pragma: no cover
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pass
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except exceptions.SocketIsClosedError: # pragma: no cover
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self.server.logger.info('Receive error -- socket is closed')
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break
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except: # pragma: no cover
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# if we get an unexpected exception we log the error and exit
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# the connection properly
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self.server.logger.exception('Unknown receive error')
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await self.queue.put(None) # unlock the writer task so it can exit
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await asyncio.wait_for(writer_task, timeout=None)
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await self.close(wait=False, abort=True)
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