609 lines
25 KiB
Python
609 lines
25 KiB
Python
import asyncio
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import signal
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import ssl
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import threading
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try:
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import aiohttp
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except ImportError: # pragma: no cover
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aiohttp = None
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from . import client
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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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async_signal_handler_set = False
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def async_signal_handler():
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"""SIGINT handler.
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Disconnect all active async clients.
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"""
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async def _handler():
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asyncio.get_event_loop().stop()
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for c in client.connected_clients[:]:
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if c.is_asyncio_based():
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await c.disconnect()
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else: # pragma: no cover
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pass
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asyncio.ensure_future(_handler())
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class AsyncClient(client.Client):
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"""An Engine.IO client for asyncio.
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This class implements a fully compliant Engine.IO web client with support
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for websocket and long-polling transports, compatible with the asyncio
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framework on Python 3.5 or newer.
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:param logger: To enable logging set to ``True`` or pass a logger object to
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use. To disable logging set to ``False``. The default is
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``False``. Note that fatal errors are logged even when
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``logger`` is ``False``.
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:param json: An alternative json module to use for encoding and decoding
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packets. Custom json modules must have ``dumps`` and ``loads``
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functions that are compatible with the standard library
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versions.
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:param request_timeout: A timeout in seconds for requests. The default is
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5 seconds.
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:param http_session: an initialized ``aiohttp.ClientSession`` object to be
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used when sending requests to the server. Use it if
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you need to add special client options such as proxy
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servers, SSL certificates, etc.
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:param ssl_verify: ``True`` to verify SSL certificates, or ``False`` to
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skip SSL certificate verification, allowing
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connections to servers with self signed certificates.
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The default is ``True``.
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"""
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def is_asyncio_based(self):
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return True
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async def connect(self, url, headers=None, transports=None,
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engineio_path='engine.io'):
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"""Connect to an Engine.IO server.
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:param url: The URL of the Engine.IO server. It can include custom
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query string parameters if required by the server.
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:param headers: A dictionary with custom headers to send with the
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connection request.
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:param transports: The list of allowed transports. Valid transports
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are ``'polling'`` and ``'websocket'``. If not
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given, the polling transport is connected first,
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then an upgrade to websocket is attempted.
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:param engineio_path: The endpoint where the Engine.IO server is
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installed. The default value is appropriate for
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most cases.
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Note: this method is a coroutine.
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Example usage::
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eio = engineio.Client()
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await eio.connect('http://localhost:5000')
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"""
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global async_signal_handler_set
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if not async_signal_handler_set and \
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threading.current_thread() == threading.main_thread():
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try:
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asyncio.get_event_loop().add_signal_handler(
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signal.SIGINT, async_signal_handler)
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async_signal_handler_set = True
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except NotImplementedError: # pragma: no cover
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self.logger.warning('Signal handler is unsupported')
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if self.state != 'disconnected':
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raise ValueError('Client is not in a disconnected state')
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valid_transports = ['polling', 'websocket']
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if transports is not None:
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if isinstance(transports, str):
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transports = [transports]
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transports = [transport for transport in transports
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if transport in valid_transports]
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if not transports:
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raise ValueError('No valid transports provided')
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self.transports = transports or valid_transports
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self.queue = self.create_queue()
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return await getattr(self, '_connect_' + self.transports[0])(
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url, headers or {}, engineio_path)
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async def wait(self):
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"""Wait until the connection with the server ends.
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Client applications can use this function to block the main thread
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during the life of the connection.
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Note: this method is a coroutine.
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"""
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if self.read_loop_task:
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await self.read_loop_task
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async def send(self, data):
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"""Send a message to a client.
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:param data: The data to send to the client. Data can be of type
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``str``, ``bytes``, ``list`` or ``dict``. If a ``list``
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or ``dict``, the data will be serialized as JSON.
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Note: this method is a coroutine.
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"""
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await self._send_packet(packet.Packet(packet.MESSAGE, data=data))
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async def disconnect(self, abort=False):
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"""Disconnect from the server.
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:param abort: If set to ``True``, do not wait for background tasks
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associated with the connection to end.
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Note: this method is a coroutine.
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"""
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if self.state == 'connected':
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await self._send_packet(packet.Packet(packet.CLOSE))
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await self.queue.put(None)
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self.state = 'disconnecting'
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await self._trigger_event('disconnect', run_async=False)
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if self.current_transport == 'websocket':
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await self.ws.close()
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if not abort:
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await self.read_loop_task
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self.state = 'disconnected'
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try:
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client.connected_clients.remove(self)
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except ValueError: # pragma: no cover
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pass
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self._reset()
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def start_background_task(self, target, *args, **kwargs):
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"""Start a background task.
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This is a utility function that applications can use to start a
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background task.
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:param target: the target function to execute.
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:param args: arguments to pass to the function.
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:param kwargs: keyword arguments to pass to the function.
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This function returns an object compatible with the `Thread` class in
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the Python standard library. The `start()` method on this object is
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already called by this function.
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Note: this method is a coroutine.
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"""
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return asyncio.ensure_future(target(*args, **kwargs))
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async def sleep(self, seconds=0):
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"""Sleep for the requested amount of time.
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Note: this method is a coroutine.
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"""
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return await asyncio.sleep(seconds)
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def create_queue(self):
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"""Create a queue object."""
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q = asyncio.Queue()
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q.Empty = asyncio.QueueEmpty
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return q
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def create_event(self):
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"""Create an event object."""
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return asyncio.Event()
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def _reset(self):
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if self.http: # pragma: no cover
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asyncio.ensure_future(self.http.close())
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super()._reset()
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async def _connect_polling(self, url, headers, engineio_path):
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"""Establish a long-polling connection to the Engine.IO server."""
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if aiohttp is None: # pragma: no cover
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self.logger.error('aiohttp not installed -- cannot make HTTP '
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'requests!')
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return
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self.base_url = self._get_engineio_url(url, engineio_path, 'polling')
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self.logger.info('Attempting polling connection to ' + self.base_url)
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r = await self._send_request(
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'GET', self.base_url + self._get_url_timestamp(), headers=headers,
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timeout=self.request_timeout)
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if r is None:
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self._reset()
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raise exceptions.ConnectionError(
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'Connection refused by the server')
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if r.status < 200 or r.status >= 300:
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self._reset()
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try:
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arg = await r.json()
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except aiohttp.ClientError:
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arg = None
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raise exceptions.ConnectionError(
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'Unexpected status code {} in server response'.format(
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r.status), arg)
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try:
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p = payload.Payload(encoded_payload=(await r.read()).decode(
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'utf-8'))
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except ValueError:
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raise exceptions.ConnectionError(
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'Unexpected response from server') from None
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open_packet = p.packets[0]
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if open_packet.packet_type != packet.OPEN:
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raise exceptions.ConnectionError(
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'OPEN packet not returned by server')
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self.logger.info(
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'Polling connection accepted with ' + str(open_packet.data))
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self.sid = open_packet.data['sid']
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self.upgrades = open_packet.data['upgrades']
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self.ping_interval = int(open_packet.data['pingInterval']) / 1000.0
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self.ping_timeout = int(open_packet.data['pingTimeout']) / 1000.0
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self.current_transport = 'polling'
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self.base_url += '&sid=' + self.sid
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self.state = 'connected'
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client.connected_clients.append(self)
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await self._trigger_event('connect', run_async=False)
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for pkt in p.packets[1:]:
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await self._receive_packet(pkt)
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if 'websocket' in self.upgrades and 'websocket' in self.transports:
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# attempt to upgrade to websocket
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if await self._connect_websocket(url, headers, engineio_path):
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# upgrade to websocket succeeded, we're done here
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return
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self.write_loop_task = self.start_background_task(self._write_loop)
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self.read_loop_task = self.start_background_task(
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self._read_loop_polling)
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async def _connect_websocket(self, url, headers, engineio_path):
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"""Establish or upgrade to a WebSocket connection with the server."""
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if aiohttp is None: # pragma: no cover
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self.logger.error('aiohttp package not installed')
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return False
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websocket_url = self._get_engineio_url(url, engineio_path,
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'websocket')
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if self.sid:
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self.logger.info(
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'Attempting WebSocket upgrade to ' + websocket_url)
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upgrade = True
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websocket_url += '&sid=' + self.sid
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else:
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upgrade = False
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self.base_url = websocket_url
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self.logger.info(
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'Attempting WebSocket connection to ' + websocket_url)
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if self.http is None or self.http.closed: # pragma: no cover
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self.http = aiohttp.ClientSession()
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# extract any new cookies passed in a header so that they can also be
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# sent the the WebSocket route
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cookies = {}
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for header, value in headers.items():
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if header.lower() == 'cookie':
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cookies = dict(
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[cookie.split('=', 1) for cookie in value.split('; ')])
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del headers[header]
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break
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self.http.cookie_jar.update_cookies(cookies)
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try:
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if not self.ssl_verify:
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ssl_context = ssl.create_default_context()
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ssl_context.check_hostname = False
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ssl_context.verify_mode = ssl.CERT_NONE
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ws = await self.http.ws_connect(
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websocket_url + self._get_url_timestamp(),
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headers=headers, ssl=ssl_context)
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else:
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ws = await self.http.ws_connect(
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websocket_url + self._get_url_timestamp(),
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headers=headers)
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except (aiohttp.client_exceptions.WSServerHandshakeError,
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aiohttp.client_exceptions.ServerConnectionError,
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aiohttp.client_exceptions.ClientConnectionError):
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if upgrade:
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self.logger.warning(
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'WebSocket upgrade failed: connection error')
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return False
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else:
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raise exceptions.ConnectionError('Connection error')
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if upgrade:
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p = packet.Packet(packet.PING, data='probe').encode()
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try:
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await ws.send_str(p)
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except Exception as e: # pragma: no cover
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self.logger.warning(
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'WebSocket upgrade failed: unexpected send exception: %s',
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str(e))
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return False
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try:
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p = (await ws.receive()).data
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except Exception as e: # pragma: no cover
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self.logger.warning(
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'WebSocket upgrade failed: unexpected recv exception: %s',
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str(e))
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return False
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pkt = packet.Packet(encoded_packet=p)
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if pkt.packet_type != packet.PONG or pkt.data != 'probe':
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self.logger.warning(
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'WebSocket upgrade failed: no PONG packet')
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return False
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p = packet.Packet(packet.UPGRADE).encode()
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try:
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await ws.send_str(p)
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except Exception as e: # pragma: no cover
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self.logger.warning(
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'WebSocket upgrade failed: unexpected send exception: %s',
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str(e))
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return False
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self.current_transport = 'websocket'
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self.logger.info('WebSocket upgrade was successful')
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else:
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try:
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p = (await ws.receive()).data
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except Exception as e: # pragma: no cover
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raise exceptions.ConnectionError(
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'Unexpected recv exception: ' + str(e))
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open_packet = packet.Packet(encoded_packet=p)
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if open_packet.packet_type != packet.OPEN:
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raise exceptions.ConnectionError('no OPEN packet')
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self.logger.info(
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'WebSocket connection accepted with ' + str(open_packet.data))
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self.sid = open_packet.data['sid']
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self.upgrades = open_packet.data['upgrades']
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self.ping_interval = int(open_packet.data['pingInterval']) / 1000.0
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self.ping_timeout = int(open_packet.data['pingTimeout']) / 1000.0
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self.current_transport = 'websocket'
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self.state = 'connected'
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client.connected_clients.append(self)
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await self._trigger_event('connect', run_async=False)
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self.ws = ws
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self.write_loop_task = self.start_background_task(self._write_loop)
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self.read_loop_task = self.start_background_task(
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self._read_loop_websocket)
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return True
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async def _receive_packet(self, pkt):
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"""Handle incoming packets from the server."""
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packet_name = packet.packet_names[pkt.packet_type] \
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if pkt.packet_type < len(packet.packet_names) else 'UNKNOWN'
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self.logger.info(
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'Received packet %s data %s', packet_name,
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pkt.data if not isinstance(pkt.data, bytes) else '<binary>')
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if pkt.packet_type == packet.MESSAGE:
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await self._trigger_event('message', pkt.data, run_async=True)
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elif pkt.packet_type == packet.PING:
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await self._send_packet(packet.Packet(packet.PONG, pkt.data))
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elif pkt.packet_type == packet.CLOSE:
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await self.disconnect(abort=True)
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elif pkt.packet_type == packet.NOOP:
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pass
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else:
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self.logger.error('Received unexpected packet of type %s',
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pkt.packet_type)
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async def _send_packet(self, pkt):
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"""Queue a packet to be sent to the server."""
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if self.state != 'connected':
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return
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await self.queue.put(pkt)
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self.logger.info(
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'Sending packet %s data %s',
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packet.packet_names[pkt.packet_type],
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pkt.data if not isinstance(pkt.data, bytes) else '<binary>')
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async def _send_request(
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self, method, url, headers=None, body=None,
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timeout=None): # pragma: no cover
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if self.http is None or self.http.closed:
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self.http = aiohttp.ClientSession()
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http_method = getattr(self.http, method.lower())
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try:
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if not self.ssl_verify:
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return await http_method(
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url, headers=headers, data=body,
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timeout=aiohttp.ClientTimeout(total=timeout), ssl=False)
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else:
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return await http_method(
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url, headers=headers, data=body,
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timeout=aiohttp.ClientTimeout(total=timeout))
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except (aiohttp.ClientError, asyncio.TimeoutError) as exc:
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self.logger.info('HTTP %s request to %s failed with error %s.',
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method, url, exc)
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async def _trigger_event(self, event, *args, **kwargs):
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"""Invoke an event handler."""
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run_async = kwargs.pop('run_async', False)
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ret = None
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if event in self.handlers:
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if asyncio.iscoroutinefunction(self.handlers[event]) is True:
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if run_async:
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return self.start_background_task(self.handlers[event],
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*args)
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else:
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try:
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ret = await self.handlers[event](*args)
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except asyncio.CancelledError: # pragma: no cover
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pass
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except:
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self.logger.exception(event + ' async handler error')
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if event == 'connect':
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# if connect handler raised error we reject the
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# connection
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return False
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else:
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if run_async:
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async def async_handler():
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return self.handlers[event](*args)
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return self.start_background_task(async_handler)
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else:
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try:
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ret = self.handlers[event](*args)
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except:
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self.logger.exception(event + ' handler error')
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if event == 'connect':
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# if connect handler raised error we reject the
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# connection
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return False
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return ret
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async def _read_loop_polling(self):
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"""Read packets by polling the Engine.IO server."""
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while self.state == 'connected':
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self.logger.info(
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'Sending polling GET request to ' + self.base_url)
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r = await self._send_request(
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'GET', self.base_url + self._get_url_timestamp(),
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timeout=max(self.ping_interval, self.ping_timeout) + 5)
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if r is None:
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self.logger.warning(
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'Connection refused by the server, aborting')
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await self.queue.put(None)
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break
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if r.status < 200 or r.status >= 300:
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self.logger.warning('Unexpected status code %s in server '
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'response, aborting', r.status)
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await self.queue.put(None)
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break
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try:
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p = payload.Payload(encoded_payload=(await r.read()).decode(
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'utf-8'))
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except ValueError:
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self.logger.warning(
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'Unexpected packet from server, aborting')
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await self.queue.put(None)
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break
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for pkt in p.packets:
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await self._receive_packet(pkt)
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self.logger.info('Waiting for write loop task to end')
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await self.write_loop_task
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if self.state == 'connected':
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await self._trigger_event('disconnect', run_async=False)
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try:
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client.connected_clients.remove(self)
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except ValueError: # pragma: no cover
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pass
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self._reset()
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self.logger.info('Exiting read loop task')
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async def _read_loop_websocket(self):
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"""Read packets from the Engine.IO WebSocket connection."""
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while self.state == 'connected':
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p = None
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try:
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p = await asyncio.wait_for(
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self.ws.receive(),
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timeout=self.ping_interval + self.ping_timeout)
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p = p.data
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if p is None: # pragma: no cover
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break # the connection is broken
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except asyncio.TimeoutError:
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|
self.logger.warning(
|
|
'Server has stopped communicating, aborting')
|
|
await self.queue.put(None)
|
|
break
|
|
except aiohttp.client_exceptions.ServerDisconnectedError:
|
|
self.logger.info(
|
|
'Read loop: WebSocket connection was closed, aborting')
|
|
await self.queue.put(None)
|
|
break
|
|
except Exception as e:
|
|
self.logger.info(
|
|
'Unexpected error receiving packet: "%s", aborting',
|
|
str(e))
|
|
await self.queue.put(None)
|
|
break
|
|
try:
|
|
pkt = packet.Packet(encoded_packet=p)
|
|
except Exception as e: # pragma: no cover
|
|
self.logger.info(
|
|
'Unexpected error decoding packet: "%s", aborting', str(e))
|
|
await self.queue.put(None)
|
|
break
|
|
await self._receive_packet(pkt)
|
|
|
|
self.logger.info('Waiting for write loop task to end')
|
|
await self.write_loop_task
|
|
if self.state == 'connected':
|
|
await self._trigger_event('disconnect', run_async=False)
|
|
try:
|
|
client.connected_clients.remove(self)
|
|
except ValueError: # pragma: no cover
|
|
pass
|
|
self._reset()
|
|
self.logger.info('Exiting read loop task')
|
|
|
|
async def _write_loop(self):
|
|
"""This background task sends packages to the server as they are
|
|
pushed to the send queue.
|
|
"""
|
|
while self.state == 'connected':
|
|
# to simplify the timeout handling, use the maximum of the
|
|
# ping interval and ping timeout as timeout, with an extra 5
|
|
# seconds grace period
|
|
timeout = max(self.ping_interval, self.ping_timeout) + 5
|
|
packets = None
|
|
try:
|
|
packets = [await asyncio.wait_for(self.queue.get(), timeout)]
|
|
except (self.queue.Empty, asyncio.TimeoutError,
|
|
asyncio.CancelledError):
|
|
self.logger.error('packet queue is empty, aborting')
|
|
break
|
|
if packets == [None]:
|
|
self.queue.task_done()
|
|
packets = []
|
|
else:
|
|
while True:
|
|
try:
|
|
packets.append(self.queue.get_nowait())
|
|
except self.queue.Empty:
|
|
break
|
|
if packets[-1] is None:
|
|
packets = packets[:-1]
|
|
self.queue.task_done()
|
|
break
|
|
if not packets:
|
|
# empty packet list returned -> connection closed
|
|
break
|
|
if self.current_transport == 'polling':
|
|
p = payload.Payload(packets=packets)
|
|
r = await self._send_request(
|
|
'POST', self.base_url, body=p.encode(),
|
|
headers={'Content-Type': 'application/octet-stream'},
|
|
timeout=self.request_timeout)
|
|
for pkt in packets:
|
|
self.queue.task_done()
|
|
if r is None:
|
|
self.logger.warning(
|
|
'Connection refused by the server, aborting')
|
|
break
|
|
if r.status < 200 or r.status >= 300:
|
|
self.logger.warning('Unexpected status code %s in server '
|
|
'response, aborting', r.status)
|
|
self._reset()
|
|
break
|
|
else:
|
|
# websocket
|
|
try:
|
|
for pkt in packets:
|
|
if pkt.binary:
|
|
await self.ws.send_bytes(pkt.encode())
|
|
else:
|
|
await self.ws.send_str(pkt.encode())
|
|
self.queue.task_done()
|
|
except (aiohttp.client_exceptions.ServerDisconnectedError,
|
|
BrokenPipeError, OSError):
|
|
self.logger.info(
|
|
'Write loop: WebSocket connection was closed, '
|
|
'aborting')
|
|
break
|
|
self.logger.info('Exiting write loop task')
|