506 lines
22 KiB
Python
506 lines
22 KiB
Python
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import asyncio
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import urllib
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from . import exceptions
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from . import packet
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from . import server
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from . import asyncio_socket
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class AsyncServer(server.Server):
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"""An Engine.IO server for asyncio.
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This class implements a fully compliant Engine.IO web server 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 async_mode: The asynchronous model to use. See the Deployment
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section in the documentation for a description of the
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available options. Valid async modes are "aiohttp",
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"sanic", "tornado" and "asgi". If this argument is not
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given, "aiohttp" is tried first, followed by "sanic",
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"tornado", and finally "asgi". The first async mode that
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has all its dependencies installed is the one that is
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chosen.
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:param ping_interval: The interval in seconds at which the server pings
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the client. The default is 25 seconds. For advanced
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control, a two element tuple can be given, where
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the first number is the ping interval and the second
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is a grace period added by the server.
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:param ping_timeout: The time in seconds that the client waits for the
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server to respond before disconnecting. The default
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is 20 seconds.
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:param max_http_buffer_size: The maximum size of a message when using the
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polling transport. The default is 1,000,000
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bytes.
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:param allow_upgrades: Whether to allow transport upgrades or not.
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:param http_compression: Whether to compress packages when using the
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polling transport.
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:param compression_threshold: Only compress messages when their byte size
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is greater than this value.
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:param cookie: If set to a string, it is the name of the HTTP cookie the
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server sends back tot he client containing the client
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session id. If set to a dictionary, the ``'name'`` key
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contains the cookie name and other keys define cookie
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attributes, where the value of each attribute can be a
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string, a callable with no arguments, or a boolean. If set
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to ``None`` (the default), a cookie is not sent to the
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client.
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:param cors_allowed_origins: Origin or list of origins that are allowed to
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connect to this server. Only the same origin
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is allowed by default. Set this argument to
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``'*'`` to allow all origins, or to ``[]`` to
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disable CORS handling.
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:param cors_credentials: Whether credentials (cookies, authentication) are
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allowed in requests to this server.
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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``. Note that fatal
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errors are logged even when ``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 async_handlers: If set to ``True``, run message event handlers in
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non-blocking threads. To run handlers synchronously,
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set to ``False``. The default is ``True``.
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:param kwargs: Reserved for future extensions, any additional parameters
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given as keyword arguments will be silently ignored.
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"""
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def is_asyncio_based(self):
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return True
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def async_modes(self):
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return ['aiohttp', 'sanic', 'tornado', 'asgi']
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def attach(self, app, engineio_path='engine.io'):
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"""Attach the Engine.IO server to an application."""
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engineio_path = engineio_path.strip('/')
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self._async['create_route'](app, self, '/{}/'.format(engineio_path))
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async def send(self, sid, data):
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"""Send a message to a client.
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:param sid: The session id of the recipient 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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try:
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socket = self._get_socket(sid)
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except KeyError:
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# the socket is not available
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self.logger.warning('Cannot send to sid %s', sid)
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return
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await socket.send(packet.Packet(packet.MESSAGE, data=data))
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async def get_session(self, sid):
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"""Return the user session for a client.
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:param sid: The session id of the client.
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The return value is a dictionary. Modifications made to this
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dictionary are not guaranteed to be preserved. If you want to modify
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the user session, use the ``session`` context manager instead.
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"""
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socket = self._get_socket(sid)
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return socket.session
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async def save_session(self, sid, session):
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"""Store the user session for a client.
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:param sid: The session id of the client.
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:param session: The session dictionary.
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"""
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socket = self._get_socket(sid)
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socket.session = session
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def session(self, sid):
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"""Return the user session for a client with context manager syntax.
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:param sid: The session id of the client.
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This is a context manager that returns the user session dictionary for
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the client. Any changes that are made to this dictionary inside the
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context manager block are saved back to the session. Example usage::
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@eio.on('connect')
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def on_connect(sid, environ):
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username = authenticate_user(environ)
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if not username:
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return False
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with eio.session(sid) as session:
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session['username'] = username
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@eio.on('message')
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def on_message(sid, msg):
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async with eio.session(sid) as session:
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print('received message from ', session['username'])
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"""
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class _session_context_manager(object):
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def __init__(self, server, sid):
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self.server = server
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self.sid = sid
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self.session = None
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async def __aenter__(self):
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self.session = await self.server.get_session(sid)
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return self.session
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async def __aexit__(self, *args):
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await self.server.save_session(sid, self.session)
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return _session_context_manager(self, sid)
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async def disconnect(self, sid=None):
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"""Disconnect a client.
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:param sid: The session id of the client to close. If this parameter
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is not given, then all clients are closed.
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Note: this method is a coroutine.
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"""
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if sid is not None:
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try:
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socket = self._get_socket(sid)
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except KeyError: # pragma: no cover
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# the socket was already closed or gone
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pass
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else:
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await socket.close()
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if sid in self.sockets: # pragma: no cover
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del self.sockets[sid]
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else:
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await asyncio.wait([client.close()
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for client in self.sockets.values()])
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self.sockets = {}
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async def handle_request(self, *args, **kwargs):
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"""Handle an HTTP request from the client.
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This is the entry point of the Engine.IO application. This function
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returns the HTTP response to deliver to the client.
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Note: this method is a coroutine.
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"""
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translate_request = self._async['translate_request']
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if asyncio.iscoroutinefunction(translate_request):
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environ = await translate_request(*args, **kwargs)
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else:
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environ = translate_request(*args, **kwargs)
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if self.cors_allowed_origins != []:
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# Validate the origin header if present
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# This is important for WebSocket more than for HTTP, since
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# browsers only apply CORS controls to HTTP.
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origin = environ.get('HTTP_ORIGIN')
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if origin:
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allowed_origins = self._cors_allowed_origins(environ)
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if allowed_origins is not None and origin not in \
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allowed_origins:
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self._log_error_once(
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origin + ' is not an accepted origin.', 'bad-origin')
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return await self._make_response(
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self._bad_request(
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origin + ' is not an accepted origin.'),
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environ)
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method = environ['REQUEST_METHOD']
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query = urllib.parse.parse_qs(environ.get('QUERY_STRING', ''))
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sid = query['sid'][0] if 'sid' in query else None
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jsonp = False
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jsonp_index = None
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# make sure the client speaks a compatible Engine.IO version
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sid = query['sid'][0] if 'sid' in query else None
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if sid is None and query.get('EIO') != ['4']:
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self._log_error_once(
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'The client is using an unsupported version of the Socket.IO '
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'or Engine.IO protocols', 'bad-version'
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)
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return await self._make_response(self._bad_request(
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'The client is using an unsupported version of the Socket.IO '
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'or Engine.IO protocols'
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), environ)
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if 'j' in query:
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jsonp = True
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try:
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jsonp_index = int(query['j'][0])
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except (ValueError, KeyError, IndexError):
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# Invalid JSONP index number
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pass
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if jsonp and jsonp_index is None:
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self._log_error_once('Invalid JSONP index number',
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'bad-jsonp-index')
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r = self._bad_request('Invalid JSONP index number')
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elif method == 'GET':
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if sid is None:
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transport = query.get('transport', ['polling'])[0]
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# transport must be one of 'polling' or 'websocket'.
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# if 'websocket', the HTTP_UPGRADE header must match.
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upgrade_header = environ.get('HTTP_UPGRADE').lower() \
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if 'HTTP_UPGRADE' in environ else None
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if transport == 'polling' \
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or transport == upgrade_header == 'websocket':
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r = await self._handle_connect(environ, transport,
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jsonp_index)
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else:
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self._log_error_once('Invalid transport ' + transport,
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'bad-transport')
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r = self._bad_request('Invalid transport ' + transport)
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else:
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if sid not in self.sockets:
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self._log_error_once('Invalid session ' + sid, 'bad-sid')
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r = self._bad_request('Invalid session ' + sid)
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else:
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socket = self._get_socket(sid)
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try:
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packets = await socket.handle_get_request(environ)
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if isinstance(packets, list):
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r = self._ok(packets, jsonp_index=jsonp_index)
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else:
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r = packets
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except exceptions.EngineIOError:
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if sid in self.sockets: # pragma: no cover
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await self.disconnect(sid)
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r = self._bad_request()
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if sid in self.sockets and self.sockets[sid].closed:
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del self.sockets[sid]
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elif method == 'POST':
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if sid is None or sid not in self.sockets:
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self._log_error_once('Invalid session ' + sid, 'bad-sid')
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r = self._bad_request('Invalid session ' + sid)
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else:
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socket = self._get_socket(sid)
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try:
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await socket.handle_post_request(environ)
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r = self._ok(jsonp_index=jsonp_index)
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except exceptions.EngineIOError:
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if sid in self.sockets: # pragma: no cover
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await self.disconnect(sid)
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r = self._bad_request()
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except: # pragma: no cover
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# for any other unexpected errors, we log the error
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# and keep going
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self.logger.exception('post request handler error')
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r = self._ok(jsonp_index=jsonp_index)
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elif method == 'OPTIONS':
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r = self._ok()
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else:
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self.logger.warning('Method %s not supported', method)
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r = self._method_not_found()
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if not isinstance(r, dict):
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return r
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if self.http_compression and \
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len(r['response']) >= self.compression_threshold:
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encodings = [e.split(';')[0].strip() for e in
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environ.get('HTTP_ACCEPT_ENCODING', '').split(',')]
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for encoding in encodings:
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if encoding in self.compression_methods:
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r['response'] = \
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getattr(self, '_' + encoding)(r['response'])
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r['headers'] += [('Content-Encoding', encoding)]
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break
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return await self._make_response(r, environ)
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def start_background_task(self, target, *args, **kwargs):
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"""Start a background task using the appropriate async model.
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This is a utility function that applications can use to start a
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background task using the method that is compatible with the
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selected async mode.
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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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The return value is a ``asyncio.Task`` object.
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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 using the appropriate async
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model.
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This is a utility function that applications can use to put a task to
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sleep without having to worry about using the correct call for the
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selected async mode.
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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, *args, **kwargs):
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"""Create a queue object using the appropriate async model.
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This is a utility function that applications can use to create a queue
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without having to worry about using the correct call for the selected
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async mode. For asyncio based async modes, this returns an instance of
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``asyncio.Queue``.
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"""
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return asyncio.Queue(*args, **kwargs)
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def get_queue_empty_exception(self):
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"""Return the queue empty exception for the appropriate async model.
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This is a utility function that applications can use to work with a
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queue without having to worry about using the correct call for the
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selected async mode. For asyncio based async modes, this returns an
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instance of ``asyncio.QueueEmpty``.
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"""
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return asyncio.QueueEmpty
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def create_event(self, *args, **kwargs):
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"""Create an event object using the appropriate async model.
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This is a utility function that applications can use to create an
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event without having to worry about using the correct call for the
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selected async mode. For asyncio based async modes, this returns
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an instance of ``asyncio.Event``.
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"""
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return asyncio.Event(*args, **kwargs)
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|
async def _make_response(self, response_dict, environ):
|
||
|
|
cors_headers = self._cors_headers(environ)
|
||
|
|
make_response = self._async['make_response']
|
||
|
|
if asyncio.iscoroutinefunction(make_response):
|
||
|
|
response = await make_response(
|
||
|
|
response_dict['status'],
|
||
|
|
response_dict['headers'] + cors_headers,
|
||
|
|
response_dict['response'], environ)
|
||
|
|
else:
|
||
|
|
response = make_response(
|
||
|
|
response_dict['status'],
|
||
|
|
response_dict['headers'] + cors_headers,
|
||
|
|
response_dict['response'], environ)
|
||
|
|
return response
|
||
|
|
|
||
|
|
async def _handle_connect(self, environ, transport, jsonp_index=None):
|
||
|
|
"""Handle a client connection request."""
|
||
|
|
if self.start_service_task:
|
||
|
|
# start the service task to monitor connected clients
|
||
|
|
self.start_service_task = False
|
||
|
|
self.start_background_task(self._service_task)
|
||
|
|
|
||
|
|
sid = self.generate_id()
|
||
|
|
s = asyncio_socket.AsyncSocket(self, sid)
|
||
|
|
self.sockets[sid] = s
|
||
|
|
|
||
|
|
pkt = packet.Packet(
|
||
|
|
packet.OPEN, {'sid': sid,
|
||
|
|
'upgrades': self._upgrades(sid, transport),
|
||
|
|
'pingTimeout': int(self.ping_timeout * 1000),
|
||
|
|
'pingInterval': int(self.ping_interval * 1000)})
|
||
|
|
await s.send(pkt)
|
||
|
|
s.schedule_ping()
|
||
|
|
|
||
|
|
ret = await self._trigger_event('connect', sid, environ,
|
||
|
|
run_async=False)
|
||
|
|
if ret is not None and ret is not True:
|
||
|
|
del self.sockets[sid]
|
||
|
|
self.logger.warning('Application rejected connection')
|
||
|
|
return self._unauthorized(ret or None)
|
||
|
|
|
||
|
|
if transport == 'websocket':
|
||
|
|
ret = await s.handle_get_request(environ)
|
||
|
|
if s.closed and sid in self.sockets:
|
||
|
|
# websocket connection ended, so we are done
|
||
|
|
del self.sockets[sid]
|
||
|
|
return ret
|
||
|
|
else:
|
||
|
|
s.connected = True
|
||
|
|
headers = None
|
||
|
|
if self.cookie:
|
||
|
|
if isinstance(self.cookie, dict):
|
||
|
|
headers = [(
|
||
|
|
'Set-Cookie',
|
||
|
|
self._generate_sid_cookie(sid, self.cookie)
|
||
|
|
)]
|
||
|
|
else:
|
||
|
|
headers = [(
|
||
|
|
'Set-Cookie',
|
||
|
|
self._generate_sid_cookie(sid, {
|
||
|
|
'name': self.cookie, 'path': '/', 'SameSite': 'Lax'
|
||
|
|
})
|
||
|
|
)]
|
||
|
|
try:
|
||
|
|
return self._ok(await s.poll(), headers=headers,
|
||
|
|
jsonp_index=jsonp_index)
|
||
|
|
except exceptions.QueueEmpty:
|
||
|
|
return self._bad_request()
|
||
|
|
|
||
|
|
async def _trigger_event(self, event, *args, **kwargs):
|
||
|
|
"""Invoke an event handler."""
|
||
|
|
run_async = kwargs.pop('run_async', False)
|
||
|
|
ret = None
|
||
|
|
if event in self.handlers:
|
||
|
|
if asyncio.iscoroutinefunction(self.handlers[event]) is True:
|
||
|
|
if run_async:
|
||
|
|
return self.start_background_task(self.handlers[event],
|
||
|
|
*args)
|
||
|
|
else:
|
||
|
|
try:
|
||
|
|
ret = await self.handlers[event](*args)
|
||
|
|
except asyncio.CancelledError: # pragma: no cover
|
||
|
|
pass
|
||
|
|
except:
|
||
|
|
self.logger.exception(event + ' async handler error')
|
||
|
|
if event == 'connect':
|
||
|
|
# if connect handler raised error we reject the
|
||
|
|
# connection
|
||
|
|
return False
|
||
|
|
else:
|
||
|
|
if run_async:
|
||
|
|
async def async_handler():
|
||
|
|
return self.handlers[event](*args)
|
||
|
|
|
||
|
|
return self.start_background_task(async_handler)
|
||
|
|
else:
|
||
|
|
try:
|
||
|
|
ret = self.handlers[event](*args)
|
||
|
|
except:
|
||
|
|
self.logger.exception(event + ' handler error')
|
||
|
|
if event == 'connect':
|
||
|
|
# if connect handler raised error we reject the
|
||
|
|
# connection
|
||
|
|
return False
|
||
|
|
return ret
|
||
|
|
|
||
|
|
async def _service_task(self): # pragma: no cover
|
||
|
|
"""Monitor connected clients and clean up those that time out."""
|
||
|
|
while True:
|
||
|
|
if len(self.sockets) == 0:
|
||
|
|
# nothing to do
|
||
|
|
await self.sleep(self.ping_timeout)
|
||
|
|
continue
|
||
|
|
|
||
|
|
# go through the entire client list in a ping interval cycle
|
||
|
|
sleep_interval = self.ping_timeout / len(self.sockets)
|
||
|
|
|
||
|
|
try:
|
||
|
|
# iterate over the current clients
|
||
|
|
for socket in self.sockets.copy().values():
|
||
|
|
if not socket.closing and not socket.closed:
|
||
|
|
await socket.check_ping_timeout()
|
||
|
|
await self.sleep(sleep_interval)
|
||
|
|
except (
|
||
|
|
SystemExit,
|
||
|
|
KeyboardInterrupt,
|
||
|
|
asyncio.CancelledError,
|
||
|
|
GeneratorExit,
|
||
|
|
):
|
||
|
|
self.logger.info('service task canceled')
|
||
|
|
break
|
||
|
|
except:
|
||
|
|
if asyncio.get_event_loop().is_closed():
|
||
|
|
self.logger.info('event loop is closed, exiting service '
|
||
|
|
'task')
|
||
|
|
break
|
||
|
|
|
||
|
|
# an unexpected exception has occurred, log it and continue
|
||
|
|
self.logger.exception('service task exception')
|