506 lines
22 KiB
Python
506 lines
22 KiB
Python
import asyncio
|
|
import urllib
|
|
|
|
from . import exceptions
|
|
from . import packet
|
|
from . import server
|
|
from . import asyncio_socket
|
|
|
|
|
|
class AsyncServer(server.Server):
|
|
"""An Engine.IO server for asyncio.
|
|
|
|
This class implements a fully compliant Engine.IO web server with support
|
|
for websocket and long-polling transports, compatible with the asyncio
|
|
framework on Python 3.5 or newer.
|
|
|
|
:param async_mode: The asynchronous model to use. See the Deployment
|
|
section in the documentation for a description of the
|
|
available options. Valid async modes are "aiohttp",
|
|
"sanic", "tornado" and "asgi". If this argument is not
|
|
given, "aiohttp" is tried first, followed by "sanic",
|
|
"tornado", and finally "asgi". The first async mode that
|
|
has all its dependencies installed is the one that is
|
|
chosen.
|
|
:param ping_interval: The interval in seconds at which the server pings
|
|
the client. The default is 25 seconds. For advanced
|
|
control, a two element tuple can be given, where
|
|
the first number is the ping interval and the second
|
|
is a grace period added by the server.
|
|
:param ping_timeout: The time in seconds that the client waits for the
|
|
server to respond before disconnecting. The default
|
|
is 20 seconds.
|
|
:param max_http_buffer_size: The maximum size of a message when using the
|
|
polling transport. The default is 1,000,000
|
|
bytes.
|
|
:param allow_upgrades: Whether to allow transport upgrades or not.
|
|
:param http_compression: Whether to compress packages when using the
|
|
polling transport.
|
|
:param compression_threshold: Only compress messages when their byte size
|
|
is greater than this value.
|
|
:param cookie: If set to a string, it is the name of the HTTP cookie the
|
|
server sends back tot he client containing the client
|
|
session id. If set to a dictionary, the ``'name'`` key
|
|
contains the cookie name and other keys define cookie
|
|
attributes, where the value of each attribute can be a
|
|
string, a callable with no arguments, or a boolean. If set
|
|
to ``None`` (the default), a cookie is not sent to the
|
|
client.
|
|
:param cors_allowed_origins: Origin or list of origins that are allowed to
|
|
connect to this server. Only the same origin
|
|
is allowed by default. Set this argument to
|
|
``'*'`` to allow all origins, or to ``[]`` to
|
|
disable CORS handling.
|
|
:param cors_credentials: Whether credentials (cookies, authentication) are
|
|
allowed in requests to this server.
|
|
:param logger: To enable logging set to ``True`` or pass a logger object to
|
|
use. To disable logging set to ``False``. Note that fatal
|
|
errors are logged even when ``logger`` is ``False``.
|
|
:param json: An alternative json module to use for encoding and decoding
|
|
packets. Custom json modules must have ``dumps`` and ``loads``
|
|
functions that are compatible with the standard library
|
|
versions.
|
|
:param async_handlers: If set to ``True``, run message event handlers in
|
|
non-blocking threads. To run handlers synchronously,
|
|
set to ``False``. The default is ``True``.
|
|
:param kwargs: Reserved for future extensions, any additional parameters
|
|
given as keyword arguments will be silently ignored.
|
|
"""
|
|
def is_asyncio_based(self):
|
|
return True
|
|
|
|
def async_modes(self):
|
|
return ['aiohttp', 'sanic', 'tornado', 'asgi']
|
|
|
|
def attach(self, app, engineio_path='engine.io'):
|
|
"""Attach the Engine.IO server to an application."""
|
|
engineio_path = engineio_path.strip('/')
|
|
self._async['create_route'](app, self, '/{}/'.format(engineio_path))
|
|
|
|
async def send(self, sid, data):
|
|
"""Send a message to a client.
|
|
|
|
:param sid: The session id of the recipient client.
|
|
:param data: The data to send to the client. Data can be of type
|
|
``str``, ``bytes``, ``list`` or ``dict``. If a ``list``
|
|
or ``dict``, the data will be serialized as JSON.
|
|
|
|
Note: this method is a coroutine.
|
|
"""
|
|
try:
|
|
socket = self._get_socket(sid)
|
|
except KeyError:
|
|
# the socket is not available
|
|
self.logger.warning('Cannot send to sid %s', sid)
|
|
return
|
|
await socket.send(packet.Packet(packet.MESSAGE, data=data))
|
|
|
|
async def get_session(self, sid):
|
|
"""Return the user session for a client.
|
|
|
|
:param sid: The session id of the client.
|
|
|
|
The return value is a dictionary. Modifications made to this
|
|
dictionary are not guaranteed to be preserved. If you want to modify
|
|
the user session, use the ``session`` context manager instead.
|
|
"""
|
|
socket = self._get_socket(sid)
|
|
return socket.session
|
|
|
|
async def save_session(self, sid, session):
|
|
"""Store the user session for a client.
|
|
|
|
:param sid: The session id of the client.
|
|
:param session: The session dictionary.
|
|
"""
|
|
socket = self._get_socket(sid)
|
|
socket.session = session
|
|
|
|
def session(self, sid):
|
|
"""Return the user session for a client with context manager syntax.
|
|
|
|
:param sid: The session id of the client.
|
|
|
|
This is a context manager that returns the user session dictionary for
|
|
the client. Any changes that are made to this dictionary inside the
|
|
context manager block are saved back to the session. Example usage::
|
|
|
|
@eio.on('connect')
|
|
def on_connect(sid, environ):
|
|
username = authenticate_user(environ)
|
|
if not username:
|
|
return False
|
|
with eio.session(sid) as session:
|
|
session['username'] = username
|
|
|
|
@eio.on('message')
|
|
def on_message(sid, msg):
|
|
async with eio.session(sid) as session:
|
|
print('received message from ', session['username'])
|
|
"""
|
|
class _session_context_manager(object):
|
|
def __init__(self, server, sid):
|
|
self.server = server
|
|
self.sid = sid
|
|
self.session = None
|
|
|
|
async def __aenter__(self):
|
|
self.session = await self.server.get_session(sid)
|
|
return self.session
|
|
|
|
async def __aexit__(self, *args):
|
|
await self.server.save_session(sid, self.session)
|
|
|
|
return _session_context_manager(self, sid)
|
|
|
|
async def disconnect(self, sid=None):
|
|
"""Disconnect a client.
|
|
|
|
:param sid: The session id of the client to close. If this parameter
|
|
is not given, then all clients are closed.
|
|
|
|
Note: this method is a coroutine.
|
|
"""
|
|
if sid is not None:
|
|
try:
|
|
socket = self._get_socket(sid)
|
|
except KeyError: # pragma: no cover
|
|
# the socket was already closed or gone
|
|
pass
|
|
else:
|
|
await socket.close()
|
|
if sid in self.sockets: # pragma: no cover
|
|
del self.sockets[sid]
|
|
else:
|
|
await asyncio.wait([client.close()
|
|
for client in self.sockets.values()])
|
|
self.sockets = {}
|
|
|
|
async def handle_request(self, *args, **kwargs):
|
|
"""Handle an HTTP request from the client.
|
|
|
|
This is the entry point of the Engine.IO application. This function
|
|
returns the HTTP response to deliver to the client.
|
|
|
|
Note: this method is a coroutine.
|
|
"""
|
|
translate_request = self._async['translate_request']
|
|
if asyncio.iscoroutinefunction(translate_request):
|
|
environ = await translate_request(*args, **kwargs)
|
|
else:
|
|
environ = translate_request(*args, **kwargs)
|
|
|
|
if self.cors_allowed_origins != []:
|
|
# Validate the origin header if present
|
|
# This is important for WebSocket more than for HTTP, since
|
|
# browsers only apply CORS controls to HTTP.
|
|
origin = environ.get('HTTP_ORIGIN')
|
|
if origin:
|
|
allowed_origins = self._cors_allowed_origins(environ)
|
|
if allowed_origins is not None and origin not in \
|
|
allowed_origins:
|
|
self._log_error_once(
|
|
origin + ' is not an accepted origin.', 'bad-origin')
|
|
return await self._make_response(
|
|
self._bad_request(
|
|
origin + ' is not an accepted origin.'),
|
|
environ)
|
|
|
|
method = environ['REQUEST_METHOD']
|
|
query = urllib.parse.parse_qs(environ.get('QUERY_STRING', ''))
|
|
|
|
sid = query['sid'][0] if 'sid' in query else None
|
|
jsonp = False
|
|
jsonp_index = None
|
|
|
|
# make sure the client speaks a compatible Engine.IO version
|
|
sid = query['sid'][0] if 'sid' in query else None
|
|
if sid is None and query.get('EIO') != ['4']:
|
|
self._log_error_once(
|
|
'The client is using an unsupported version of the Socket.IO '
|
|
'or Engine.IO protocols', 'bad-version'
|
|
)
|
|
return await self._make_response(self._bad_request(
|
|
'The client is using an unsupported version of the Socket.IO '
|
|
'or Engine.IO protocols'
|
|
), environ)
|
|
|
|
if 'j' in query:
|
|
jsonp = True
|
|
try:
|
|
jsonp_index = int(query['j'][0])
|
|
except (ValueError, KeyError, IndexError):
|
|
# Invalid JSONP index number
|
|
pass
|
|
|
|
if jsonp and jsonp_index is None:
|
|
self._log_error_once('Invalid JSONP index number',
|
|
'bad-jsonp-index')
|
|
r = self._bad_request('Invalid JSONP index number')
|
|
elif method == 'GET':
|
|
if sid is None:
|
|
transport = query.get('transport', ['polling'])[0]
|
|
# transport must be one of 'polling' or 'websocket'.
|
|
# if 'websocket', the HTTP_UPGRADE header must match.
|
|
upgrade_header = environ.get('HTTP_UPGRADE').lower() \
|
|
if 'HTTP_UPGRADE' in environ else None
|
|
if transport == 'polling' \
|
|
or transport == upgrade_header == 'websocket':
|
|
r = await self._handle_connect(environ, transport,
|
|
jsonp_index)
|
|
else:
|
|
self._log_error_once('Invalid transport ' + transport,
|
|
'bad-transport')
|
|
r = self._bad_request('Invalid transport ' + transport)
|
|
else:
|
|
if sid not in self.sockets:
|
|
self._log_error_once('Invalid session ' + sid, 'bad-sid')
|
|
r = self._bad_request('Invalid session ' + sid)
|
|
else:
|
|
socket = self._get_socket(sid)
|
|
try:
|
|
packets = await socket.handle_get_request(environ)
|
|
if isinstance(packets, list):
|
|
r = self._ok(packets, jsonp_index=jsonp_index)
|
|
else:
|
|
r = packets
|
|
except exceptions.EngineIOError:
|
|
if sid in self.sockets: # pragma: no cover
|
|
await self.disconnect(sid)
|
|
r = self._bad_request()
|
|
if sid in self.sockets and self.sockets[sid].closed:
|
|
del self.sockets[sid]
|
|
elif method == 'POST':
|
|
if sid is None or sid not in self.sockets:
|
|
self._log_error_once('Invalid session ' + sid, 'bad-sid')
|
|
r = self._bad_request('Invalid session ' + sid)
|
|
else:
|
|
socket = self._get_socket(sid)
|
|
try:
|
|
await socket.handle_post_request(environ)
|
|
r = self._ok(jsonp_index=jsonp_index)
|
|
except exceptions.EngineIOError:
|
|
if sid in self.sockets: # pragma: no cover
|
|
await self.disconnect(sid)
|
|
r = self._bad_request()
|
|
except: # pragma: no cover
|
|
# for any other unexpected errors, we log the error
|
|
# and keep going
|
|
self.logger.exception('post request handler error')
|
|
r = self._ok(jsonp_index=jsonp_index)
|
|
elif method == 'OPTIONS':
|
|
r = self._ok()
|
|
else:
|
|
self.logger.warning('Method %s not supported', method)
|
|
r = self._method_not_found()
|
|
if not isinstance(r, dict):
|
|
return r
|
|
if self.http_compression and \
|
|
len(r['response']) >= self.compression_threshold:
|
|
encodings = [e.split(';')[0].strip() for e in
|
|
environ.get('HTTP_ACCEPT_ENCODING', '').split(',')]
|
|
for encoding in encodings:
|
|
if encoding in self.compression_methods:
|
|
r['response'] = \
|
|
getattr(self, '_' + encoding)(r['response'])
|
|
r['headers'] += [('Content-Encoding', encoding)]
|
|
break
|
|
return await self._make_response(r, environ)
|
|
|
|
def start_background_task(self, target, *args, **kwargs):
|
|
"""Start a background task using the appropriate async model.
|
|
|
|
This is a utility function that applications can use to start a
|
|
background task using the method that is compatible with the
|
|
selected async mode.
|
|
|
|
:param target: the target function to execute.
|
|
:param args: arguments to pass to the function.
|
|
:param kwargs: keyword arguments to pass to the function.
|
|
|
|
The return value is a ``asyncio.Task`` object.
|
|
"""
|
|
return asyncio.ensure_future(target(*args, **kwargs))
|
|
|
|
async def sleep(self, seconds=0):
|
|
"""Sleep for the requested amount of time using the appropriate async
|
|
model.
|
|
|
|
This is a utility function that applications can use to put a task to
|
|
sleep without having to worry about using the correct call for the
|
|
selected async mode.
|
|
|
|
Note: this method is a coroutine.
|
|
"""
|
|
return await asyncio.sleep(seconds)
|
|
|
|
def create_queue(self, *args, **kwargs):
|
|
"""Create a queue object using the appropriate async model.
|
|
|
|
This is a utility function that applications can use to create a queue
|
|
without having to worry about using the correct call for the selected
|
|
async mode. For asyncio based async modes, this returns an instance of
|
|
``asyncio.Queue``.
|
|
"""
|
|
return asyncio.Queue(*args, **kwargs)
|
|
|
|
def get_queue_empty_exception(self):
|
|
"""Return the queue empty exception for the appropriate async model.
|
|
|
|
This is a utility function that applications can use to work with a
|
|
queue without having to worry about using the correct call for the
|
|
selected async mode. For asyncio based async modes, this returns an
|
|
instance of ``asyncio.QueueEmpty``.
|
|
"""
|
|
return asyncio.QueueEmpty
|
|
|
|
def create_event(self, *args, **kwargs):
|
|
"""Create an event object using the appropriate async model.
|
|
|
|
This is a utility function that applications can use to create an
|
|
event without having to worry about using the correct call for the
|
|
selected async mode. For asyncio based async modes, this returns
|
|
an instance of ``asyncio.Event``.
|
|
"""
|
|
return asyncio.Event(*args, **kwargs)
|
|
|
|
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')
|