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bazarr/libs/engineio/asyncio_server.py

515 lines
22 KiB

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import asyncio
import urllib
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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
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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.
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:param max_http_buffer_size: The maximum size of a message when using the
polling transport. The default is 1,000,000
bytes.
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: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.
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: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``.
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: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 transports: The list of allowed transports. Valid transports
are ``'polling'`` and ``'websocket'``. Defaults to
``['polling', 'websocket']``.
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: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):
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"""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))
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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([asyncio.create_task(client.close())
for client in self.sockets.values()])
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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)
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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 uses an allowed transport
transport = query.get('transport', ['polling'])[0]
if transport not in self.transports:
self._log_error_once('Invalid transport', 'bad-transport')
return await self._make_response(
self._bad_request('Invalid transport'), environ)
# 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)
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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')
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elif method == 'GET':
if sid is None:
# 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':
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r = await self._handle_connect(environ, transport,
jsonp_index)
else:
self._log_error_once('Invalid websocket upgrade',
'bad-upgrade')
r = self._bad_request('Invalid websocket upgrade')
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else:
if sid not in self.sockets:
self._log_error_once('Invalid session ' + sid, 'bad-sid')
r = self._bad_request('Invalid session ' + sid)
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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)
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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)
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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)
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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):
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"""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()
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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()
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ret = await self._trigger_event('connect', sid, environ,
run_async=False)
if ret is not None and ret is not True:
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del self.sockets[sid]
self.logger.warning('Application rejected connection')
return self._unauthorized(ret or None)
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if transport == 'websocket':
ret = await s.handle_get_request(environ)
if s.closed and sid in self.sockets:
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# 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'
})
)]
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try:
return self._ok(await s.poll(), headers=headers,
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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,
):
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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')