bazarr/libs/socketio/client.py

524 lines
24 KiB
Python

import random
import engineio
from . import base_client
from . import exceptions
from . import packet
class Client(base_client.BaseClient):
"""A Socket.IO client.
This class implements a fully compliant Socket.IO web client with support
for websocket and long-polling transports.
:param reconnection: ``True`` if the client should automatically attempt to
reconnect to the server after an interruption, or
``False`` to not reconnect. The default is ``True``.
:param reconnection_attempts: How many reconnection attempts to issue
before giving up, or 0 for infinite attempts.
The default is 0.
:param reconnection_delay: How long to wait in seconds before the first
reconnection attempt. Each successive attempt
doubles this delay.
:param reconnection_delay_max: The maximum delay between reconnection
attempts.
:param randomization_factor: Randomization amount for each delay between
reconnection attempts. The default is 0.5,
which means that each delay is randomly
adjusted by +/- 50%.
:param logger: To enable logging set to ``True`` or pass a logger object to
use. To disable logging set to ``False``. The default is
``False``. Note that fatal errors are logged even when
``logger`` is ``False``.
:param serializer: The serialization method to use when transmitting
packets. Valid values are ``'default'``, ``'pickle'``,
``'msgpack'`` and ``'cbor'``. Alternatively, a subclass
of the :class:`Packet` class with custom implementations
of the ``encode()`` and ``decode()`` methods can be
provided. Client and server must use compatible
serializers.
: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 handle_sigint: Set to ``True`` to automatically handle disconnection
when the process is interrupted, or to ``False`` to
leave interrupt handling to the calling application.
Interrupt handling can only be enabled when the
client instance is created in the main thread.
The Engine.IO configuration supports the following settings:
:param request_timeout: A timeout in seconds for requests. The default is
5 seconds.
:param http_session: an initialized ``requests.Session`` object to be used
when sending requests to the server. Use it if you
need to add special client options such as proxy
servers, SSL certificates, etc.
:param ssl_verify: ``True`` to verify SSL certificates, or ``False`` to
skip SSL certificate verification, allowing
connections to servers with self signed certificates.
The default is ``True``.
:param engineio_logger: To enable Engine.IO logging set to ``True`` or pass
a logger object to use. To disable logging set to
``False``. The default is ``False``. Note that
fatal errors are logged even when
``engineio_logger`` is ``False``.
"""
def connect(self, url, headers={}, auth=None, transports=None,
namespaces=None, socketio_path='socket.io', wait=True,
wait_timeout=1, retry=False):
"""Connect to a Socket.IO server.
:param url: The URL of the Socket.IO server. It can include custom
query string parameters if required by the server. If a
function is provided, the client will invoke it to obtain
the URL each time a connection or reconnection is
attempted.
:param headers: A dictionary with custom headers to send with the
connection request. If a function is provided, the
client will invoke it to obtain the headers dictionary
each time a connection or reconnection is attempted.
:param auth: Authentication data passed to the server with the
connection request, normally a dictionary with one or
more string key/value pairs. If a function is provided,
the client will invoke it to obtain the authentication
data each time a connection or reconnection is attempted.
:param transports: The list of allowed transports. Valid transports
are ``'polling'`` and ``'websocket'``. If not
given, the polling transport is connected first,
then an upgrade to websocket is attempted.
:param namespaces: The namespaces to connect as a string or list of
strings. If not given, the namespaces that have
registered event handlers are connected.
:param socketio_path: The endpoint where the Socket.IO server is
installed. The default value is appropriate for
most cases.
:param wait: if set to ``True`` (the default) the call only returns
when all the namespaces are connected. If set to
``False``, the call returns as soon as the Engine.IO
transport is connected, and the namespaces will connect
in the background.
:param wait_timeout: How long the client should wait for the
connection. The default is 1 second. This
argument is only considered when ``wait`` is set
to ``True``.
:param retry: Apply the reconnection logic if the initial connection
attempt fails. The default is ``False``.
Example usage::
sio = socketio.Client()
sio.connect('http://localhost:5000')
"""
if self.connected:
raise exceptions.ConnectionError('Already connected')
self.connection_url = url
self.connection_headers = headers
self.connection_auth = auth
self.connection_transports = transports
self.connection_namespaces = namespaces
self.socketio_path = socketio_path
if namespaces is None:
namespaces = list(set(self.handlers.keys()).union(
set(self.namespace_handlers.keys())))
if len(namespaces) == 0:
namespaces = ['/']
elif isinstance(namespaces, str):
namespaces = [namespaces]
self.connection_namespaces = namespaces
self.namespaces = {}
if self._connect_event is None:
self._connect_event = self.eio.create_event()
else:
self._connect_event.clear()
real_url = self._get_real_value(self.connection_url)
real_headers = self._get_real_value(self.connection_headers)
try:
self.eio.connect(real_url, headers=real_headers,
transports=transports,
engineio_path=socketio_path)
except engineio.exceptions.ConnectionError as exc:
for n in self.connection_namespaces:
self._trigger_event(
'connect_error', n,
exc.args[1] if len(exc.args) > 1 else exc.args[0])
if retry: # pragma: no cover
self._handle_reconnect()
if self.eio.state == 'connected':
return
raise exceptions.ConnectionError(exc.args[0]) from None
if wait:
while self._connect_event.wait(timeout=wait_timeout):
self._connect_event.clear()
if set(self.namespaces) == set(self.connection_namespaces):
break
if set(self.namespaces) != set(self.connection_namespaces):
self.disconnect()
raise exceptions.ConnectionError(
'One or more namespaces failed to connect')
self.connected = True
def wait(self):
"""Wait until the connection with the server ends.
Client applications can use this function to block the main thread
during the life of the connection.
"""
while True:
self.eio.wait()
self.sleep(1) # give the reconnect task time to start up
if not self._reconnect_task:
break
self._reconnect_task.join()
if self.eio.state != 'connected':
break
def emit(self, event, data=None, namespace=None, callback=None):
"""Emit a custom event to the server.
:param event: The event name. It can be any string. The event names
``'connect'``, ``'message'`` and ``'disconnect'`` are
reserved and should not be used.
:param data: The data to send to the server. Data can be of
type ``str``, ``bytes``, ``list`` or ``dict``. To send
multiple arguments, use a tuple where each element is of
one of the types indicated above.
:param namespace: The Socket.IO namespace for the event. If this
argument is omitted the event is emitted to the
default namespace.
:param callback: If given, this function will be called to acknowledge
the server has received the message. The arguments
that will be passed to the function are those provided
by the server.
Note: this method is not thread safe. If multiple threads are emitting
at the same time on the same client connection, messages composed of
multiple packets may end up being sent in an incorrect sequence. Use
standard concurrency solutions (such as a Lock object) to prevent this
situation.
"""
namespace = namespace or '/'
if namespace not in self.namespaces:
raise exceptions.BadNamespaceError(
namespace + ' is not a connected namespace.')
self.logger.info('Emitting event "%s" [%s]', event, namespace)
if callback is not None:
id = self._generate_ack_id(namespace, callback)
else:
id = None
# tuples are expanded to multiple arguments, everything else is sent
# as a single argument
if isinstance(data, tuple):
data = list(data)
elif data is not None:
data = [data]
else:
data = []
self._send_packet(self.packet_class(packet.EVENT, namespace=namespace,
data=[event] + data, id=id))
def send(self, data, namespace=None, callback=None):
"""Send a message to the server.
This function emits an event with the name ``'message'``. Use
:func:`emit` to issue custom event names.
:param data: The data to send to the server. Data can be of
type ``str``, ``bytes``, ``list`` or ``dict``. To send
multiple arguments, use a tuple where each element is of
one of the types indicated above.
:param namespace: The Socket.IO namespace for the event. If this
argument is omitted the event is emitted to the
default namespace.
:param callback: If given, this function will be called to acknowledge
the server has received the message. The arguments
that will be passed to the function are those provided
by the server.
"""
self.emit('message', data=data, namespace=namespace,
callback=callback)
def call(self, event, data=None, namespace=None, timeout=60):
"""Emit a custom event to the server and wait for the response.
This method issues an emit with a callback and waits for the callback
to be invoked before returning. If the callback isn't invoked before
the timeout, then a ``TimeoutError`` exception is raised. If the
Socket.IO connection drops during the wait, this method still waits
until the specified timeout.
:param event: The event name. It can be any string. The event names
``'connect'``, ``'message'`` and ``'disconnect'`` are
reserved and should not be used.
:param data: The data to send to the server. Data can be of
type ``str``, ``bytes``, ``list`` or ``dict``. To send
multiple arguments, use a tuple where each element is of
one of the types indicated above.
:param namespace: The Socket.IO namespace for the event. If this
argument is omitted the event is emitted to the
default namespace.
:param timeout: The waiting timeout. If the timeout is reached before
the server acknowledges the event, then a
``TimeoutError`` exception is raised.
Note: this method is not thread safe. If multiple threads are emitting
at the same time on the same client connection, messages composed of
multiple packets may end up being sent in an incorrect sequence. Use
standard concurrency solutions (such as a Lock object) to prevent this
situation.
"""
callback_event = self.eio.create_event()
callback_args = []
def event_callback(*args):
callback_args.append(args)
callback_event.set()
self.emit(event, data=data, namespace=namespace,
callback=event_callback)
if not callback_event.wait(timeout=timeout):
raise exceptions.TimeoutError()
return callback_args[0] if len(callback_args[0]) > 1 \
else callback_args[0][0] if len(callback_args[0]) == 1 \
else None
def disconnect(self):
"""Disconnect from the server."""
# here we just request the disconnection
# later in _handle_eio_disconnect we invoke the disconnect handler
for n in self.namespaces:
self._send_packet(self.packet_class(
packet.DISCONNECT, namespace=n))
self.eio.disconnect(abort=True)
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.
This function returns an object that represents the background task,
on which the ``join()`` methond can be invoked to wait for the task to
complete.
"""
return self.eio.start_background_task(target, *args, **kwargs)
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.
"""
return self.eio.sleep(seconds)
def _get_real_value(self, value):
"""Return the actual value, for parameters that can also be given as
callables."""
if not callable(value):
return value
return value()
def _send_packet(self, pkt):
"""Send a Socket.IO packet to the server."""
encoded_packet = pkt.encode()
if isinstance(encoded_packet, list):
for ep in encoded_packet:
self.eio.send(ep)
else:
self.eio.send(encoded_packet)
def _handle_connect(self, namespace, data):
namespace = namespace or '/'
if namespace not in self.namespaces:
self.logger.info('Namespace {} is connected'.format(namespace))
self.namespaces[namespace] = (data or {}).get('sid', self.sid)
self._trigger_event('connect', namespace=namespace)
self._connect_event.set()
def _handle_disconnect(self, namespace):
if not self.connected:
return
namespace = namespace or '/'
self._trigger_event('disconnect', namespace=namespace)
self._trigger_event('__disconnect_final', namespace=namespace)
if namespace in self.namespaces:
del self.namespaces[namespace]
if not self.namespaces:
self.connected = False
self.eio.disconnect(abort=True)
def _handle_event(self, namespace, id, data):
namespace = namespace or '/'
self.logger.info('Received event "%s" [%s]', data[0], namespace)
r = self._trigger_event(data[0], namespace, *data[1:])
if id is not None:
# send ACK packet with the response returned by the handler
# tuples are expanded as multiple arguments
if r is None:
data = []
elif isinstance(r, tuple):
data = list(r)
else:
data = [r]
self._send_packet(self.packet_class(
packet.ACK, namespace=namespace, id=id, data=data))
def _handle_ack(self, namespace, id, data):
namespace = namespace or '/'
self.logger.info('Received ack [%s]', namespace)
callback = None
try:
callback = self.callbacks[namespace][id]
except KeyError:
# if we get an unknown callback we just ignore it
self.logger.warning('Unknown callback received, ignoring.')
else:
del self.callbacks[namespace][id]
if callback is not None:
callback(*data)
def _handle_error(self, namespace, data):
namespace = namespace or '/'
self.logger.info('Connection to namespace {} was rejected'.format(
namespace))
if data is None:
data = tuple()
elif not isinstance(data, (tuple, list)):
data = (data,)
self._trigger_event('connect_error', namespace, *data)
self._connect_event.set()
if namespace in self.namespaces:
del self.namespaces[namespace]
if namespace == '/':
self.namespaces = {}
self.connected = False
def _trigger_event(self, event, namespace, *args):
"""Invoke an application event handler."""
# first see if we have an explicit handler for the event
handler, args = self._get_event_handler(event, namespace, args)
if handler:
return handler(*args)
# or else, forward the event to a namespace handler if one exists
handler, args = self._get_namespace_handler(namespace, args)
if handler:
return handler.trigger_event(event, *args)
def _handle_reconnect(self):
if self._reconnect_abort is None: # pragma: no cover
self._reconnect_abort = self.eio.create_event()
self._reconnect_abort.clear()
base_client.reconnecting_clients.append(self)
attempt_count = 0
current_delay = self.reconnection_delay
while True:
delay = current_delay
current_delay *= 2
if delay > self.reconnection_delay_max:
delay = self.reconnection_delay_max
delay += self.randomization_factor * (2 * random.random() - 1)
self.logger.info(
'Connection failed, new attempt in {:.02f} seconds'.format(
delay))
if self._reconnect_abort.wait(delay):
self.logger.info('Reconnect task aborted')
for n in self.connection_namespaces:
self._trigger_event('__disconnect_final', namespace=n)
break
attempt_count += 1
try:
self.connect(self.connection_url,
headers=self.connection_headers,
auth=self.connection_auth,
transports=self.connection_transports,
namespaces=self.connection_namespaces,
socketio_path=self.socketio_path,
retry=False)
except (exceptions.ConnectionError, ValueError):
pass
else:
self.logger.info('Reconnection successful')
self._reconnect_task = None
break
if self.reconnection_attempts and \
attempt_count >= self.reconnection_attempts:
self.logger.info(
'Maximum reconnection attempts reached, giving up')
for n in self.connection_namespaces:
self._trigger_event('__disconnect_final', namespace=n)
break
base_client.reconnecting_clients.remove(self)
def _handle_eio_connect(self):
"""Handle the Engine.IO connection event."""
self.logger.info('Engine.IO connection established')
self.sid = self.eio.sid
real_auth = self._get_real_value(self.connection_auth) or {}
for n in self.connection_namespaces:
self._send_packet(self.packet_class(
packet.CONNECT, data=real_auth, namespace=n))
def _handle_eio_message(self, data):
"""Dispatch Engine.IO messages."""
if self._binary_packet:
pkt = self._binary_packet
if pkt.add_attachment(data):
self._binary_packet = None
if pkt.packet_type == packet.BINARY_EVENT:
self._handle_event(pkt.namespace, pkt.id, pkt.data)
else:
self._handle_ack(pkt.namespace, pkt.id, pkt.data)
else:
pkt = self.packet_class(encoded_packet=data)
if pkt.packet_type == packet.CONNECT:
self._handle_connect(pkt.namespace, pkt.data)
elif pkt.packet_type == packet.DISCONNECT:
self._handle_disconnect(pkt.namespace)
elif pkt.packet_type == packet.EVENT:
self._handle_event(pkt.namespace, pkt.id, pkt.data)
elif pkt.packet_type == packet.ACK:
self._handle_ack(pkt.namespace, pkt.id, pkt.data)
elif pkt.packet_type == packet.BINARY_EVENT or \
pkt.packet_type == packet.BINARY_ACK:
self._binary_packet = pkt
elif pkt.packet_type == packet.CONNECT_ERROR:
self._handle_error(pkt.namespace, pkt.data)
else:
raise ValueError('Unknown packet type.')
def _handle_eio_disconnect(self):
"""Handle the Engine.IO disconnection event."""
self.logger.info('Engine.IO connection dropped')
will_reconnect = self.reconnection and self.eio.state == 'connected'
if self.connected:
for n in self.namespaces:
self._trigger_event('disconnect', namespace=n)
if not will_reconnect:
self._trigger_event('__disconnect_final', namespace=n)
self.namespaces = {}
self.connected = False
self.callbacks = {}
self._binary_packet = None
self.sid = None
if will_reconnect:
self._reconnect_task = self.start_background_task(
self._handle_reconnect)
def _engineio_client_class(self):
return engineio.Client