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606 lines
26 KiB
606 lines
26 KiB
from base64 import b64encode
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from engineio.json import JSONDecodeError
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import logging
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import queue
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import ssl
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import threading
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import time
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import urllib
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try:
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import requests
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except ImportError: # pragma: no cover
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requests = None
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try:
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import websocket
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except ImportError: # pragma: no cover
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websocket = None
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from . import base_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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default_logger = logging.getLogger('engineio.client')
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class Client(base_client.BaseClient):
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"""An Engine.IO client.
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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.
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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 ``requests.Session`` object to be used
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when sending requests to the server. Use it if you
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need to add special client options such as proxy
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servers, SSL certificates, custom CA bundle, 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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:param handle_sigint: Set to ``True`` to automatically handle disconnection
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when the process is interrupted, or to ``False`` to
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leave interrupt handling to the calling application.
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Interrupt handling can only be enabled when the
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client instance is created in the main thread.
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:param websocket_extra_options: Dictionary containing additional keyword
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arguments passed to
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``websocket.create_connection()``.
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"""
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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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Example usage::
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eio = engineio.Client()
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eio.connect('http://localhost:5000')
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"""
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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 getattr(self, '_connect_' + self.transports[0])(
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url, headers or {}, engineio_path)
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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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"""
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if self.read_loop_task:
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self.read_loop_task.join()
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def send(self, data):
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"""Send a message to the server.
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:param data: The data to send to the server. 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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"""
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self._send_packet(packet.Packet(packet.MESSAGE, data=data))
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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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"""
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if self.state == 'connected':
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self._send_packet(packet.Packet(packet.CLOSE))
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self.queue.put(None)
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self.state = 'disconnecting'
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self._trigger_event('disconnect', run_async=False)
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if self.current_transport == 'websocket':
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self.ws.close()
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if not abort:
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self.read_loop_task.join()
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self.state = 'disconnected'
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try:
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base_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 that represents the background task,
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on which the ``join()`` method can be invoked to wait for the task to
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complete.
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"""
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th = threading.Thread(target=target, args=args, kwargs=kwargs,
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daemon=True)
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th.start()
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return th
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def sleep(self, seconds=0):
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"""Sleep for the requested amount of time."""
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return time.sleep(seconds)
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def create_queue(self, *args, **kwargs):
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"""Create a queue object."""
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q = queue.Queue(*args, **kwargs)
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q.Empty = queue.Empty
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return q
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def create_event(self, *args, **kwargs):
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"""Create an event object."""
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return threading.Event(*args, **kwargs)
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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 requests is None: # pragma: no cover
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# not installed
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self.logger.error('requests package is not installed -- cannot '
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'send HTTP 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 = 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 or isinstance(r, str):
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self._reset()
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raise exceptions.ConnectionError(
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r or 'Connection refused by the server')
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if r.status_code < 200 or r.status_code >= 300:
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self._reset()
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try:
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arg = r.json()
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except JSONDecodeError:
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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_code), arg)
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try:
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p = payload.Payload(encoded_payload=r.content.decode('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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base_client.connected_clients.append(self)
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self._trigger_event('connect', run_async=False)
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for pkt in p.packets[1:]:
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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 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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# start background tasks associated with this client
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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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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 websocket is None: # pragma: no cover
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# not installed
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self.logger.error('websocket-client package not installed, only '
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'polling transport is available')
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return False
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websocket_url = self._get_engineio_url(url, engineio_path, '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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# get cookies and other settings from the long-polling connection
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# so that they are preserved when connecting to the WebSocket route
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cookies = None
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extra_options = {}
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if self.http:
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# cookies
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cookies = '; '.join(["{}={}".format(cookie.name, cookie.value)
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for cookie in self.http.cookies])
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for header, value in headers.items():
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if header.lower() == 'cookie':
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if cookies:
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cookies += '; '
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cookies += value
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del headers[header]
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break
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# auth
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if 'Authorization' not in headers and self.http.auth is not None:
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if not isinstance(self.http.auth, tuple): # pragma: no cover
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raise ValueError('Only basic authentication is supported')
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basic_auth = '{}:{}'.format(
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self.http.auth[0], self.http.auth[1]).encode('utf-8')
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basic_auth = b64encode(basic_auth).decode('utf-8')
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headers['Authorization'] = 'Basic ' + basic_auth
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# cert
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# this can be given as ('certfile', 'keyfile') or just 'certfile'
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if isinstance(self.http.cert, tuple):
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extra_options['sslopt'] = {
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'certfile': self.http.cert[0],
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'keyfile': self.http.cert[1]}
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elif self.http.cert:
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extra_options['sslopt'] = {'certfile': self.http.cert}
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# proxies
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if self.http.proxies:
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proxy_url = None
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if websocket_url.startswith('ws://'):
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proxy_url = self.http.proxies.get(
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'ws', self.http.proxies.get('http'))
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else: # wss://
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proxy_url = self.http.proxies.get(
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'wss', self.http.proxies.get('https'))
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if proxy_url:
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parsed_url = urllib.parse.urlparse(
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proxy_url if '://' in proxy_url
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else 'scheme://' + proxy_url)
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extra_options['http_proxy_host'] = parsed_url.hostname
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extra_options['http_proxy_port'] = parsed_url.port
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extra_options['http_proxy_auth'] = (
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(parsed_url.username, parsed_url.password)
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if parsed_url.username or parsed_url.password
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else None)
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# verify
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if isinstance(self.http.verify, str):
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if 'sslopt' in extra_options:
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extra_options['sslopt']['ca_certs'] = self.http.verify
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else:
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extra_options['sslopt'] = {'ca_certs': self.http.verify}
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elif not self.http.verify:
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self.ssl_verify = False
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if not self.ssl_verify:
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if 'sslopt' in extra_options:
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extra_options['sslopt'].update({"cert_reqs": ssl.CERT_NONE})
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else:
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extra_options['sslopt'] = {"cert_reqs": ssl.CERT_NONE}
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# combine internally generated options with the ones supplied by the
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# caller. The caller's options take precedence.
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headers.update(self.websocket_extra_options.pop('header', {}))
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extra_options['header'] = headers
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extra_options['cookie'] = cookies
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extra_options['enable_multithread'] = True
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extra_options['timeout'] = self.request_timeout
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extra_options.update(self.websocket_extra_options)
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try:
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ws = websocket.create_connection(
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websocket_url + self._get_url_timestamp(), **extra_options)
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except (ConnectionError, IOError, websocket.WebSocketException):
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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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ws.send(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 = ws.recv()
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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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ws.send(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 = ws.recv()
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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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base_client.connected_clients.append(self)
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self._trigger_event('connect', run_async=False)
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self.ws = ws
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self.ws.settimeout(self.ping_interval + self.ping_timeout)
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# start background tasks associated with this client
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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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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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self._trigger_event('message', pkt.data, run_async=True)
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elif pkt.packet_type == packet.PING:
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self._send_packet(packet.Packet(packet.PONG, pkt.data))
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elif pkt.packet_type == packet.CLOSE:
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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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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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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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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:
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self.http = requests.Session()
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if not self.ssl_verify:
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self.http.verify = False
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try:
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return self.http.request(method, url, headers=headers, data=body,
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timeout=timeout)
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except requests.exceptions.RequestException 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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return str(exc)
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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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if event in self.handlers:
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if run_async:
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return self.start_background_task(self.handlers[event], *args)
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else:
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try:
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return self.handlers[event](*args)
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except:
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self.logger.exception(event + ' handler error')
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|
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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' and self.write_loop_task:
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self.logger.info(
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'Sending polling GET request to ' + self.base_url)
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r = 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 or isinstance(r, str):
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self.logger.warning(
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r or 'Connection refused by the server, aborting')
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self.queue.put(None)
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break
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if r.status_code < 200 or r.status_code >= 300:
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self.logger.warning('Unexpected status code %s in server '
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'response, aborting', r.status_code)
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self.queue.put(None)
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break
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try:
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p = payload.Payload(encoded_payload=r.content.decode('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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self.queue.put(None)
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break
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for pkt in p.packets:
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self._receive_packet(pkt)
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|
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if self.write_loop_task: # pragma: no branch
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self.logger.info('Waiting for write loop task to end')
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self.write_loop_task.join()
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if self.state == 'connected':
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self._trigger_event('disconnect', run_async=False)
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try:
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base_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()
|
|
self.logger.info('Exiting read loop task')
|
|
|
|
def _read_loop_websocket(self):
|
|
"""Read packets from the Engine.IO WebSocket connection."""
|
|
while self.state == 'connected':
|
|
p = None
|
|
try:
|
|
p = self.ws.recv()
|
|
if len(p) == 0: # pragma: no cover
|
|
# websocket client can return an empty string after close
|
|
raise websocket.WebSocketConnectionClosedException()
|
|
except websocket.WebSocketTimeoutException:
|
|
self.logger.warning(
|
|
'Server has stopped communicating, aborting')
|
|
self.queue.put(None)
|
|
break
|
|
except websocket.WebSocketConnectionClosedException:
|
|
self.logger.warning(
|
|
'WebSocket connection was closed, aborting')
|
|
self.queue.put(None)
|
|
break
|
|
except Exception as e: # pragma: no cover
|
|
if type(e) is OSError and e.errno == 9:
|
|
self.logger.info(
|
|
'WebSocket connection is closing, aborting',
|
|
str(e))
|
|
else:
|
|
self.logger.info(
|
|
'Unexpected error receiving packet: "%s", aborting',
|
|
str(e))
|
|
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))
|
|
self.queue.put(None)
|
|
break
|
|
self._receive_packet(pkt)
|
|
|
|
if self.write_loop_task: # pragma: no branch
|
|
self.logger.info('Waiting for write loop task to end')
|
|
self.write_loop_task.join()
|
|
if self.state == 'connected':
|
|
self._trigger_event('disconnect', run_async=False)
|
|
try:
|
|
base_client.connected_clients.remove(self)
|
|
except ValueError: # pragma: no cover
|
|
pass
|
|
self._reset()
|
|
self.logger.info('Exiting read loop task')
|
|
|
|
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 = [self.queue.get(timeout=timeout)]
|
|
except self.queue.Empty:
|
|
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(block=False))
|
|
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 = self._send_request(
|
|
'POST', self.base_url, body=p.encode(),
|
|
headers={'Content-Type': 'text/plain'},
|
|
timeout=self.request_timeout)
|
|
for pkt in packets:
|
|
self.queue.task_done()
|
|
if r is None or isinstance(r, str):
|
|
self.logger.warning(
|
|
r or 'Connection refused by the server, aborting')
|
|
break
|
|
if r.status_code < 200 or r.status_code >= 300:
|
|
self.logger.warning('Unexpected status code %s in server '
|
|
'response, aborting', r.status_code)
|
|
self.write_loop_task = None
|
|
break
|
|
else:
|
|
# websocket
|
|
try:
|
|
for pkt in packets:
|
|
encoded_packet = pkt.encode()
|
|
if pkt.binary:
|
|
self.ws.send_binary(encoded_packet)
|
|
else:
|
|
self.ws.send(encoded_packet)
|
|
self.queue.task_done()
|
|
except (websocket.WebSocketConnectionClosedException,
|
|
BrokenPipeError, OSError):
|
|
self.logger.warning(
|
|
'WebSocket connection was closed, aborting')
|
|
break
|
|
self.logger.info('Exiting write loop task')
|