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479 lines
22 KiB
479 lines
22 KiB
import selectors
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import socket
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import ssl
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from time import time
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from urllib.parse import urlsplit
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from wsproto import ConnectionType, WSConnection
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from wsproto.events import (
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AcceptConnection,
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RejectConnection,
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CloseConnection,
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Message,
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Request,
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Ping,
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Pong,
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TextMessage,
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BytesMessage,
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)
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from wsproto.extensions import PerMessageDeflate
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from wsproto.frame_protocol import CloseReason
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from wsproto.utilities import LocalProtocolError
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from .errors import ConnectionError, ConnectionClosed
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class Base:
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def __init__(self, sock=None, connection_type=None, receive_bytes=4096,
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ping_interval=None, max_message_size=None,
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thread_class=None, event_class=None, selector_class=None):
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#: The name of the subprotocol chosen for the WebSocket connection.
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self.subprotocol = None
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self.sock = sock
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self.receive_bytes = receive_bytes
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self.ping_interval = ping_interval
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self.max_message_size = max_message_size
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self.pong_received = True
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self.input_buffer = []
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self.incoming_message = None
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self.incoming_message_len = 0
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self.connected = False
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self.is_server = (connection_type == ConnectionType.SERVER)
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self.close_reason = CloseReason.NO_STATUS_RCVD
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self.close_message = None
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if thread_class is None:
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import threading
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thread_class = threading.Thread
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if event_class is None: # pragma: no branch
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import threading
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event_class = threading.Event
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if selector_class is None:
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selector_class = selectors.DefaultSelector
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self.selector_class = selector_class
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self.event = event_class()
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self.ws = WSConnection(connection_type)
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self.handshake()
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if not self.connected: # pragma: no cover
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raise ConnectionError()
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self.thread = thread_class(target=self._thread)
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self.thread.name = self.thread.name.replace(
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'(_thread)', '(simple_websocket.Base._thread)')
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self.thread.start()
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def handshake(self): # pragma: no cover
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# to be implemented by subclasses
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pass
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def send(self, data):
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"""Send data over the WebSocket connection.
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:param data: The data to send. If ``data`` is of type ``bytes``, then
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a binary message is sent. Else, the message is sent in
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text format.
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"""
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if not self.connected:
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raise ConnectionClosed(self.close_reason, self.close_message)
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if isinstance(data, bytes):
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out_data = self.ws.send(Message(data=data))
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else:
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out_data = self.ws.send(TextMessage(data=str(data)))
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self.sock.send(out_data)
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def receive(self, timeout=None):
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"""Receive data over the WebSocket connection.
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:param timeout: Amount of time to wait for the data, in seconds. Set
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to ``None`` (the default) to wait indefinitely. Set
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to 0 to read without blocking.
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The data received is returned, as ``bytes`` or ``str``, depending on
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the type of the incoming message.
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"""
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while self.connected and not self.input_buffer:
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if not self.event.wait(timeout=timeout):
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return None
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self.event.clear()
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try:
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return self.input_buffer.pop(0)
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except IndexError:
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pass
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if not self.connected: # pragma: no cover
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raise ConnectionClosed(self.close_reason, self.close_message)
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def close(self, reason=None, message=None):
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"""Close the WebSocket connection.
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:param reason: A numeric status code indicating the reason of the
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closure, as defined by the WebSocket specification. The
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default is 1000 (normal closure).
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:param message: A text message to be sent to the other side.
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"""
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if not self.connected:
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raise ConnectionClosed(self.close_reason, self.close_message)
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out_data = self.ws.send(CloseConnection(
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reason or CloseReason.NORMAL_CLOSURE, message))
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try:
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self.sock.send(out_data)
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except BrokenPipeError: # pragma: no cover
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pass
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self.connected = False
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def choose_subprotocol(self, request): # pragma: no cover
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# The method should return the subprotocol to use, or ``None`` if no
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# subprotocol is chosen. Can be overridden by subclasses that implement
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# the server-side of the WebSocket protocol.
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return None
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def _thread(self):
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sel = None
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if self.ping_interval:
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next_ping = time() + self.ping_interval
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sel = self.selector_class()
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sel.register(self.sock, selectors.EVENT_READ, True)
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while self.connected:
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try:
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if sel:
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now = time()
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if next_ping <= now or not sel.select(next_ping - now):
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# we reached the timeout, we have to send a ping
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if not self.pong_received:
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self.close(reason=CloseReason.POLICY_VIOLATION,
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message='Ping/Pong timeout')
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break
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self.pong_received = False
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self.sock.send(self.ws.send(Ping()))
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next_ping = max(now, next_ping) + self.ping_interval
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continue
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in_data = self.sock.recv(self.receive_bytes)
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if len(in_data) == 0:
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raise OSError()
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self.ws.receive_data(in_data)
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self.connected = self._handle_events()
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except (OSError, ConnectionResetError): # pragma: no cover
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self.connected = False
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self.event.set()
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break
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sel.close() if sel else None
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self.sock.close()
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def _handle_events(self):
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keep_going = True
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out_data = b''
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for event in self.ws.events():
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try:
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if isinstance(event, Request):
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self.subprotocol = self.choose_subprotocol(event)
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out_data += self.ws.send(AcceptConnection(
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subprotocol=self.subprotocol,
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extensions=[PerMessageDeflate()]))
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elif isinstance(event, CloseConnection):
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if self.is_server:
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out_data += self.ws.send(event.response())
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self.close_reason = event.code
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self.close_message = event.reason
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self.connected = False
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self.event.set()
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keep_going = False
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elif isinstance(event, Ping):
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out_data += self.ws.send(event.response())
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elif isinstance(event, Pong):
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self.pong_received = True
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elif isinstance(event, (TextMessage, BytesMessage)):
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self.incoming_message_len += len(event.data)
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if self.max_message_size and \
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self.incoming_message_len > self.max_message_size:
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out_data += self.ws.send(CloseConnection(
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CloseReason.MESSAGE_TOO_BIG, 'Message is too big'))
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self.event.set()
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keep_going = False
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break
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if self.incoming_message is None:
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# store message as is first
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# if it is the first of a group, the message will be
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# converted to bytearray on arrival of the second
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# part, since bytearrays are mutable and can be
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# concatenated more efficiently
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self.incoming_message = event.data
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elif isinstance(event, TextMessage):
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if not isinstance(self.incoming_message, bytearray):
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# convert to bytearray and append
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self.incoming_message = bytearray(
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(self.incoming_message + event.data).encode())
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else:
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# append to bytearray
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self.incoming_message += event.data.encode()
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else:
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if not isinstance(self.incoming_message, bytearray):
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# convert to mutable bytearray and append
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self.incoming_message = bytearray(
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self.incoming_message + event.data)
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else:
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# append to bytearray
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self.incoming_message += event.data
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if not event.message_finished:
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continue
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if isinstance(self.incoming_message, (str, bytes)):
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# single part message
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self.input_buffer.append(self.incoming_message)
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elif isinstance(event, TextMessage):
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# convert multi-part message back to text
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self.input_buffer.append(
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self.incoming_message.decode())
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else:
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# convert multi-part message back to bytes
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self.input_buffer.append(bytes(self.incoming_message))
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self.incoming_message = None
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self.incoming_message_len = 0
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self.event.set()
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else: # pragma: no cover
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pass
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except LocalProtocolError: # pragma: no cover
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out_data = b''
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self.event.set()
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keep_going = False
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if out_data:
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self.sock.send(out_data)
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return keep_going
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class Server(Base):
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"""This class implements a WebSocket server.
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Instead of creating an instance of this class directly, use the
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``accept()`` class method to create individual instances of the server,
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each bound to a client request.
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"""
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def __init__(self, environ, subprotocols=None, receive_bytes=4096,
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ping_interval=None, max_message_size=None, thread_class=None,
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event_class=None, selector_class=None):
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self.environ = environ
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self.subprotocols = subprotocols or []
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if isinstance(self.subprotocols, str):
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self.subprotocols = [self.subprotocols]
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self.mode = 'unknown'
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sock = None
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if 'werkzeug.socket' in environ:
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# extract socket from Werkzeug's WSGI environment
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sock = environ.get('werkzeug.socket')
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self.mode = 'werkzeug'
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elif 'gunicorn.socket' in environ:
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# extract socket from Gunicorn WSGI environment
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sock = environ.get('gunicorn.socket')
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self.mode = 'gunicorn'
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elif 'eventlet.input' in environ: # pragma: no cover
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# extract socket from Eventlet's WSGI environment
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sock = environ.get('eventlet.input').get_socket()
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self.mode = 'eventlet'
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elif environ.get('SERVER_SOFTWARE', '').startswith(
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'gevent'): # pragma: no cover
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# extract socket from Gevent's WSGI environment
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wsgi_input = environ['wsgi.input']
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if not hasattr(wsgi_input, 'raw') and hasattr(wsgi_input, 'rfile'):
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wsgi_input = wsgi_input.rfile
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if hasattr(wsgi_input, 'raw'):
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sock = wsgi_input.raw._sock
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try:
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sock = sock.dup()
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except NotImplementedError:
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pass
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self.mode = 'gevent'
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if sock is None:
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raise RuntimeError('Cannot obtain socket from WSGI environment.')
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super().__init__(sock, connection_type=ConnectionType.SERVER,
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receive_bytes=receive_bytes,
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ping_interval=ping_interval,
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max_message_size=max_message_size,
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thread_class=thread_class, event_class=event_class,
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selector_class=selector_class)
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@classmethod
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def accept(cls, environ, subprotocols=None, receive_bytes=4096,
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ping_interval=None, max_message_size=None, thread_class=None,
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event_class=None, selector_class=None):
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"""Accept a WebSocket connection from a client.
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:param environ: A WSGI ``environ`` dictionary with the request details.
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Among other things, this class expects to find the
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low-level network socket for the connection somewhere
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in this dictionary. Since the WSGI specification does
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not cover where or how to store this socket, each web
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server does this in its own different way. Werkzeug,
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Gunicorn, Eventlet and Gevent are the only web servers
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that are currently supported.
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:param subprotocols: A list of supported subprotocols, or ``None`` (the
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default) to disable subprotocol negotiation.
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:param receive_bytes: The size of the receive buffer, in bytes. The
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default is 4096.
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:param ping_interval: Send ping packets to clients at the requested
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interval in seconds. Set to ``None`` (the
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default) to disable ping/pong logic. Enable to
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prevent disconnections when the line is idle for
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a certain amount of time, or to detect
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unresponsive clients and disconnect them. A
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recommended interval is 25 seconds.
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:param max_message_size: The maximum size allowed for a message, in
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bytes, or ``None`` for no limit. The default
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is ``None``.
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:param thread_class: The ``Thread`` class to use when creating
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background threads. The default is the
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``threading.Thread`` class from the Python
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standard library.
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:param event_class: The ``Event`` class to use when creating event
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objects. The default is the `threading.Event``
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class from the Python standard library.
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:param selector_class: The ``Selector`` class to use when creating
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selectors. The default is the
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``selectors.DefaultSelector`` class from the
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Python standard library.
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"""
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return cls(environ, subprotocols=subprotocols,
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receive_bytes=receive_bytes, ping_interval=ping_interval,
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max_message_size=max_message_size,
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thread_class=thread_class, event_class=event_class,
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selector_class=selector_class)
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def handshake(self):
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in_data = b'GET / HTTP/1.1\r\n'
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for key, value in self.environ.items():
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if key.startswith('HTTP_'):
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header = '-'.join([p.capitalize() for p in key[5:].split('_')])
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in_data += f'{header}: {value}\r\n'.encode()
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in_data += b'\r\n'
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self.ws.receive_data(in_data)
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self.connected = self._handle_events()
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def choose_subprotocol(self, request):
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"""Choose a subprotocol to use for the WebSocket connection.
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The default implementation selects the first protocol requested by the
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client that is accepted by the server. Subclasses can override this
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method to implement a different subprotocol negotiation algorithm.
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:param request: A ``Request`` object.
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The method should return the subprotocol to use, or ``None`` if no
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subprotocol is chosen.
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"""
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for subprotocol in request.subprotocols:
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if subprotocol in self.subprotocols:
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return subprotocol
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return None
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class Client(Base):
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"""This class implements a WebSocket client.
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Instead of creating an instance of this class directly, use the
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``connect()`` class method to create an instance that is connected to a
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server.
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"""
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def __init__(self, url, subprotocols=None, headers=None,
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receive_bytes=4096, ping_interval=None, max_message_size=None,
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ssl_context=None, thread_class=None, event_class=None):
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parsed_url = urlsplit(url)
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is_secure = parsed_url.scheme in ['https', 'wss']
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self.host = parsed_url.hostname
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self.port = parsed_url.port or (443 if is_secure else 80)
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self.path = parsed_url.path
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if parsed_url.query:
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self.path += '?' + parsed_url.query
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self.subprotocols = subprotocols or []
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if isinstance(self.subprotocols, str):
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self.subprotocols = [self.subprotocols]
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self.extra_headeers = []
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if isinstance(headers, dict):
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for key, value in headers.items():
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self.extra_headeers.append((key, value))
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elif isinstance(headers, list):
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self.extra_headeers = headers
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sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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if is_secure: # pragma: no cover
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if ssl_context is None:
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ssl_context = ssl.create_default_context(
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purpose=ssl.Purpose.SERVER_AUTH)
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sock = ssl_context.wrap_socket(sock, server_hostname=self.host)
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sock.connect((self.host, self.port))
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super().__init__(sock, connection_type=ConnectionType.CLIENT,
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receive_bytes=receive_bytes,
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ping_interval=ping_interval,
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max_message_size=max_message_size,
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thread_class=thread_class, event_class=event_class)
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@classmethod
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def connect(cls, url, subprotocols=None, headers=None,
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receive_bytes=4096, ping_interval=None, max_message_size=None,
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ssl_context=None, thread_class=None, event_class=None):
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"""Returns a WebSocket client connection.
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:param url: The connection URL. Both ``ws://`` and ``wss://`` URLs are
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accepted.
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:param subprotocols: The name of the subprotocol to use, or a list of
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subprotocol names in order of preference. Set to
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``None`` (the default) to not use a subprotocol.
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:param headers: A dictionary or list of tuples with additional HTTP
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headers to send with the connection request. Note that
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custom headers are not supported by the WebSocket
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protocol, so the use of this parameter is not
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recommended.
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:param receive_bytes: The size of the receive buffer, in bytes. The
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default is 4096.
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:param ping_interval: Send ping packets to the server at the requested
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interval in seconds. Set to ``None`` (the
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default) to disable ping/pong logic. Enable to
|
|
prevent disconnections when the line is idle for
|
|
a certain amount of time, or to detect an
|
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unresponsive server and disconnect. A recommended
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interval is 25 seconds. In general it is
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preferred to enable ping/pong on the server, and
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let the client respond with pong (which it does
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regardless of this setting).
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:param max_message_size: The maximum size allowed for a message, in
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bytes, or ``None`` for no limit. The default
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is ``None``.
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:param ssl_context: An ``SSLContext`` instance, if a default SSL
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context isn't sufficient.
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:param thread_class: The ``Thread`` class to use when creating
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background threads. The default is the
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``threading.Thread`` class from the Python
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standard library.
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:param event_class: The ``Event`` class to use when creating event
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objects. The default is the `threading.Event``
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|
class from the Python standard library.
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"""
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return cls(url, subprotocols=subprotocols, headers=headers,
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receive_bytes=receive_bytes, ping_interval=ping_interval,
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max_message_size=max_message_size, ssl_context=ssl_context,
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thread_class=thread_class, event_class=event_class)
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def handshake(self):
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out_data = self.ws.send(Request(host=self.host, target=self.path,
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subprotocols=self.subprotocols,
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extra_headers=self.extra_headeers))
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self.sock.send(out_data)
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while True:
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in_data = self.sock.recv(self.receive_bytes)
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self.ws.receive_data(in_data)
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try:
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event = next(self.ws.events())
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except StopIteration: # pragma: no cover
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pass
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else: # pragma: no cover
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break
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if isinstance(event, RejectConnection): # pragma: no cover
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raise ConnectionError(event.status_code)
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elif not isinstance(event, AcceptConnection): # pragma: no cover
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raise ConnectionError(400)
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self.subprotocol = event.subprotocol
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self.connected = True
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def close(self, reason=None, message=None):
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super().close(reason=reason, message=message)
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self.sock.close()
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