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328 lines
11 KiB
328 lines
11 KiB
from __future__ import annotations |
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import socket |
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import ssl |
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import threading |
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from typing import Any, Optional, Sequence, Type |
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from ..client import ClientProtocol |
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from ..datastructures import HeadersLike |
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from ..extensions.base import ClientExtensionFactory |
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from ..extensions.permessage_deflate import enable_client_permessage_deflate |
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from ..headers import validate_subprotocols |
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from ..http import USER_AGENT |
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from ..http11 import Response |
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from ..protocol import CONNECTING, OPEN, Event |
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from ..typing import LoggerLike, Origin, Subprotocol |
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from ..uri import parse_uri |
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from .connection import Connection |
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from .utils import Deadline |
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__all__ = ["connect", "unix_connect", "ClientConnection"] |
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class ClientConnection(Connection): |
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""" |
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Threaded implementation of a WebSocket client connection. |
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:class:`ClientConnection` provides :meth:`recv` and :meth:`send` methods for |
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receiving and sending messages. |
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It supports iteration to receive messages:: |
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for message in websocket: |
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process(message) |
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The iterator exits normally when the connection is closed with close code |
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1000 (OK) or 1001 (going away) or without a close code. It raises a |
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:exc:`~websockets.exceptions.ConnectionClosedError` when the connection is |
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closed with any other code. |
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Args: |
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socket: Socket connected to a WebSocket server. |
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protocol: Sans-I/O connection. |
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close_timeout: Timeout for closing the connection in seconds. |
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""" |
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def __init__( |
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self, |
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socket: socket.socket, |
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protocol: ClientProtocol, |
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*, |
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close_timeout: Optional[float] = 10, |
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) -> None: |
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self.protocol: ClientProtocol |
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self.response_rcvd = threading.Event() |
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super().__init__( |
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socket, |
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protocol, |
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close_timeout=close_timeout, |
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) |
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def handshake( |
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self, |
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additional_headers: Optional[HeadersLike] = None, |
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user_agent_header: Optional[str] = USER_AGENT, |
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timeout: Optional[float] = None, |
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) -> None: |
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""" |
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Perform the opening handshake. |
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""" |
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with self.send_context(expected_state=CONNECTING): |
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self.request = self.protocol.connect() |
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if additional_headers is not None: |
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self.request.headers.update(additional_headers) |
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if user_agent_header is not None: |
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self.request.headers["User-Agent"] = user_agent_header |
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self.protocol.send_request(self.request) |
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if not self.response_rcvd.wait(timeout): |
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self.close_socket() |
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self.recv_events_thread.join() |
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raise TimeoutError("timed out during handshake") |
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if self.response is None: |
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self.close_socket() |
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self.recv_events_thread.join() |
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raise ConnectionError("connection closed during handshake") |
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if self.protocol.state is not OPEN: |
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self.recv_events_thread.join(self.close_timeout) |
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self.close_socket() |
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self.recv_events_thread.join() |
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if self.protocol.handshake_exc is not None: |
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raise self.protocol.handshake_exc |
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def process_event(self, event: Event) -> None: |
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""" |
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Process one incoming event. |
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""" |
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# First event - handshake response. |
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if self.response is None: |
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assert isinstance(event, Response) |
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self.response = event |
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self.response_rcvd.set() |
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# Later events - frames. |
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else: |
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super().process_event(event) |
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def recv_events(self) -> None: |
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""" |
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Read incoming data from the socket and process events. |
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""" |
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try: |
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super().recv_events() |
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finally: |
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# If the connection is closed during the handshake, unblock it. |
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self.response_rcvd.set() |
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def connect( |
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uri: str, |
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*, |
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# TCP/TLS — unix and path are only for unix_connect() |
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sock: Optional[socket.socket] = None, |
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ssl_context: Optional[ssl.SSLContext] = None, |
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server_hostname: Optional[str] = None, |
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unix: bool = False, |
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path: Optional[str] = None, |
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# WebSocket |
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origin: Optional[Origin] = None, |
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extensions: Optional[Sequence[ClientExtensionFactory]] = None, |
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subprotocols: Optional[Sequence[Subprotocol]] = None, |
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additional_headers: Optional[HeadersLike] = None, |
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user_agent_header: Optional[str] = USER_AGENT, |
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compression: Optional[str] = "deflate", |
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# Timeouts |
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open_timeout: Optional[float] = 10, |
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close_timeout: Optional[float] = 10, |
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# Limits |
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max_size: Optional[int] = 2**20, |
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# Logging |
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logger: Optional[LoggerLike] = None, |
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# Escape hatch for advanced customization |
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create_connection: Optional[Type[ClientConnection]] = None, |
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) -> ClientConnection: |
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""" |
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Connect to the WebSocket server at ``uri``. |
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This function returns a :class:`ClientConnection` instance, which you can |
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use to send and receive messages. |
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:func:`connect` may be used as a context manager:: |
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async with websockets.sync.client.connect(...) as websocket: |
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... |
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The connection is closed automatically when exiting the context. |
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Args: |
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uri: URI of the WebSocket server. |
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sock: Preexisting TCP socket. ``sock`` overrides the host and port |
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from ``uri``. You may call :func:`socket.create_connection` to |
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create a suitable TCP socket. |
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ssl_context: Configuration for enabling TLS on the connection. |
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server_hostname: Host name for the TLS handshake. ``server_hostname`` |
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overrides the host name from ``uri``. |
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origin: Value of the ``Origin`` header, for servers that require it. |
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extensions: List of supported extensions, in order in which they |
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should be negotiated and run. |
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subprotocols: List of supported subprotocols, in order of decreasing |
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preference. |
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additional_headers (HeadersLike | None): Arbitrary HTTP headers to add |
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to the handshake request. |
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user_agent_header: Value of the ``User-Agent`` request header. |
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It defaults to ``"Python/x.y.z websockets/X.Y"``. |
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Setting it to :obj:`None` removes the header. |
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compression: The "permessage-deflate" extension is enabled by default. |
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Set ``compression`` to :obj:`None` to disable it. See the |
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:doc:`compression guide <../../topics/compression>` for details. |
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open_timeout: Timeout for opening the connection in seconds. |
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:obj:`None` disables the timeout. |
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close_timeout: Timeout for closing the connection in seconds. |
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:obj:`None` disables the timeout. |
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max_size: Maximum size of incoming messages in bytes. |
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:obj:`None` disables the limit. |
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logger: Logger for this client. |
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It defaults to ``logging.getLogger("websockets.client")``. |
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See the :doc:`logging guide <../../topics/logging>` for details. |
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create_connection: Factory for the :class:`ClientConnection` managing |
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the connection. Set it to a wrapper or a subclass to customize |
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connection handling. |
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Raises: |
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InvalidURI: If ``uri`` isn't a valid WebSocket URI. |
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OSError: If the TCP connection fails. |
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InvalidHandshake: If the opening handshake fails. |
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TimeoutError: If the opening handshake times out. |
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""" |
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# Process parameters |
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wsuri = parse_uri(uri) |
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if not wsuri.secure and ssl_context is not None: |
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raise TypeError("ssl_context argument is incompatible with a ws:// URI") |
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if unix: |
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if path is None and sock is None: |
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raise TypeError("missing path argument") |
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elif path is not None and sock is not None: |
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raise TypeError("path and sock arguments are incompatible") |
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else: |
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assert path is None # private argument, only set by unix_connect() |
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if subprotocols is not None: |
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validate_subprotocols(subprotocols) |
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if compression == "deflate": |
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extensions = enable_client_permessage_deflate(extensions) |
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elif compression is not None: |
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raise ValueError(f"unsupported compression: {compression}") |
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# Calculate timeouts on the TCP, TLS, and WebSocket handshakes. |
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# The TCP and TLS timeouts must be set on the socket, then removed |
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# to avoid conflicting with the WebSocket timeout in handshake(). |
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deadline = Deadline(open_timeout) |
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if create_connection is None: |
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create_connection = ClientConnection |
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try: |
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# Connect socket |
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if sock is None: |
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if unix: |
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
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sock.settimeout(deadline.timeout()) |
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assert path is not None # validated above -- this is for mpypy |
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sock.connect(path) |
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else: |
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sock = socket.create_connection( |
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(wsuri.host, wsuri.port), |
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deadline.timeout(), |
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) |
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sock.settimeout(None) |
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# Disable Nagle algorithm |
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if not unix: |
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sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True) |
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# Initialize TLS wrapper and perform TLS handshake |
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if wsuri.secure: |
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if ssl_context is None: |
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ssl_context = ssl.create_default_context() |
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if server_hostname is None: |
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server_hostname = wsuri.host |
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sock.settimeout(deadline.timeout()) |
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sock = ssl_context.wrap_socket(sock, server_hostname=server_hostname) |
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sock.settimeout(None) |
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# Initialize WebSocket connection |
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protocol = ClientProtocol( |
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wsuri, |
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origin=origin, |
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extensions=extensions, |
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subprotocols=subprotocols, |
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state=CONNECTING, |
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max_size=max_size, |
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logger=logger, |
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) |
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# Initialize WebSocket protocol |
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connection = create_connection( |
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sock, |
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protocol, |
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close_timeout=close_timeout, |
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) |
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# On failure, handshake() closes the socket and raises an exception. |
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connection.handshake( |
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additional_headers, |
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user_agent_header, |
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deadline.timeout(), |
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) |
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except Exception: |
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if sock is not None: |
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sock.close() |
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raise |
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return connection |
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def unix_connect( |
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path: Optional[str] = None, |
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uri: Optional[str] = None, |
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**kwargs: Any, |
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) -> ClientConnection: |
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""" |
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Connect to a WebSocket server listening on a Unix socket. |
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This function is identical to :func:`connect`, except for the additional |
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``path`` argument. It's only available on Unix. |
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It's mainly useful for debugging servers listening on Unix sockets. |
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Args: |
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path: File system path to the Unix socket. |
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uri: URI of the WebSocket server. ``uri`` defaults to |
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``ws://localhost/`` or, when a ``ssl_context`` is provided, to |
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``wss://localhost/``. |
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""" |
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if uri is None: |
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if kwargs.get("ssl_context") is None: |
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uri = "ws://localhost/" |
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else: |
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uri = "wss://localhost/" |
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return connect(uri=uri, unix=True, path=path, **kwargs)
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