Class ClientProtocol

src/websockets/client.py:48–341

Sans-I/O implementation of a WebSocket client connection. Args: uri: URI of the WebSocket server, parsed with :func:`~websockets.uri.parse_uri`. origin: Value of the ``Origin`` header. This is useful when connecting to a server that validates the ``O

class ClientProtocol(Protocol):
    """
    Sans-I/O implementation of a WebSocket client connection.

    Args:
        uri: URI of the WebSocket server, parsed
            with :func:`~websockets.uri.parse_uri`.
        origin: Value of the ``Origin`` header. This is useful when connecting
            to a server that validates the ``Origin`` header to defend against
            Cross-Site WebSocket Hijacking attacks.
        extensions: List of supported extensions, in order in which they
            should be tried.
        subprotocols: List of supported subprotocols, in order of decreasing
            preference.
        state: Initial state of the WebSocket connection.
        max_size: Maximum size of incoming messages in bytes.
            :obj:`None` disables the limit. You may pass a ``(max_message_size,
            max_fragment_size)`` tuple to set different limits for messages and
            fragments when you expect long messages sent in short fragments.
        logger: Logger for this connection;
            defaults to ``logging.getLogger("websockets.client")``;
            see the :doc:`logging guide <../../topics/logging>` for details.

    """

    def __init__(
        self,
        uri: WebSocketURI,
        *,
        origin: Origin | None = None,
        extensions: Sequence[ClientExtensionFactory] | None = None,
        subprotocols: Sequence[Subprotocol] | None = None,
        state: State = CONNECTING,
        max_size: int | None | tuple[int | None, int | None] = 2**20,
        logger: LoggerLike | None = None,
    ) -> None:
        super().__init__(
            side=CLIENT,
            state=state,
            max_size=max_size,
            logger=logger,
        )
        self.uri = uri
        self.origin = origin
        self.available_extensions = extensions
        self.available_subprotocols = subprotocols
        self.key = generate_key()

    def connect(self) -> Request:
        """
        Create a handshake request to open a connection.

        You must send the handshake request with :meth:`send_request`.

        You can modify it before sending it, for example to add HTTP headers.

        Returns:
            WebSocket handshake request event to send to the server.