Method write_message

python/python3/tornado/websocket.py:311–339

Sends the given message to the client of this Web Socket. The message may be either a string or a dict (which will be encoded as json). If the ``binary`` argument is false, the message will be sent as utf8; in binary mode any byte string is allowed. If the

(
        self, message: Union[bytes, str, Dict[str, Any]], binary: bool = False
    )

        )

    def write_message(
        self, message: Union[bytes, str, Dict[str, Any]], binary: bool = False
    ) -> "Future[None]":
        """Sends the given message to the client of this Web Socket.

        The message may be either a string or a dict (which will be
        encoded as json).  If the ``binary`` argument is false, the
        message will be sent as utf8; in binary mode any byte string
        is allowed.

        If the connection is already closed, raises `WebSocketClosedError`.
        Returns a `.Future` which can be used for flow control.

        .. versionchanged:: 3.2
           `WebSocketClosedError` was added (previously a closed connection
           would raise an `AttributeError`)

        .. versionchanged:: 4.3
           Returns a `.Future` which can be used for flow control.

        .. versionchanged:: 5.0
           Consistently raises `WebSocketClosedError`. Previously could
           sometimes raise `.StreamClosedError`.
        """
        if self.ws_connection is None or self.ws_connection.is_closing():
            raise WebSocketClosedError()
        if isinstance(message, dict):
            message = tornado.escape.json_encode(message)
        return self.ws_connection.write_message(message, binary=binary)

    def select_subprotocol(self, subprotocols: List[str]) -> Optional[str]:
        """Override to implement subprotocol negotiation.