Method encode_message

cassandra/protocol.py:1110–1145

Encodes a message using the specified frame parameters, and compressor :param msg: the message, typically of cassandra.protocol._MessageType, generated by the driver :param stream_id: protocol stream id for the frame header :param protocol_version: version for the f

(cls, msg, stream_id, protocol_version, compressor, allow_beta_protocol_version)

    @classmethod
    def encode_message(cls, msg, stream_id, protocol_version, compressor, allow_beta_protocol_version):
        """
        Encodes a message using the specified frame parameters, and compressor

        :param msg: the message, typically of cassandra.protocol._MessageType, generated by the driver
        :param stream_id: protocol stream id for the frame header
        :param protocol_version: version for the frame header, and used encoding contents
        :param compressor: optional compression function to be used on the body
        """
        flags = 0
        body = io.BytesIO()
        if msg.custom_payload:
            if protocol_version < 4:
                raise UnsupportedOperation("Custom key/value payloads can only be used with protocol version 4 or higher")
            flags |= CUSTOM_PAYLOAD_FLAG
            write_bytesmap(body, msg.custom_payload)
        msg.send_body(body, protocol_version)
        body = body.getvalue()

        # With checksumming, the compression is done at the segment frame encoding
        if (not ProtocolVersion.has_checksumming_support(protocol_version)
                and compressor and len(body) > 0):
            body = compressor(body)
            flags |= COMPRESSED_FLAG

        if msg.tracing:
            flags |= TRACING_FLAG

        if allow_beta_protocol_version:
            flags |= USE_BETA_FLAG

        buff = io.BytesIO()
        cls._write_header(buff, protocol_version, flags, stream_id, msg.opcode, len(body))
        buff.write(body)

        return buff.getvalue()

    @staticmethod
    def _write_header(f, version, flags, stream_id, opcode, length):