Method decode_message

cassandra/protocol.py:1157–1213

Decodes a native protocol message body :param protocol_version: version to use decoding contents :param user_type_map: map[keyspace name] = map[type name] = custom type to instantiate when deserializing this type :param stream_id: native protocol stream id from the

(cls, protocol_version, user_type_map, stream_id, flags, opcode, body,
                       decompressor, result_metadata)

    @classmethod
    def decode_message(cls, protocol_version, user_type_map, stream_id, flags, opcode, body,
                       decompressor, result_metadata):
        """
        Decodes a native protocol message body

        :param protocol_version: version to use decoding contents
        :param user_type_map: map[keyspace name] = map[type name] = custom type to instantiate when deserializing this type
        :param stream_id: native protocol stream id from the frame header
        :param flags: native protocol flags bitmap from the header
        :param opcode: native protocol opcode from the header
        :param body: frame body
        :param decompressor: optional decompression function to inflate the body
        :return: a message decoded from the body and frame attributes
        """
        if (not ProtocolVersion.has_checksumming_support(protocol_version) and
                flags & COMPRESSED_FLAG):
            if decompressor is None:
                raise RuntimeError("No de-compressor available for compressed frame!")
            body = decompressor(body)
            flags ^= COMPRESSED_FLAG

        body = io.BytesIO(body)
        if flags & TRACING_FLAG:
            trace_id = UUID(bytes=body.read(16))
            flags ^= TRACING_FLAG
        else:
            trace_id = None

        if flags & WARNING_FLAG:
            warnings = read_stringlist(body)
            flags ^= WARNING_FLAG
        else:
            warnings = None

        if flags & CUSTOM_PAYLOAD_FLAG:
            custom_payload = read_bytesmap(body)
            flags ^= CUSTOM_PAYLOAD_FLAG
        else:
            custom_payload = None

        flags &= USE_BETA_MASK  # will only be set if we asserted it in connection estabishment

        if flags:
            log.warning("Unknown protocol flags set: %02x. May cause problems.", flags)

        msg_class = cls.message_types_by_opcode[opcode]
        msg = msg_class.recv_body(body, protocol_version, user_type_map, result_metadata, cls.column_encryption_policy)
        msg.stream_id = stream_id
        msg.trace_id = trace_id
        msg.custom_payload = custom_payload
        msg.warnings = warnings

        if msg.warnings:
            for w in msg.warnings:
                log.warning("Server warning: %s", w)

        return msg