declearn.communication.utils.verify_server_message_validity

Verify that a received serialized message matches expected type.

• If the received message matches expected type, deserialize it.
• If the recevied message is an unexpected Error message, raise.
• If it belongs to any other type, send an Error to the server, then raise.

Parameters:

Name	Type	Description	Default
netwk	NetworkClient	NetworkClient endpoint, from which the processed message was received.	required
received	SerializedMessage	Received SerializedMessage to type-check and deserialize.	required
expected	Type[MessageT]	Expected Message subtype. Any subclass will be considered as valid.	required

Returns:

Name	Type	Description
message	MessageT	Deserialized Message from received, with expected type.

Raises:

Type	Description
ErrorMessageException	If received wraps an unexpected Error message.
MessageTypeException	If received wrapped message does not match expected type.

Source code in declearn/communication/utils/_parse.py

async def verify_server_message_validity(
    netwk: NetworkClient,
    received: SerializedMessage,
    expected: Type[MessageT],
) -> MessageT:
    """Verify that a received serialized message matches expected type.

    - If the received message matches expected type, deserialize it.
    - If the recevied message is an unexpected `Error` message, raise.
    - If it belongs to any other type, send an `Error` to the server,
      then raise.

    Parameters
    ----------
    netwk:
        `NetworkClient` endpoint, from which the processed message
        was received.
    received:
        Received `SerializedMessage` to type-check and deserialize.
    expected:
        Expected `Message` subtype. Any subclass will be considered
        as valid.

    Returns
    -------
    message:
        Deserialized `Message` from `received`, with `expected` type.

    Raises
    ------
    ErrorMessageException
        If `received` wraps an unexpected `Error` message.
    MessageTypeException
        If `received` wrapped message does not match `expected` type.
    """
    # If a proper message is received, deserialize and return it.
    if issubclass(received.message_cls, expected):
        return received.deserialize()
    # When an Error is received, merely raise using its content.
    error = f"Expected a '{expected}' message"
    if issubclass(received.message_cls, Error):
        msg = received.deserialize()
        error = f"{error}, received an Error message: '{msg.message}'."
        raise ErrorMessageException(error)
    # Otherwise, send an Error to the server, then raise.
    error = f"{error}, got a '{received.message_cls}'."
    await netwk.send_message(Error(error))
    raise MessageTypeException(error)