I need to test MQTT 5 messages with protobuf-encoded contents. Which brotobuf file to be used in order to convert their contents in plain text and vice versa, is transferred by an user property of each message.
From the Karate docs and this post I know, there must be a way to extend Karate's capabilities for such purposes through external libraries. I think, HiveMQ MQTT Client and protocolbuffers/protobuf from Google could be used for this. But I have no idea of how to get started.
It would be great if anyone could sketch the approach in more detail or point me to a similar example. My Java skills are poor, so any hints are appreciated.