Open codepitbull opened 1 year ago
Hi @codepitbull - if I'm not mistaken, topic alias are enabled and utilised by default without user intervention. It's a smart move for performance.
This should be documented to be made evident.
Yes, but in my request I talk specifically aout specifying those directly. I am currently analysing cases in which I need to recreate topic-mappings on a different socket. None of the information around mappings is available on the objects and I need to know and control the Topic Mappings created.
An example for how Paho is doing it:
The MqttProperties are available on every PUBLISH/PUBACK:
@codepitbull not exposing the topic aliases was an intentional decision. Topic aliases are only valid in the scope of a single connection. Before I go into too much details, I would like to understand what you are trying to achieve.
I am currently analysing cases in which I need to recreate topic-mappings on a different socket.
What do you mean by "recreating topic-mappings"? Proxy an MQTT connection? Then you have 2 connections that each should negotiate its own topic aliases. If the proxy alters or discards any messages, then reusing topic aliases would not be safe. If you want to proxy 1:1, then proxy the binary traffic. Before we can label this as a feature request, we need to understand what you want to achieve.
🚀 Feature Request
Going through the API I can't find a way to specify or receive an MQTT 5 topic alias. This is weird since the connection parameters for controlling them are there.
🔈 Motivation
There should be a way to provide a topic alias for a PUBLISH-message. There should be a way to read the topic alias returned from the broker in PUBACK.