Protocol Gateway: Possiblity to use Gateway as MQTT Topic mapper

[julian-sotec]

Background:
Devices that connect to an MQTT Broker may rely on a fixed topic structure which cannot be changed.
We want to provide a configurable MQTT Topic mapping for a number of MQTT Topics to hono internal MQTT Topics.
Our Idea would be:

• Implement a protocol gateway with configurable mqtt topic mapping unsing the template
• Implement (Re-Use) the same Authentication mechanism that Hono provides on the MQTT Adapter
• Implement routing of configured topics to correct hono internal MQTT topics for authenticated devices
• Implement command & response handling (as it exists in the current template using correlation id mechanism)

Flow would be:

1. Configure topic mapping as configuration
2. Device authenticates to new protocol gateway using one of the configured topics
3. Gateway maps incoming MQTT Message or Command to hono's internal MQTT Topic for authenticated devices based on configuration

Our questions would be:
Does this approach make sense from a protocol gateway point of view?