How to feed mqtt messages from within a fastapi websocket ? (ie. proxying) about fastapi-mqtt HOT 1 CLOSED

Hi @MoonCactus,

The @mqttclient.on_subscribe() callback will trigger just to confirm the subscription is OK, but all received MQTT messages will pass through @mqttclient.on_message() 😜. It is there where you have to dispatch the received msgs in all subscribed topics to the open web sockets that match.

It is not a problem to make dynamic subscriptions and unsubscriptions, if you want to avoid listening to "xxx/#", but I imagine you would have to manage those separately, to avoid multiple subscriptions to the same topic (like: when opening the ws, check if already subscribed to topic, and subscribe only if not; and when closing the connection, do the opposite)

Then, by using some kind of async queue, you could dispatch the new MQTT messages through the ws connections as they come (Take a look to https://github.com/smithk86/asyncio-multisubscriber-queue).

I did something similar in the recent past (sorry, not open source), but using server-sent-events instead of ws, and without the need of dynamic subscriptions, using that library to manage the current connections. It may serve as inspiration for you (but I imagine you already solved your problem, right?)

from fastapi-mqtt.