[Websockets with fastapi] #fastapi #websockets

websocket.py

# https://github.com/tiangolo/fastapi/issues/883#issuecomment-575913215
# You can probably use an async queue so your MQTT client will push messages to the queue and the WS server will get from the queue and send them to the WS client.

    from asyncio import Queue

    queue: Queue = None

    @app.websocket("/ws")
    async def websocket_endpoint(websocket: WebSocket):
        await websocket.accept()
        global queue
        queue = Queue()
        while True:
            msg = await queue.get()
            await websocket.send_text({"message": msg})


    async def on_mqtt_message(msg):
        if queue:
          await queue.put(msg)
          
# Note that the queue must be using the same event-loop as the WS, one way of doing it is to initialize the queue in the same function where you accept the WS.
# Also, assuming you want the WS client to receive all the MQTT messages, you should use a queue per WS.