MqttTransport.on

MqttTransport.on(event, f=None)

Registers the function (or optionally an asyncio coroutine function) f to the event name event.

If f isn’t provided, this method returns a function that takes f as a callback; in other words, you can use this method as a decorator, like so:

@ee.on('data')
def data_handler(data):
    print(data)

As mentioned, this method can also take an asyncio coroutine function:

@ee.on('data')
async def data_handler(data)
    await do_async_thing(data)

This will automatically schedule the coroutine using the configured scheduling function (defaults to asyncio.ensure_future) and the configured event loop (defaults to asyncio.get_event_loop()).

In both the decorated and undecorated forms, the event handler is returned. The upshot of this is that you can call decorated handlers directly, as well as use them in remove_listener calls.