on | SignalWire

Register a listener for events on this call. The handler is called each time an event of the specified type is received. Handlers can be regular functions or async coroutines.

Parameters

event_type

strRequired

The event type string to listen for (e.g., "calling.call.state", "calling.call.play"). See the Events section on the Call page for class-level events, or individual method pages for method-specific events.

handler

Callable[[RelayEvent], Any]Required

Function or coroutine to invoke when the event fires. Receives a RelayEvent instance.

Returns

None

Example

1 from signalwire.relay import RelayClient
2 
3 client = RelayClient(
4     project="your-project-id",
5     token="your-api-token",
6     host="your-space.signalwire.com",
7     contexts=["default"],
8 )
9 
10 @client.on_call
11 async def handle_call(call):
12     await call.answer()
13 
14     # Register a listener for play events
15     call.on("calling.call.play", lambda event: print(f"Play state: {event.params.get('state')}"))
16 
17     # Register a listener for state changes
18     def on_state_change(event):
19         print(f"Call state changed: {event.params.get('call_state')}")
20 
21     call.on("calling.call.state", on_state_change)
22 
23     action = await call.play([{"type": "tts", "text": "Hello!"}])
24     await action.wait()
25 
26 client.run()