on | SignalWire

Register an event listener for state changes on this message. The handler is called each time a messaging.state event is received for this message, allowing you to react to intermediate states before the terminal state is reached.

Parameters

handler

Callable[[RelayEvent], None]Required

A function or coroutine that receives a RelayEvent on each state change. Both synchronous and async handlers are supported.

Returns

None

Example

1 import asyncio
2 from signalwire.relay import RelayClient
3 
4 client = RelayClient(
5     project="your-project-id",
6     token="your-api-token",
7     host="your-space.signalwire.com",
8     contexts=["default"],
9 )
10 
11 async def track_state():
12     async with client:
13         message = await client.send_message(
14             to_number="+15551234567",
15             from_number="+15559876543",
16             body="Order confirmed",
17         )
18 
19         def on_state_change(event):
20             print(f"Message {message.message_id} -> {message.state}")
21 
22         message.on(on_state_change)
23         await message.wait()
24 
25 asyncio.run(track_state())