Incoming message structure

The @app.listen decorator is used to create a listener for messages sent to the specified NATS subject.

@app.listen(subject='some.subject')
async def subject_for_requests_listener(msg):
    subject = msg.subject
    message = msg.data
    # handle incoming message

When a message is received, the msg object is passed to the callback function. This object contains the following properties:

• msg.subject (str): The NATS subject that the message was sent from.
• msg.data (dict or str or bytes): Analogue of the body of an HTTP message.
• msg.reply (str): A one-time use subject to send a response.
• msg.sid (str): The subscribe ID that the message was sent from.
• msg.headers (dict): A dictionary containing any custom headers set externally.