Provide a means of changing client username

[Surgbc]

I have come across a situation where it is necessary to change the username used to authenticate the client. I am implementing a system where a user logs in using either (1) username and password (2) webtoken obtained from authentication done by the client itself. Since the username user and the webtoken user are one and the same, I require to change the client username to userId which is the same regardless of how the client authenticates.

I have so far managed to do it this way:

1. Changing the auth interface
   Authenticate(user, password []byte) (interface{}, error)

2. Obtaining new username and assigning to client during authentication

	// if !ac.Authenticate(pk.Username, pk.Password) {
	// 	if err := s.ackConnection(cl, packets.CodeConnectBadAuthValues, false); err != nil {
	// 		return s.onError(cl.Info(), fmt.Errorf("invalid connection send ack: %w", err))
	// 	}
	// 	return s.onError(cl.Info(), ErrConnectionFailed)
	// }
	username, err := ac.Authenticate(pk.Username, pk.Password)
	if err != nil {
		if err := s.ackConnection(cl, packets.CodeConnectBadAuthValues, false); err != nil {
			return s.onError(cl.Info(), fmt.Errorf("invalid connection send ack: %w", err))
		}
		return s.onError(cl.Info(), ErrConnectionFailed)
	}
	if username != nil {
		pk.Username = []byte(username.(string))
		cl.Identify(lid, pk, ac)
	}

Is this a feature you could consider?

[mochi-co]

Hi @Surgbc - this feature will be available in v2.0.0. V2 is nearly ready (just working out some of the finer details of mqtt v5) 👍🏻

[mochi-co]

This issue has been resolved in v2.0.0 through the implementation of universal hooks. You should be able to set the client.ID value in OnConnect or OnConnectAuthenticate as client is a pointer. Let me know if it doesn't behave as expected.

[Surgbc]

Great!