I am using Laravel as my backend together with Sanctum which generates personal access token for mobile users. For my mobile application I am using flutter.
To authenticate users they login with their username/password and get a personal access token in return. This works but requires a user to login every time they open the application again so I did what most tutorials suggest which is saving the token on the mobile device using shared preferences/secure storage.
Now comes the question how do you invalidate a user when you remove their token from the backend? On initial login it appears everything is still fine because like in most tutorial I check for the existence of a token. After that whenever I want to make a request which uses the token I obviously run into problems because it not longer exists on the backend.
Most tutorials/guide suggest saving the token and using that a reference to see if the user is logged in or not but this seems flawed because it gives the false impression you actually have a valid token.
My guess is this can be solved by always performing a heartbeat/ping action to check if the current token is valid and if not send them to the login screen instead of simply checking for the existence of the token.
Thoughts on this?
