How to implement session timeout logic
The session timeout logic can be implemented on the server-side, the client-side, or both. The server-side session timeout logic is more secure, because it controls the validity and expiration of the session tokens or cookies on the server, and it does not depend on the user's browser settings or actions. However, the server-side session timeout logic may not be able to detect the user's inactivity or idle time accurately, because it only tracks the user's requests to the server, not the user's interactions with the web page. Therefore, the server-side session timeout logic may expire the session while the user is still active on the web page, or keep the session alive while the user has left the web page.
The client-side session timeout logic is less secure, because it relies on the user's browser to store and manage the session tokens or cookies, and it can be manipulated or bypassed by malicious users or scripts. However, the client-side session timeout logic can provide a better user experience, because it can monitor the user's activity and idle time on the web page, and it can warn or prompt the user before the session expires. Therefore, the client-side session timeout logic can prevent the session from expiring unexpectedly, or allow the user to extend or renew the session without re-authenticating.
The best practice is to use a combination of both server-side and client-side session timeout logic, to achieve both security and usability. The server-side session timeout logic should set a reasonable and consistent session expiration time, and invalidate the session tokens or cookies when they expire. The client-side session timeout logic should synchronize with the server-side session timeout logic, and display a countdown timer, a warning message, or a session extension option to the user, before the session expires. The client-side session timeout logic should also use secure and encrypted methods to store and communicate the session tokens or cookies with the server, and avoid exposing them to third-party scripts or domains.