Keeping track of users online

[stovellp]

How does this site keep track of the users browsing the forum? Like, how does it know that a user is looking at a page or not? I guess it could add their name to a file when it serves a file to them, but what about when they leave it? How would that work?

Just curious

~ Paul

[trexx]

i'm not sure how exactly they implemented that, but i guess that it is done by a session-ID for every user that is logged in.
the users are stored in a DB table and with each request you update the timestamp that belongs to them. Now you define a timeout (i.e. 5 minutes) and select all users with a timestamp larger than (now() - 5 minutes). and there you have them 😃

[stovellp]

Ahhh I see... very clever indeed... I never thought of using a timer like that... thank you very much!

~ Paul