Users online

[sidsel]

My site use sessions and have an option for users to login.
Is there a way I can make a listing of all users that are logged in and are active on the site?

I could store the username in a table then they log in but how do I keep track of users who are leaving the site without logging out?

Can I in some way use the sessions in the tmp dir to do this?

[bradgrafelman]

Along with the username, store the timestamp of their last activity in the DB. Every time they click on a page, or do anything, you'd run a query similar to:

$query = 'UPDATE `usersOnline` SET `timestamp` = UNIX_TIMESTAMP() WHERE `username` = \'' . $_SESSION['username'] . '\' LIMIT 1';

That way, when you're SELECT'ing users to display that are "online", you would add an additional WHERE clause similar to:

WHERE `timestamp` > (UNIX_TIMESTAMP() - 900)

(900 seconds = 15 minutes).

Periodically, you would want to DELETE from the table where the timestamps are too old.

Alternatively, there are plenty of pre-made scripts that can do this. Check out either HotScripts or Google it.