Posted by David Haynes on 11/18/22 11:40

Mickey wrote:
> Hi all,
>
> Currently I use a timestamp to log users out after 15 minutes of
> inactivity.
> However I also need to log a user out if they have just left the page.
> I need to do this because I store current online users in a database,
> allowing a maximum of 5 users at one time.
>
> I have been looking through the php manual and came across
> session_cache_expire(). This isn't doing what I need either. Am I
> going in the wrong direction with this?
>
> Basically my question is, is there a way to log a user out (and clear
> my user_online database) if they just leave the page?
>
> Thanks in advance for any suggestions.
>
The short answer is 'no'.

If a user goes to another page via the browser, then there is no
conversation with your server. So there is no way for your server to
know that the user has left.

Think of it as if your server is receiving mail. You know when you get a
letter, you can tell the time since you last got a letter and you can
reply to a letter, but there is no way to know that the user has also
written a letter to someone else.

Now, if you keep the 'last heard from' timestamp in a database, you may
release a session based upon a last response time (i.e. fifteen minutes)
without having to hear from the browser at all. (i.e. no cookie exchange
is required) Its not the same as detecting that they have gone elsewhere
but is probably the best you can do.

-david-

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