Users still "active"

[Herten]

Hey guys,

I've developed a PHP web application, where users must login to use it. I'd like to let them view who's currently "online" in the application.

I've thought of using sessions since I already use them to store some user's information, but I don't know how to
1) view all active sessions
2) check when a user leaves the application by closing the window or browsing into another site, without "logging out" properly from the application.

I've thought of looking at the session directory, but even when users are getting out of the application, the sess_sessionID file remains there with session values in it...

Any idea anyone ?

Thanks a great deal, I'm quite desperate here...
Herten

[planetsim]

Make a new feild with time and status

so make that 2 new feilds in the members table

$time=time();
thats when they login
keep updating the members time on every page and keep status online if the time still exists

now from there.

you'll need to see if there offline

we do this by adding another function to each page

$timeout=time()-500;
mysql_query("UPDATE tbl_name WHERE time < $timeout");
or use DELETE if it doesnt need that record of information again.

[Herten]

Thanks a lot Planetsim for the nice idea.

Now I fear that these tasks must be costy in performance ? For the moment I have about 30 users in the application, but I expect this number to raise a lot in the very near future...
If I understood your idea right, EACH page will have to do all the following tasks (I guess I better put all this in a single page which then will be included everywhere) :

• update the current user's Time column in a database with current time (time() ), as well as it's status column (like status = 1 or something)
• update all user's status in Database according to whether timeout is reached or not (so status will be 0 for offline users and 1 for online users).
• access the database again with a "SELECT Username FROM Table where Status =1" to display all currently users...

This makes 3 Database access per page...
Furthermore, we're using MS SQL 2000 here on another server, so I guess (not sure at all though) that database access might be a little bit slower than mysql....

I was hoping for a more "native PHP session" solution ? Is this the only way to achieve this ?

See ya
Herten

[Weedpacket]

No: you don't need that extra "online" field, or the query to update it. All the information that would have been in that field can be derived from the information in the "time" field. A user is "online" if and only if now()-time is less than 500 seconds.

You don't need to worry about needing the extra column if they can log out explicitly, either; just set the "time" field to a time that is definitely more than 500 seconds ago.

What you're looking at is a deliberate limitation of the http protocol - the server doesn't remember clients from one request to the next, and keeps no persistent connection open between requests. So it can't tell the difference between a silent client and one that is completely absent.

[ereptur]

One thing I've done on my website is a active box that shows users that were online within the last 15 minutes. The way I do this is a query like the following:

$query = "select user from users where lastin >= date_sub(now(),interval 15 minute)";

On each page it updates the user's lastin to now();

[Herten]

Ok I see more clearly what you mean, Weedpacket.

Thanks to you and also to Ereptur for the nice Query. Starting the work right now 🙂

See ya
Herten