Member based website - telling who is online?

Jsn7821

I have a member based website, and when a user logs on it sets online = 1 in the database, and when they log off it sets it to = 0.

When they close the window, they automatically log off... the session closes. How can I let the database know this? Is there a way I can have the online column automatically turn to 0 after 30 minutes of inactivity or something? Would I need to set up a cron job on the server (I pay for hosting, dont know if I can even do that).

Thanks

laserlight

Basically, you need to record the time of each user's last activity (i.e. page load). If the difference between the current time and that recorded time is greater than 30 minutes, you consider the user as having logged off. A cron job could be run to check for this, but alternatively you could get the script that displays the list of logged in users to do this check.

Jsn7821

Is it a bad idea to run cron jobs very often? Does it put unncessisary load on the server?

Weedpacket

How often is "very often"? 30 minutes certainly isn't. Besides, it depends on what the job is doing.

TruckStuff

Jsn7821 wrote:
Is it a bad idea to run cron jobs very often? Does it put unncessisary load on the server?

What WP said. It really depends on what the script is doing. For example, I've got a cron job that funs every 10 minutes to update our mail server's list of allowed users. It takes <2 seconds to run. We have some other cron jobs that run daily and can take as much as 2 hours to complete. However, it is mostly remote mysql queries, so the load on the local machine isn't very much.