users logged in script

[csun]

hello,

i have a startup a website, and i use php with a mysql backend to store information.

my question is, how can i create a "users logged in now" script? i want to have the "users logged in now" part of the site dynamic, instead of having to purge the user login cache (login information is stored as a 1 or 0 in user database)?

right now, when a user logs in, the login field on his database entry becomes 1, but if he doesnt log out by clicking "logout" (i.e. he closes the browser window) he remains "logged in." i only want to show people who are logged in (and clicking) at the time the page is loaded.

thnx

[csun]

i would like to echo different links on each page depending on if the user is logged on or not,

e.g "log on" or "register" if they are not and "change style" if they are,

how do i do this?

thanks

[gimmie]

sessions...

i think

[masonbarge]

Do you want to require users to accept cookies? If so, that's the easy answer. Use sessions and cookies.

If not, you're faced with the problem of transmitting the session id. I'm about to post a question about doing this with $_POST forms. Otherwise AFAIK, you pretty much have to put the session id in the url.

Another approach is to query the member table on each page load, which depends on how much server load you can tolerate.

Unless you want some complex mechanism that will detect the browser's exit, I don't know of any way to log someone out accurately. A lot of sites put a timer on the session. Some allow the user to choose "log me out after * minutes" or "keep me logged in", although I image the latter option generally has a 12 or 24 hour timer or gets caught in a periodic sweep.

[Accurax]

question :.... do sessions expire naturally?..... if so, how long does this take, and if not what are the consequences of not killing them properly?