Site Access

Preventing Loggin-in On the Same Instance

[Francis]

Hello again.

Is there a way how to prevent two people from different locations from accessing a site using the same username and password combination using PHP.

For example, if I am currently logged-in here in Webmasterworld using my username and password, nobody should be able to log-in using the same username and password combination.

How can that be done using PHP?

Thanks a bunch

[mincklerstraat]

You'll have to use sessions of some kind, either standard php sessions or your own type of sessions. Put some kind of hash (check out md5 functions) of username/password combination into your db along with the session name whenever a user logs in, make it clear that logging out is a 'must' for users so you don't get problems with this table 'locking' things up (destroy cookie and also db record when logging out) - and also check, when a user tries to log in, if the username/password hash he's trying to use is already in the db (obviously, before putting it in there). Probably will also want to add some kind of time element - check with each login, destroying expired session rows, and update this table with each pageview with the current time. All in all, a bit complicated.

Otherwise, see if any of the authentication scripts out there, like on pear.php.net or pat-user, have some kind of feature like you're describing.