How can I tell how long a user was logged in?

Question

Please note that I don't want to know the interval between logins - I want to know how many minutes (or hours) elapsed between a login and the subsequent logout. Is it possible to calculate this in SFDC, using any combination of technologies?

Answer 1

The logout times are not recorded so unless you wrote a browser extension or tied a JavaScript event to the click of the logout button , im afraid it isn't possible to retrospectively calculate the logged in duration of the user.

You could have a sort of 'heartbeat' embedded in the sidebar running as a JavaScript polled job I suppose which kept writing / updating a user specific record in a custom object ever so often while a user was logged in. Every time a user logged out there would be a significant pause in the writing of these 'active' records .

Answer 2

Open your debug log and paste this :

You can create a page use this as a controller and display the difference to the user(or) use it apex code as a method:

List<Loginhistory> login = [SELECT UserId, LoginTime from LoginHistory where userid=: userinfo.getuserid() and logintime = today order by logintime asc];
    decimal  numberofhours;
    decimal numberofmiuntes;
    integer size = login.size();
    numberofhours = ( system.now().hour() - login[size-1].LoginTime.hour()  );
    numberofmiuntes = (system.now().gettime() - login[size-1].LoginTime.gettime())/60000;  
    system.debug('Hours: '+numberofhours + ' Minutes:'+ numberofmiuntes);