get a list of online users in asp.net mvc

Question

I have a page in my application which always shows updated list of online users. Now, to keep the list-which is stored in application object- updated, i do the below steps

Answer 1

Do the following inside a global filter.

public class TrackLoginsFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Dictionary loggedInUsers = SecurityHelper.GetLoggedInUsers();

        if (HttpContext.Current.User.Identity.IsAuthenticated )
        {
            if (loggedInUsers.ContainsKey(HttpContext.Current.User.Identity.Name))
            {
                loggedInUsers[HttpContext.Current.User.Identity.Name] = System.DateTime.Now;
            }
            else
            {
                loggedInUsers.Add(HttpContext.Current.User.Identity.Name, System.DateTime.Now);
            }

        }

        // remove users where time exceeds session timeout
        var keys = loggedInUsers.Where(u => DateTime.Now.Subtract(u.Value).Minutes >
                   HttpContext.Current.Session.Timeout).Select(u => u.Key);
        foreach (var key in keys)
        {
            loggedInUsers.Remove(key);
        }

    }
}

To retrieve the user list

public static class SecurityHelper
{
    public static Dictionary GetLoggedInUsers()
    {
        Dictionary loggedInUsers = new Dictionary();

        if (HttpContext.Current != null)
        {
            loggedInUsers = (Dictionary)HttpContext.Current.Application["loggedinusers"];
            if (loggedInUsers == null)
            {
                loggedInUsers = new Dictionary();
                HttpContext.Current.Application["loggedinusers"] = loggedInUsers;
            }
        }
        return loggedInUsers;

    }
}

Don't forget to Register you filter in global.asax. It's probably a good idea to have an app setting to switch this off.

GlobalFilters.Filters.Add(new TrackLoginsFilter());

Also remove users at logoff to be more accurate.

SecurityHelper.GetLoggedInUsers().Remove(WebSecurity.CurrentUserName);