Helpful ASP.NET forms authenication and session timeout article

From Adam Tuliper's Development Tips

What happens when user session timeouts before Form authenication does?

http://completedevelopment.blogspot.com/2009/12/caution-with-using-sessiontimeout-and.html

Modifield code from Adam's article:

Add the following code to global.asax to reroute request to login if session has expired:

protected void Application_PreRequestHandlerExecute(object sender, EventArgs e)
        {
            //Only access session state if it is available
            if (Context.Handler is IRequiresSessionState || Context.Handler is IReadOnlySessionState)
            {
                //If we are authenticated AND we dont have a session here.. redirect to login page.
                HttpCookie authenticationCookie = Request.Cookies[FormsAuthentication.FormsCookieName];
                if (authenticationCookie != null)
                {
                    FormsAuthenticationTicket authenticationTicket = FormsAuthentication.Decrypt(authenticationCookie.Value);
                    if (authenticationTicket != null && !authenticationTicket.Expired)
                    {
                        if (Session["username"] == null)
                        {
                            //This means for some reason the session expired before the authentication ticket. Force a login.
                            FormsAuthentication.SignOut();
                            Response.Redirect(FormsAuthentication.LoginUrl, true);
                            return;
                        }
                    }
                }
            }
        }