set current user in asp.net mvc

Question

I'm not sure if this is the best way to do it, but I want to keep a user object alive during all requests of the current user. From reading several resources I learned that you should create your own IPrinciple which holds this. But I don't want to trigger the database every authentication request. Any recommendations on how to handle this? Is caching the db request a good idea?

 protected void Application_AuthenticateRequest(Object sender, EventArgs e)
    {
        HttpCookie authCookie = Request.Cookies[FormsAuthentication.FormsCookieName];
        if (authCookie != null)
        {
            FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);

            User user;
            using (HgDataContext hg = new HgDataContext())
            {
                if (Session["user"] != null)
                {
                   user = (from u in hg.Users where u.EmailAddress == authTicket.Name select u).Single();
                } else
                {
                   user = Session["user"] as User;
                } 
            }
            var principal = new HgPrincipal(user);
            Context.User = principal;
        }
    }

Answer 1

Session is probably the appropriate way to do this, and in fact is one of the few uses of Session that I'd advocate.

Answer 2

I'm now using the following code which caches the user, take care that you remove the cache after an update!

 protected void Application_AuthenticateRequest(Object sender, EventArgs e)
        {
            HttpCookie authCookie = Request.Cookies[FormsAuthentication.FormsCookieName];
            if (authCookie != null)
            {
                FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);

                User user;
                Cache cache = HttpContext.Current.Cache;
                using (HgDataContext hg = new HgDataContext())
                {
                    user =  cache[authTicket.Name] as User;
                    if (user == null)
                    {
                       user = (from u in hg.Users where u.EmailAddress == authTicket.Name select u).Single();
                       cache[authTicket.Name] = user;
                    }
                }
                var principal = new HgPrincipal(user);
                Context.User = principal;
            }
        }