using System;

using System.Web.Mvc;

using System.Collections.Generic;

using System.Web.Http;

using System.Web;

using System.Web.Routing;

​

namespace HelloWorldMvcApp

{

    [MyActionFilter]

    public class HomeController : Controller

    {

        public ActionResult Index()

        {

            return View(new SampleViewModel() { SomeValue = "Index" });

        }

​

        [AllowAnonymous]

        public ActionResult NotAuthorized()

        {

            return View(new SampleViewModel() { SomeValue = "NotAuthorized" });

        }

    }

​

    public class MyActionFilter : ActionFilterAttribute

    {

        public override void OnActionExecuting(ActionExecutingContext filterContext)

        {

            if (filterContext.HasAttribute(typeof(AllowAnonymousAttribute)))

            {

                return;

            }

            filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary

            {

                { "controller", "Home" }, 

                { "action", "NotAuthorized" }

            });

            base.OnActionExecuting(filterContext);

        }

    }

    public static class MyExtensionMethods

    {

        public static bool HasAttribute(this ActionExecutingContext filterContext, Type attribute)

        {

            var actionDesc = filterContext.ActionDescriptor;

            var controllerDesc = actionDesc.ControllerDescriptor;

            bool allowAnon = 

                actionDesc.IsDefined(attribute, true) ||

                controllerDesc.IsDefined(attribute, true);

            return allowAnon;

        }

    }

}