ASP.NET MVC Action Filter for automatic handling of Ajax requests

gistfile1.cs

using System.Net;
using System.Web.Mvc;

namespace Fabrik.Common.Web
{
    public class HijaxAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            if (CanBeHijaxed(filterContext))
            {
                var modelState = filterContext.Controller.ViewData.ModelState;
                if (!modelState.IsValid)
                {
                    filterContext.Result = new JsonStatusCodeResult(modelState.ToSerializableDictionary(), HttpStatusCode.BadRequest);
                }
            }
        }

        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            if (CanBeHijaxed(filterContext))
            {
                var modelState = filterContext.Controller.ViewData.ModelState;
                if (!modelState.IsValid)
                {
                    filterContext.Result = new JsonStatusCodeResult(modelState.ToSerializableDictionary(), HttpStatusCode.BadRequest);
                }
                else
                {
                    var result = filterContext.Result as RedirectResult;

                    if (result != null)
                    {
                        var redirectUrl = UrlHelper.GenerateContentUrl(result.Url, filterContext.HttpContext);
                        filterContext.Result = new JavaScriptRedirectResult(redirectUrl);
                    }
                    else // just return an empty result - could maybe convert view model etc.
                    {
                        filterContext.Result = new EmptyResult();
                    }
                }
            }
        }

        private bool CanBeHijaxed(ControllerContext controllerContext)
        {
            var request = controllerContext.RequestContext.HttpContext.Request;
            return request.IsAjaxRequest() && request.HttpMethod == "POST";
        }
    }
}