/Src/Commons.Web.Mvc/Attributes/AjaxControllerAttribute.cs

using System;

using System.Linq;

using System.Web.Mvc;

using System.Web;

using System.Web.Routing;

using BoC.Web.Mvc.ActionResults;



namespace BoC.Web.Mvc.Attributes

{

    /// <summary>

    /// The AjaxControllerAttribute does a few things

    ///     - if the current request is a json-request, it returns the model as a json result

    ///     - if the current request is an xml-request, it returns the model as an xml result

    ///     - if the current request is an ajax-request, it returns a partialviewresult

    /// If your controller uses this attribute, you can always return a normal ViewResult, it will be transformed by this actionfilter

    /// </summary>

    public class AjaxControllerAttribute: ActionFilterAttribute

    {

        public override void OnActionExecuted(ActionExecutedContext filterContext)

        {

            base.OnActionExecuted(filterContext);

            

            var responseType = filterContext.HttpContext.Request.GetPreferedResponseType();



            if (filterContext.HttpContext.Request.IsJqAjaxRequest() 

                && filterContext.Exception == null

                && ((filterContext.Result is RedirectToRouteResult) || filterContext.Result is RedirectResult))

            {

                //If we have redirect result, and it is an ajax request:

                // - IF it is json or xml:

                // we'll return 200 OK with the URL in the header, the user can decide if he wants to redirect

                // - if it is an html request, we'll redirect to the new action but send info about the ajax-request with it

                

                var redir = filterContext.Result as RedirectToRouteResult;

                if (responseType == ResponseType.Json || responseType == ResponseType.Xml) //we'll return a redirect object

                {

                    string url;

                    if (redir != null)

                    {

                        url = UrlHelper.GenerateUrl(

                            redir.RouteName,

                            null /* actionName */,

                            null /* controllerName */,

                            redir.RouteValues, 

                            RouteTable.Routes, 

                            filterContext.RequestContext,

                            false /* includeImplicitMvcValues */);

                    }

                    else

                    {

                        url = ((RedirectResult) filterContext.Result).Url;

                    }

                    filterContext.RequestContext.HttpContext.Response.AddHeader("Location", url);

                }

                else if (redir != null && !redir.RouteValues.ContainsKey("__mvcajax")) //without these extra params we can't detect an ajax request in FireFox :(

                {

                    redir.RouteValues["__mvcajax"] = "true";

                    redir.RouteValues["resultformat"] = filterContext.RouteData.Values["resultformat"] ??

                                                        filterContext.RouteData.DataTokens["resultformat"];

                    redir.RouteValues["format"] = filterContext.RouteData.Values["format"];

                    return;

                }



            }

            

            if (filterContext.IsChildAction || filterContext.HttpContext.Request.IsJqAjaxRequest())

            {

                var result = filterContext.Result as ViewResult;

                if (result != null && responseType == ResponseType.Html)

                {

                    var viewResult = filterContext.Result as ViewResult;

                    //prefer partial

                    if (viewResult != null)

                    {

                        filterContext.Result = new PartialViewResult()

                                                   {

                                                       TempData = viewResult.TempData,

                                                       ViewData = viewResult.ViewData,

                                                       ViewName = viewResult.ViewName,

                                                   };

                    }

                }

                else if (responseType == ResponseType.Json || responseType == ResponseType.Xml)

                {

                    ViewDataDictionary data = filterContext.Result is ViewResultBase ? ((ViewResultBase)filterContext.Result).ViewData : filterContext.Controller.ViewData;

					

                    object model = data;

                    if (filterContext.Exception != null)

                        model = filterContext.Exception;

                    else if (data != null && data.Model != null)

                        model = data.Model;



                    if (model is Exception)

                    {

                        filterContext.Result = null;



                        Exception exc = ((Exception)model).InnerException ?? ((Exception)model);

                        if (exc is HttpException)

                        {

                            filterContext.HttpContext.Response.StatusCode = ((HttpException)exc).GetHttpCode();

                        }

                        else

                        {

                            filterContext.HttpContext.Response.StatusCode = 500;

                        }

                        filterContext.HttpContext.Response.StatusDescription = exc.Message;

                        filterContext.ExceptionHandled = true;

                        model = new SimpleException(exc);

                    }



                    if (responseType == ResponseType.Json)

                    {

                        //see if custom JsonRequestBehavior has been set

                        var attrib = filterContext.ActionDescriptor.GetCustomAttributes(typeof (JsonRequestBehaviorAttribute), true).OfType<JsonRequestBehaviorAttribute>().FirstOrDefault();

                        if (attrib == null)

                        {

                            attrib = filterContext.ActionDescriptor.ControllerDescriptor.GetCustomAttributes(typeof (JsonRequestBehaviorAttribute), true).OfType<JsonRequestBehaviorAttribute>().FirstOrDefault();

                        }



                        if (!(filterContext.Result is JsonResult))

                        {

                            filterContext.Result = new JsonResult()

                                                       {

                                                           Data = model ?? new object(),

                                                           JsonRequestBehavior = (attrib == null) ? JsonRequestBehavior.DenyGet : attrib.JsonRequestBehavior

                                                       };

                        } 

                        else if (attrib != null)

                        {

                            (filterContext.Result as JsonResult).JsonRequestBehavior = attrib.JsonRequestBehavior;

                        }

                    }

                    else if (!(filterContext.Result is XmlResult))

                    {

                        filterContext.Result = new XmlResult(model);

                    }

                }

            }

        }



        /* In asp.net mvc 2, the OnActionExecuted seems to be triggered always, so we don't need this seperate function anymore 

        void IExceptionFilter.OnException(ExceptionContext filterContext)

        {

            if (filterContext.Result == null && filterContext.HttpContext.Request.GetPreferedResponseType() == ResponseType.Json)

            {

                filterContext.Result = new JsonResult()

                {

                    Data = new {errors = new SimpleException[] {new SimpleException(filterContext.Exception)}}

                };

                filterContext.HttpContext.Response.Clear();

                filterContext.ExceptionHandled = true;

                if (filterContext.Exception is HttpException)

                {

                    filterContext.HttpContext.Response.StatusCode = ((HttpException)filterContext.Exception).GetHttpCode();

                }

                else

                {

                    filterContext.HttpContext.Response.StatusCode = 500;

                }

                filterContext.HttpContext.Response.StatusDescription = filterContext.Exception.Message;

            }

        }

        */

    }

}