How can I properly handle 404 in ASP NET MVC

Question

I am using RC2  Using URL Routing    routes MapRoute       Error           url         new   controller    Errors   action    NotFound        404s      The above seems to take care of requests like this  assuming default route tables setup by initial MVC project     blah blah blah blah   Overriding HandleUnknownAction   in the controller itself      404s - handle here  bad action requested protected override void HandleUnknownAction string actionName        ViewData  actionName     actionName      View  NotFound   ExecuteResult this ControllerContext         However the previous strategies do not handle a request to a Bad Unknown controller   For example  I do not have a   IDoNotExist   if I request this I get the generic 404 page from the web server and not my 404 if I use routing   override     So finally  my question is   Is there any way to catch this type of request using a route or something else in the MVC framework itself     OR should I just default to using Web Config customErrors as my 404 handler and forget all this   I assume if I go with customErrors I ll have to store the generic 404 page outside of  Views due to the Web Config restrictions on direct access

User · Answer

My shortened solution that works with unhandled areas, controllers and actions:

Create a view 404.cshtml.

Create a base class for your controllers:

public class Controller : System.Web.Mvc.Controller
{
    protected override void HandleUnknownAction(string actionName)
    {
        Http404().ExecuteResult(ControllerContext);
    }

    protected virtual ViewResult Http404()
    {
        Response.StatusCode = (int)HttpStatusCode.NotFound;
        return View("404");
    }
}

Create a custom controller factory returning your base controller as a fallback:

public class ControllerFactory : DefaultControllerFactory
{
    protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        if (controllerType != null)
            return base.GetControllerInstance(requestContext, controllerType);

        return new Controller();
    }
}

Add to Application_Start() the following line:

ControllerBuilder.Current.SetControllerFactory(typeof(ControllerFactory));

User · Answer

I have gone through all articles but nothing works for me  My requirement user type anything in your url custom 404 page should show I thought it is very straight forward But you should understand handling of 404 properly     lt system web gt       lt customErrors mode  On  redirectMode  ResponseRewrite  gt         lt error statusCode  404  redirect    PageNotFound aspx   gt       lt  customErrors gt     lt  system web gt   lt system webServer gt       lt httpErrors errorMode  Custom  gt         lt remove statusCode  404   gt         lt error statusCode  404  path   PageNotFound html  responseMode  ExecuteURL   gt       lt  httpErrors gt   lt  system webServer gt    I found this article very helpfull should be read at once Custome error page-Ben Foster

User · Answer

Here is another method using MVC tools which you can handle requests to bad controller names  bad route names  and any other criteria you see fit inside of an Action method   Personally  I prefer to avoid as many web config settings as possible  because they do the 302   200 redirect and do not support ResponseRewrite  Server Transfer  using Razor views   I d prefer to return a 404 with a custom error page for SEO reasons   Some of this is new take on cottsak s technique above   This solution also uses minimal web config settings favoring the MVC 3 Error Filters instead   Usage  Just throw a HttpException from an action or custom ActionFilterAttribute   Throw New HttpException HttpStatusCode NotFound    Custom Exception Message Here      Step 1  Add the following setting to your web config   This is required to use MVC s HandleErrorAttribute     lt customErrors mode  On  redirectMode  ResponseRedirect    gt    Step 2  Add a custom HandleHttpErrorAttribute similar to the MVC framework s HandleErrorAttribute  except for HTTP errors    lt AttributeUsage AttributeTargets All  AllowMultiple  True  gt  Public Class HandleHttpErrorAttribute     Inherits FilterAttribute     Implements IExceptionFilter      Private Const m DefaultViewFormat As String    ErrorHttp 0        Private m HttpCode As HttpStatusCode     Private m Master As String     Private m View As String      Public Property HttpCode As HttpStatusCode         Get             If m HttpCode   0 Then                 Return HttpStatusCode NotFound             End If             Return m HttpCode         End Get         Set value As HttpStatusCode              m HttpCode   value         End Set     End Property      Public Property Master As String         Get             Return If m Master  String Empty          End Get         Set value As String              m Master   value         End Set     End Property      Public Property View As String         Get             If String IsNullOrEmpty m View  Then                 Return String Format m DefaultViewFormat  Me HttpCode              End If             Return m View         End Get         Set value As String              m View   value         End Set     End Property      Public Sub OnException filterContext As System Web Mvc ExceptionContext  Implements System Web Mvc IExceptionFilter OnException         If filterContext Is Nothing Then Throw New ArgumentException  filterContext            If filterContext IsChildAction Then             Return         End If          If filterContext ExceptionHandled OrElse Not filterContext HttpContext IsCustomErrorEnabled Then             Return         End If          Dim ex As HttpException   TryCast filterContext Exception  HttpException          If ex Is Nothing OrElse ex GetHttpCode   HttpStatusCode InternalServerError Then             Return         End If          If ex GetHttpCode  lt  gt  Me HttpCode Then             Return         End If          Dim controllerName As String   filterContext RouteData Values  controller           Dim actionName As String   filterContext RouteData Values  action           Dim model As New HandleErrorInfo filterContext Exception  controllerName  actionName           filterContext Result   New ViewResult With                ViewName   Me View               MasterName   Me Master               ViewData   New ViewDataDictionary Of HandleErrorInfo  model                TempData   filterContext Controller TempData                   filterContext ExceptionHandled   True         filterContext HttpContext Response Clear           filterContext HttpContext Response StatusCode   Me HttpCode         filterContext HttpContext Response TrySkipIisCustomErrors   True     End Sub End Class   Step 3  Add Filters to the GlobalFilterCollection  GlobalFilters Filters  in Global asax   This example will route all InternalServerError  500  errors to the Error shared view  Views Shared Error vbhtml    NotFound  404  errors will be sent to ErrorHttp404 vbhtml in the shared views as well   I ve added a 401 error here to show you how this can be extended for additional HTTP error codes   Note that these must be shared views  and they all use the System Web Mvc HandleErrorInfo object as a the model   filters Add New HandleHttpErrorAttribute With   View    ErrorHttp401    HttpCode   HttpStatusCode Unauthorized   filters Add New HandleHttpErrorAttribute With   View    ErrorHttp404    HttpCode   HttpStatusCode NotFound   filters Add New HandleErrorAttribute With   View    Error      Step 4  Create a base controller class and inherit from it in your controllers   This step allows us to handle unknown action names and raise the HTTP 404 error to our HandleHttpErrorAttribute   Public Class BaseController     Inherits System Web Mvc Controller      Protected Overrides Sub HandleUnknownAction actionName As String          Me ActionInvoker InvokeAction Me ControllerContext   Unknown       End Sub      Public Function Unknown   As ActionResult         Throw New HttpException HttpStatusCode NotFound   The specified controller or action does not exist            Return New EmptyResult     End Function End Class   Step 5  Create a ControllerFactory override  and override it in your Global asax file in Application Start   This step allows us to raise the HTTP 404 exception when an invalid controller name has been specified   Public Class MyControllerFactory     Inherits DefaultControllerFactory      Protected Overrides Function GetControllerInstance requestContext As System Web Routing RequestContext  controllerType As System Type  As System Web Mvc IController         Try             Return MyBase GetControllerInstance requestContext  controllerType          Catch ex As HttpException             Return DependencyResolver Current GetService Of BaseController            End Try     End Function End Class   In Global asax vb Application Start   controllerBuilder Current SetControllerFactory New MyControllerFactory    Step 6  Include a special route in your RoutTable Routes for the BaseController Unknown action   This will help us raise a 404 in the case where a user accesses an unknown controller  or unknown action    BaseController routes MapRoute         Unknown    BaseController  action   id          New With   controller    BaseController    action    Unknown    id   UrlParameter Optional        Summary  This example demonstrated how one can use the MVC framework to return 404 Http Error Codes to the browser without a redirect using filter attributes and shared error views   It also demonstrates showing the same custom error page when invalid controller names and action names are specified   I ll add a screenshot of an invalid controller name  action name  and a custom 404 raised from the Home TriggerNotFound action if I get enough votes to post one      Fiddler returns a 404 message when I access the following URLs using this solution      InvalidController  Home InvalidRoute  InvalidController InvalidRoute  Home TriggerNotFound   cottsak s post above and these articles were good references      Problems using CustomErrors redirectMode ResponseRewrite Elmah   MVC HandleErrorAttribute

User · Answer

I really like cottsaks solution and think its very clearly explained  my only addition was to alter step 2 as follows  public abstract class MyController   Controller         region Http404 handling      protected override void HandleUnknownAction string actionName                  if controller is ErrorController dont  nest  exceptions         if this GetType      typeof ErrorController           this InvokeHttp404 HttpContext              public ActionResult InvokeHttp404 HttpContextBase httpContext                IController errorController   ObjectFactory GetInstance lt ErrorController gt             var errorRoute   new RouteData            errorRoute Values Add  controller    Error            errorRoute Values Add  action    Http404            errorRoute Values Add  url   httpContext Request Url OriginalString           errorController Execute new RequestContext               httpContext  errorRoute             return new EmptyResult                endregion     Basically this stops urls containing invalid actions AND controllers from triggering the exception routine twice  eg for urls such as asdfsdf dfgdfgd

User · Answer

Try NotFoundMVC on nuget  It works   no setup

User · Answer

ASP NET MVC doesn t support custom 404 pages very well  Custom controller factory  catch-all route  base controller class with HandleUnknownAction - argh   IIS custom error pages are better alternative so far   web config   lt system webServer gt     lt httpErrors errorMode  Custom  existingResponse  Replace  gt       lt remove statusCode  404    gt       lt error statusCode  404  responseMode  ExecuteURL  path   Error PageNotFound    gt     lt  httpErrors gt   lt  system webServer gt    ErrorController  public class ErrorController   Controller       public ActionResult PageNotFound                 Response StatusCode   404          return View              Sample Project   Test404 on GitHub Live website

User · Answer

My solution  in case someone finds it useful   In Web config    lt system web gt       lt customErrors mode  On  defaultRedirect  Error   gt         lt error statusCode  404  redirect    Error PageNotFound   gt       lt  customErrors gt           lt  system web gt    In Controllers ErrorController cs   public class ErrorController   Controller       public ActionResult PageNotFound                 if Request IsAjaxRequest                  Response StatusCode    int HttpStatusCode NotFound              return Content  Not Found    text plain                       return View              Add a PageNotFound cshtml in the Shared folder  and that s it

User · Answer

Quick Answer   TL DR  For the lazy people out there  Install-Package MagicalUnicornMvcErrorToolkit -Version 1 0  Then remove this line from global asax GlobalFilters Filters Add new HandleErrorAttribute      And this is only for IIS7  and IIS Express  If you re using Cassini    well    um    er   awkward       Long  explained answer I know this has been answered  But the answer is REALLY SIMPLE  cheers to David Fowler and Damian Edwards for really answering this   There is no need to do anything custom  For ASP NET MVC3  all the bits and pieces are there  Step 1 - gt  Update your web config in TWO spots   lt system web gt       lt customErrors mode  quot On quot  defaultRedirect  quot  ServerError quot  gt         lt error statusCode  quot 404 quot  redirect  quot  NotFound quot    gt       lt  customErrors gt   and  lt system webServer gt       lt httpErrors errorMode  quot Custom quot  gt         lt remove statusCode  quot 404 quot  subStatusCode  quot -1 quot    gt         lt error statusCode  quot 404 quot  path  quot  NotFound quot  responseMode  quot ExecuteURL quot    gt         lt remove statusCode  quot 500 quot  subStatusCode  quot -1 quot    gt         lt error statusCode  quot 500 quot  path  quot  ServerError quot  responseMode  quot ExecuteURL quot    gt       lt  httpErrors gt            lt system webServer gt       lt  system web gt   Now take careful note of the ROUTES I ve decided to use  You can use anything  but my routes are   NotFound  lt - for a 404 not found  error page   ServerError  lt - for any other error  include errors that happen in my code  this is a 500 Internal Server Error  See how the first section in  lt system web gt  only has one custom entry  The statusCode  quot 404 quot  entry  I ve only listed one status code because all other errors  including the 500 Server Error  ie  those pesky error that happens when your code has a bug and crashes the user s request     all the other errors are handled by the setting defaultRedirect  quot  ServerError quot     which says  if you are not a 404 page not found  then please goto the route  ServerError  Ok  that s out of the way   now to my routes listed in global asax Step 2 - Creating the routes in Global asax Here s my full route section   public static void RegisterRoutes RouteCollection routes        routes IgnoreRoute  quot  resource  axd   pathInfo  quot        routes IgnoreRoute  quot   favicon  quot   new  favicon     quot       favicon ico       quot          routes MapRoute           quot Error - 404 quot            quot NotFound quot           new   controller    quot Error quot   action    quot NotFound quot                    routes MapRoute           quot Error - 500 quot            quot ServerError quot           new   controller    quot Error quot   action    quot ServerError quot                   routes MapRoute           quot Default quot      Route name          quot  controller   action   id  quot      URL with parameters         new  controller    quot Home quot   action    quot Index quot   id   UrlParameter Optional                That lists two ignore routes - gt  axd s and favicons  ooo  bonus ignore route  for you   Then  and the order is IMPERATIVE HERE   I have my two explicit error handling routes    followed by any other routes  In this case  the default one  Of course  I have more  but that s special to my web site  Just make sure the error routes are at the top of the list  Order is imperative  Finally  while we are inside our global asax file  we do NOT globally register the HandleError attribute  No  no  no sir  Nadda  Nope  Nien  Negative  Noooooooooo    Remove this line from global asax GlobalFilters Filters Add new HandleErrorAttribute      Step 3 - Create the controller with the action methods Now    we add a controller with two action methods     public class ErrorController   Controller       public ActionResult NotFound                 Response StatusCode    int HttpStatusCode NotFound          return View               public ActionResult ServerError                 Response StatusCode    int HttpStatusCode InternalServerError              Todo  Pass the exception into the view model  which you can make                   That s an exercise  dear reader  for -you-                   In case u want to pass it to the view  if you re admin  etc             if  User IsAdmin      lt -- I just made that up    U get the idea                                var exception   Server GetLastError                      etc                         return View                  Shhh    secret test method    ooOOooOooOOOooohhhhhhhh     public ActionResult ThrowError                 throw new NotImplementedException  quot Pew   Pew quot             Ok  lets check this out  First of all  there is NO  HandleError  attribute here  Why  Because the built in ASP NET framework is already handling errors AND we have specified all the shit we need to do to handle an error    It s in this method  Next  I have the two action methods  Nothing tough there  If u wish to show any exception info  then u can use Server GetLastError   to get that info  Bonus WTF  Yes  I made a third action method  to test error handling  Step 4 - Create the Views And finally  create two views  Put em in the normal view spot  for this controller   Bonus comments  You don t need an Application Error object sender  EventArgs e  The above steps all work 100  perfectly with Elmah  Elmah fraking wroxs   And that  my friends  should be it  Now  congrats for reading this much and have a Unicorn as a prize

User · Answer

The code is taken from http   blogs microsoft co il blogs shay archive 2009 03 06 real-world-error-hadnling-in-asp-net-mvc-rc2 aspx and works in ASP net MVC 1 0 as well   Here s how I handle http exceptions   protected void Application Error object sender  EventArgs e       Exception exception   Server GetLastError          Log the exception      ILogger logger   Container Resolve lt ILogger gt        logger Error exception       Response Clear        HttpException httpException   exception as HttpException      RouteData routeData   new RouteData       routeData Values Add  controller    Error        if  httpException    null              routeData Values Add  action    Index            else   It s an Http Exception  Let s handle it              switch  httpException GetHttpCode                       case 404                   Page not found                routeData Values Add  action    HttpError404                  break            case 500                   Server error                routeData Values Add  action    HttpError500                  break                 Here you can handle Views to other error codes                I choose a General error template              default                routeData Values Add  action    General                  break                               Pass exception details to the target error View    routeData Values Add  error   exception         Clear the error on server    Server ClearError          Avoid IIS7 getting in the middle   Response TrySkipIisCustomErrors   true         Call target Controller and pass the routeData    IController errorController   new ErrorController      errorController Execute new RequestContext             new HttpContextWrapper Context   routeData

User · Answer

Requirements for 404  The following are my requirements for a 404 solution and below i show how i implement it    I want to handle matched routes with bad actions I want to handle matched routes with bad controllers I want to handle un-matched routes  arbitrary urls that my app can t understand  - i don t want these bubbling up to the Global asax or IIS because then i can t redirect back into my MVC app properly I want a way to handle in the same manner as above  custom 404s - like when an ID is submitted for an object that does not exist  maybe deleted  I want all my 404s to return an MVC view  not a static page  to which i can pump more data later if necessary  good 404 designs  and they must return the HTTP 404 status code   Solution  I think you should save Application Error in the Global asax for higher things  like unhandled exceptions and logging  like Shay Jacoby s answer shows  but not 404 handling  This is why my suggestion keeps the 404 stuff out of the Global asax file   Step 1  Have a common place for 404-error logic  This is a good idea for maintainability  Use an ErrorController so that future improvements to your well designed 404 page can adapt easily  Also  make sure your response has the 404 code   public class ErrorController   MyController        region Http404      public ActionResult Http404 string url                Response StatusCode    int HttpStatusCode NotFound          var model   new NotFoundViewModel               If the url is relative   NotFound  route  then replace with Requested path         model RequestedUrl   Request Url OriginalString Contains url   amp  Request Url OriginalString    url               Request Url OriginalString   url             Dont get the user stuck in a  retry loop  by            allowing the Referrer to be the same as the Request         model ReferrerUrl   Request UrlReferrer    null  amp  amp              Request UrlReferrer OriginalString    model RequestedUrl               Request UrlReferrer OriginalString   null              TODO  insert ILogger here          return View  NotFound   model             public class NotFoundViewModel               public string RequestedUrl   get  set            public string ReferrerUrl   get  set                endregion     Step 2  Use a base Controller class so you can easily invoke your custom 404 action and wire up HandleUnknownAction  404s in ASP NET MVC need to be caught at a number of places  The first is HandleUnknownAction   The InvokeHttp404 method creates a common place for re-routing to the ErrorController and our new Http404 action  Think DRY   public abstract class MyController   Controller        region Http404 handling      protected override void HandleUnknownAction string actionName                   If controller is ErrorController dont  nest  exceptions         if  this GetType      typeof ErrorController               this InvokeHttp404 HttpContext              public ActionResult InvokeHttp404 HttpContextBase httpContext                IController errorController   ObjectFactory GetInstance lt ErrorController gt             var errorRoute   new RouteData            errorRoute Values Add  controller    Error            errorRoute Values Add  action    Http404            errorRoute Values Add  url   httpContext Request Url OriginalString           errorController Execute new RequestContext               httpContext  errorRoute             return new EmptyResult                endregion     Step 3  Use Dependency Injection in your Controller Factory and wire up 404 HttpExceptions  Like so  it doesn t have to be StructureMap    MVC1 0 example   public class StructureMapControllerFactory   DefaultControllerFactory       protected override IController GetControllerInstance Type controllerType                try                       if  controllerType    null                  return base GetControllerInstance controllerType                     catch  HttpException ex                        if  ex GetHttpCode       int HttpStatusCode NotFound                                IController errorController   ObjectFactory GetInstance lt ErrorController gt                       ErrorController errorController  InvokeHttp404 RequestContext HttpContext                    return errorController                            else                 throw ex                     return ObjectFactory GetInstance controllerType  as Controller            MVC2 0 example       protected override IController GetControllerInstance RequestContext requestContext  Type controllerType                try                       if  controllerType    null                  return base GetControllerInstance requestContext  controllerType                     catch  HttpException ex                        if  ex GetHttpCode      404                                IController errorController   ObjectFactory GetInstance lt ErrorController gt                       ErrorController errorController  InvokeHttp404 requestContext HttpContext                    return errorController                            else                 throw ex                     return ObjectFactory GetInstance controllerType  as Controller          I think its better to catch errors closer to where they originate  This is why i prefer the above to the Application Error handler   This is the second place to catch 404s   Step 4  Add a NotFound route to Global asax for urls that fail to be parsed into your app  This route should point to our Http404 action  Notice the url param will be a relative url because the routing engine is stripping the domain part here  That is why we have all that conditional url logic in Step 1           routes MapRoute  NotFound      url                 new   controller    Error   action    Http404        This is the third and final place to catch 404s in an MVC app that you don t invoke yourself  If you don t catch unmatched routes here then MVC will pass the problem up to ASP NET  Global asax  and you don t really want that in this situation   Step 5  Finally  invoke 404s when your app can t find something  Like when a bad ID is submitted to my Loans controller  derives from MyController                  GET   Detail ID      public ActionResult Detail int ID                Loan loan   this  svc GetLoans   WithID ID           if  loan    null              return this InvokeHttp404 HttpContext           else             return View loan           It would be nice if all this could be hooked up in fewer places with less code but i think this solution is more maintainable  more testable and fairly pragmatic     Thanks for the feedback so far  I d love to get more   NOTE  This has been edited significantly from my original answer but the purpose requirements are the same - this is why i have not added a new answer

User · Answer

Adding my solution  which is almost identical to Herman Kan s  with a small wrinkle to allow it to work for my project   Create a custom error controller   public class Error404Controller   BaseController        HttpGet      public ActionResult PageNotFound                 Response StatusCode   404          return View  404              Then create a custom controller factory   public class CustomControllerFactory   DefaultControllerFactory       protected override IController GetControllerInstance RequestContext requestContext  Type controllerType                return controllerType    null   new Error404Controller     base GetControllerInstance requestContext  controllerType             Finally  add an override to the custom error controller   protected override void HandleUnknownAction string actionName        var errorRoute   new RouteData        errorRoute Values Add  controller    Error404        errorRoute Values Add  action    PageNotFound        new Error404Controller   Execute new RequestContext HttpContext  errorRoute        And that s it  No need for Web config changes

User · Answer

1  Make abstract Controller class    public abstract class MyController Controller       public ActionResult NotFound                 Response StatusCode   404          return View  NotFound               protected override void HandleUnknownAction string actionName                this ActionInvoker InvokeAction this ControllerContext   NotFound              protected override void OnAuthorization AuthorizationContext filterContext            2  Make inheritence from this abstract class in your all controllers    public class HomeController   MyController        3  And add a view named  NotFound  in you View-Shared folder

User · Answer

It seems to me that the standard CustomErrors configuration should just work however  due to the reliance on Server Transfer it seems that the internal implementation of ResponseRewrite isn t compatible with MVC   This feels like a glaring functionality hole to me  so I decided to re-implement this feature using a HTTP module  The solution below allows you to handle any HTTP status code  including 404  by redirecting to any valid MVC route just as you would do normally    lt customErrors mode  RemoteOnly  redirectMode  ResponseRewrite  gt       lt error statusCode  404  redirect  404 aspx    gt       lt error statusCode  500  redirect    MVCErrorPage    gt   lt  customErrors gt    This has been tested on the following platforms    MVC4 in Integrated Pipeline Mode  IIS Express 8  MVC4 in Classic Mode  VS Development Server  Cassini  MVC4 in Classic Mode  IIS6    Benefits   Generic solution which can be dropped into any MVC project Enables support for traditional custom errors configuration Works in both Integrated Pipeline and Classic modes     The Solution  namespace Foo Bar Modules             lt summary gt          Enables support for CustomErrors ResponseRewrite mode in MVC           lt  summary gt      public class ErrorHandler   IHttpModule            private HttpContext HttpContext   get   return HttpContext Current              private CustomErrorsSection CustomErrors   get  set             public void Init HttpApplication application                System Configuration Configuration configuration   WebConfigurationManager OpenWebConfiguration                   CustomErrors    CustomErrorsSection configuration GetSection  system web customErrors                 application EndRequest    Application EndRequest                     protected void Application EndRequest object sender  EventArgs e                    only handle rewrite mode  ignore redirect configuration  if it ain t broke don t re-implement it              if  CustomErrors RedirectMode    CustomErrorsRedirectMode ResponseRewrite  amp  amp  HttpContext IsCustomErrorEnabled                     int statusCode   HttpContext Response StatusCode                      if this request has thrown an exception then find the real status code                 Exception exception   HttpContext Error                  if  exception    null                           set default error status code for application exceptions                     statusCode    int HttpStatusCode InternalServerError                                     HttpException httpException   exception as HttpException                  if  httpException    null                        statusCode   httpException GetHttpCode                                       if   HttpStatusCode statusCode    HttpStatusCode OK                         Dictionary lt int  string gt  errorPaths   new Dictionary lt int  string gt                          foreach  CustomError error in CustomErrors Errors                            errorPaths Add error StatusCode  error Redirect                                                 find a custom error path for this status code                     if  errorPaths Keys Contains statusCode                             string url   errorPaths statusCode                               avoid circular redirects                         if   HttpContext Request Url AbsolutePath Equals VirtualPathUtility ToAbsolute url                                   HttpContext Response Clear                                HttpContext Response TrySkipIisCustomErrors   true                               HttpContext Server ClearError                                    do the redirect here                             if  HttpRuntime UsingIntegratedPipeline                                    HttpContext Server TransferRequest url  true                                                             else                                   HttpContext RewritePath url  false                                    IHttpHandler httpHandler   new MvcHttpHandler                                    httpHandler ProcessRequest HttpContext                                                                 return the original status code to the client                                 this won t work in integrated pipleline mode                              HttpContext Response StatusCode   statusCode                                                                                                         public void Dispose                             Usage  Include this as the final HTTP module in your web config     lt system web gt       lt httpModules gt         lt add name  ErrorHandler  type  Foo Bar Modules ErrorHandler    gt       lt  httpModules gt     lt  system web gt      lt  -- IIS7  -- gt     lt system webServer gt       lt modules gt         lt add name  ErrorHandler  type  Foo Bar Modules ErrorHandler    gt       lt  modules gt     lt  system webServer gt      For those of you paying attention you will notice that in Integrated Pipeline mode this will always respond with HTTP 200 due to the way Server TransferRequest works  To return the proper error code I use the following error controller   public class ErrorController   Controller        public ErrorController            public ActionResult Index int id               pass real error code to client         HttpContext Response StatusCode   id          HttpContext Response TrySkipIisCustomErrors   true           return View  Errors     id ToString

User · Answer

I ve investigated A LOT on how to properly manage 404s in MVC  specifically MVC3   and this  IMHO is the best solution I ve come up with   In global asax   public class MvcApplication   HttpApplication       protected void Application EndRequest                 if  Context Response StatusCode    404                        Response Clear                 var rd   new RouteData                rd DataTokens  area      AreaName      In case controller is in another area             rd Values  controller      Errors               rd Values  action      NotFound                IController c   new ErrorsController                c Execute new RequestContext new HttpContextWrapper Context   rd                        ErrorsController   public sealed class ErrorsController   Controller       public ActionResult NotFound                 ActionResult result           object model   Request Url PathAndQuery           if   Request IsAjaxRequest                result   View model           else             result   PartialView   NotFound   model            return result             Optional   Explanation   AFAIK  there are 6 different cases that an ASP NET MVC3 apps can generate 404s    Automatically generated by ASP NET Framework     1  An URL does not find a match in the route table    Automatically generated by ASP NET MVC Framework     2  An URL finds a match in the route table  but specifies a non-existent controller    3  An URL finds a match in the route table  but specifies a non-existant action    Manually generated     4  An action returns an HttpNotFoundResult by using the method HttpNotFound      5  An action throws an HttpException with the status code 404    6  An actions manually modifies the Response StatusCode property to 404   Normally  you want to accomplish 3 objectives    1  Show a custom 404 error page to the user    2  Maintain the 404 status code on the client response  specially important for SEO     3  Send the response directly  without involving a 302 redirection   There are various ways to try to accomplish this    1    lt system web gt       lt customErrors mode  On  gt           lt error statusCode  404  redirect    Errors NotFound   gt       lt  customError gt   lt  system web gt    Problems with this solution    Does not comply with objective  1  in cases  1    4    6   Does not comply with objective  2  automatically  It must be programmed manually  Does not comply with objective  3      2    lt system webServer gt       lt httpErrors errorMode  Custom  gt           lt remove statusCode  404   gt           lt error statusCode  404  path  App Errors NotFound  responseMode  ExecuteURL   gt       lt  httpErrors gt   lt  system webServer gt    Problems with this solution    Only works on IIS 7   Does not comply with objective  1  in cases  2    3    5   Does not comply with objective  2  automatically  It must be programmed manually     3    lt system webServer gt       lt httpErrors errorMode  Custom  existingResponse  Replace  gt           lt remove statusCode  404   gt           lt error statusCode  404  path  App Errors NotFound  responseMode  ExecuteURL   gt       lt  httpErrors gt   lt  system webServer gt    Problems with this solution    Only works on IIS 7   Does not comply with objective  2  automatically  It must be programmed manually  It obscures application level http exceptions  E g  can t use customErrors section  System Web Mvc HandleErrorAttribute  etc  It can t only show generic error pages     4    lt system web gt       lt customErrors mode  On  gt           lt error statusCode  404  redirect    Errors NotFound   gt       lt  customError gt   lt  system web gt    and   lt system webServer gt       lt httpErrors errorMode  Custom  gt           lt remove statusCode  404   gt           lt error statusCode  404  path  App Errors NotFound  responseMode  ExecuteURL   gt       lt  httpErrors gt   lt  system webServer gt    Problems with this solution    Only works on IIS 7   Does not comply with objective  2  automatically  It must be programmed manually  Does not comply with objective  3  in cases  2    3    5     People that have troubled with this before even tried to create their own libraries  see http   aboutcode net 2011 02 26 handling-not-found-with-asp-net-mvc3 html   But the previous solution seems to cover all the cases without the complexity of using an external library

User · Answer

The only way I could get  cottsak s method to work for invalid controllers was to modify the existing route request in the CustomControllerFactory  like so   public class CustomControllerFactory   DefaultControllerFactory       protected override IController GetControllerInstance RequestContext requestContext  Type controllerType                try                       if  controllerType    null                  return base GetControllerInstance requestContext  controllerType                else                 return ObjectFactory GetInstance controllerType  as Controller                    catch  HttpException ex                        if  ex GetHttpCode       int HttpStatusCode NotFound                                requestContext RouteData Values  controller      Error                   requestContext RouteData Values  action      Http404                   requestContext RouteData Values Add  url   requestContext HttpContext Request Url OriginalString                    return ObjectFactory GetInstance lt ErrorController gt                               else                 throw ex                      I should mention I m using MVC 2 0

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Posting an answer since my comment was too long     It s both a comment and questions to the unicorn post answer    https   stackoverflow com a 7499406 687549  I prefer this answer over the others for it s simplicity and the fact that apparently some folks at Microsoft were consulted  I got three questions however and if they can be answered then I will call this answer the holy grail of all 404 500 error answers on the interwebs for an ASP NET MVC  x  app    Pure Krome   Can you update your answer with the SEO stuff from the comments pointed out by GWB  there was never any mentioning of this in your answer  -  lt customErrors mode  On  redirectMode  ResponseRewrite  gt  and  lt httpErrors errorMode  Custom  existingResponse  Replace  gt    Can you ask your ASP NET team friends if it is okay to do it like that - would be nice to have some confirmation - maybe it s a big no-no to change redirectMode and existingResponse in this way to be able to play nicely with SEO    Can you add some clarification surrounding all that stuff  customErrors redirectMode  ResponseRewrite   customErrors redirectMode  ResponseRedirect   httpErrors errorMode  Custom  existingResponse  Replace   REMOVE customErrors COMPLETELY as someone suggested  after talking to your friends at Microsoft     As I was saying  it would be supernice if we could make your answer more complete as this seem to be a fairly popular question with 54 000  views   Update  Unicorn answer does a 302 Found and a 200 OK and cannot be changed to only return 404 using a route  It has to be a physical file which is not very MVC ish  So moving on to another solution  Too bad because this seemed to be the ultimate MVC ish answer this far

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Dealing with errors in ASP NET MVC is just a pain in the butt  I tried a whole lot of suggestions on this page and on other questions and sites and nothing works good  One suggestion was to handle errors on web config inside system webserver but that just returns blank pages    My goal when coming up with this solution was to    NOT REDIRECT  Return PROPER STATUS CODES not 200 Ok like the default error handling   Here is my solution   1 Add the following to system web section      lt system web gt        lt customErrors mode  On  redirectMode  ResponseRewrite  gt         lt error statusCode  404   redirect    Error 404 aspx    gt         lt error statusCode  500  redirect    Error 500 aspx    gt        lt  customErrors gt       lt system web gt    The above handles any urls not handled by routes config and unhandled exceptions especially those encountered on the views  Notice I used aspx not html  This is so I can add a response code on the code behind   2  Create a folder called Error  or whatever you prefer  at the root of your project and add the two webforms  Below is my 404 page    lt    Page Language  C   AutoEventWireup  true  CodeBehind  404 aspx cs  Inherits  Myapp Error  404    gt    lt  DOCTYPE html gt   lt html gt   lt head gt       lt meta charset  utf-8    gt       lt meta name  viewport  content  width device-width  initial-scale 1 0  gt       lt title  gt Page Not found lt  title gt       lt link href   lt   ResolveUrl    Content myapp css    gt   rel  stylesheet    gt   lt  head gt   lt body gt       lt div class  top-nav  gt         lt a runat  server  class  company-logo  href      gt  lt  a gt       lt  div gt       lt div gt           lt h1 gt 404 - Page Not found lt  h1 gt           lt p gt The page you are looking for cannot be found  lt  p gt           lt hr   gt           lt footer gt  lt  footer gt       lt  div gt   lt  body gt   lt  html gt    And on the code behind I set the response code  protected void Page Load object sender  EventArgs e        Response StatusCode   404      Do the same for the 500 page  3 To handle errors within the controllers  There s many ways to do it  This is what worked for me  All my controllers inherit from a base controller  In the base controller  I have the following methods  protected ActionResult ShowNotFound         return ShowNotFound  Page not found           protected ActionResult ShowNotFound string message        return ShowCustomError HttpStatusCode NotFound  message      protected ActionResult ShowServerError         return ShowServerError  Application error           protected ActionResult ShowServerError string message        return ShowCustomError HttpStatusCode InternalServerError  message      protected ActionResult ShowNotAuthorized         return ShowNotAuthorized  You are not allowed             protected ActionResult ShowNotAuthorized string message        return ShowCustomError HttpStatusCode Forbidden  message      protected ActionResult ShowCustomError HttpStatusCode statusCode  string message        Response StatusCode    int statusCode      string title           switch  statusCode                case HttpStatusCode NotFound              title    404 - Not found               break          case HttpStatusCode Forbidden              title    403 - Access Denied               break          default              title    500 - Application Error               break            ViewBag Title   title      ViewBag Message   message      return View  CustomError        4 Add the CustomError cshtml to your Shared views folder  Below is mine    lt h1 gt  ViewBag Title lt  h1 gt   lt br   gt   lt p gt  ViewBag Message lt  p gt    Now in your application controller you can do something like this   public class WidgetsController   ControllerBase      HttpGet    public ActionResult Edit int id          Try              var widget   db getWidgetById id          if widget    null            return ShowNotFound                or return ShowNotFound  Invalid widget            return View widget             catch Exception ex                 log error        logger Error ex         return ShowServerError                  Now for the caveat  It won t handle static file errors  So if you have a route such as example com widgets and the user changes it to example com widgets html  they will get the IIS default error page so you have to handle IIS level errors some other way

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I went through most of the solutions posted on this thread  While this question might be old  it is still very applicable to new projects even now  so I spent quite a lot of time reading up on the answers presented here as well as else where   As  Marco pointed out the different cases under which a 404 can happen  I checked the solution I compiled together against that list  In addition to his list of requirements  I also added one more     The solution should be able to handle MVC as well as AJAX WebAPI calls in the most appropriate manner   i e  if 404 happens in MVC  it should show the Not Found page and if 404 happens in WebAPI  it should not hijack the XML JSON response so that the consuming Javascript can parse it easily        This solution is 2 fold    First part of it comes from  Guillaume at https   stackoverflow com a 27354140 2310818  Their solution takes care of any 404 that were caused due to invalid route  invalid controller and invalid action    The idea is to create a WebForm and then make it call the NotFound action of your MVC Errors Controller  It does all of this without any redirect so you will not see a single 302 in Fiddler  The original URL is also preserved  which makes this solution fantastic       Second part of it comes from  Germ  n at https   stackoverflow com a 5536676 2310818  Their solution takes care of any 404 returned by your actions in the form of HttpNotFoundResult   or throw new HttpException      The idea is to have a filter look at the response as well as the exception thrown by your MVC controllers and to call the appropriate action in your Errors Controller  Again this solution works without any redirect and the original url is preserved      As you can see  both of these solutions together offer a very robust error handling mechanism and they achieve all the requirements listed by  Marco as well as my requirements  If you would like to see a working sample or a demo of this solution  please leave in the comments and I would be happy to put it together

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In MVC4 WebAPI 404 can be handle in the following way   COURSES APICONTROLLER         GET  api courses 5     public HttpResponseMessage lt Courses gt  Get int id                HttpResponseMessage lt Courses gt  resp   null           var aCourse    courses Where c   gt  c Id    id  FirstOrDefault             resp   aCourse    null   new HttpResponseMessage lt Courses gt  System Net HttpStatusCode NotFound    new HttpResponseMessage lt Courses gt  aCourse            return resp          HOME CONTROLLER  public ActionResult Course int id        return View id       VIEW   lt div id  course  gt  lt  div gt   lt script type  text javascript  gt      var id    Model      var course       course          ajax               url    api courses     id          success  function  data                course text data Name                      statusCode                404  function                                  course text  Course not available                                          lt  script gt    GLOBAL  public static void RegisterRoutes RouteCollection routes        routes IgnoreRoute   resource  axd   pathInfo          routes MapHttpRoute          name   DefaultApi           routeTemplate   api  controller   id            defaults  new   id   RouteParameter Optional               routes MapRoute          name   Default           url    controller   action   id            defaults  new   controller    Home   action    Index   id   UrlParameter Optional              RESULTS

[asp.net-mvc] How can I properly handle 404 in ASP.NET MVC?

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