Once and for all what is the best routing approach to handle errors, exceptions and 404's in MVC

问题:

There are many articles on SO and the web in attempts to handle 404's and exceptions gracefully.

From what I have read the best advice seems to be have a route for 404's like so:

routes.MapRoute(     "404-PageNotFound",     "{*url}",     new { controller = "ErrorController", action = "PageNotFound" }     ); 

Then for other errors have the HandleError atribute on the Controller and have CustomErrors turned on in web.config so it goes to the error.cshtml page.

However I have read that if you get a exception that does not set the HTTP code to 500 the HandleError will not work.

Can we finally produce an answer/best practice that handles 404's/Exceptions/ASP.Net errors where we can apply to this to all our projects?

Thanks

回答1:

I use a simple error handling setup. Nice and simple. More info can be found at http://erictopia.com/2010/04/building-a-mvc2-template-part-7-custom-web-errors-and-adding-support-for-elmah/

Install ELMAH and have it handle all the errors.

Next create an Error controller. Add a catch all route like this:

routes.MapRoute(     "ErrorHandler", // Route name     "{*path}",      // URL     new { controller = "Error", action = "Index" } ); 

Then in web.config add this section:

<customErrors mode="RemoteOnly" defaultRedirect="/Error/Index">         <error statusCode="403" redirect="/Error/NoAccess" />         <error statusCode="404" redirect="/Error/NotFound" /> </customErrors> 

回答2:

No need to set up a 404 route. In global asax application start, set up a global filter to catch 404 where the controller exists but not the action, or if an action returns a 404 result.

        filters.Add(new HttpNotFoundFilterAttribute { Order = 99 }); 

where the filter is an ActionFilterAttribute with this override:

    public override void OnActionExecuted(ActionExecutedContext filterContext)     {         if (filterContext.Result !=null &&              (filterContext.Result.GetType() == typeof(HttpNotFoundResult) )         {             //You can transfer to a known route for example             filterContext.Result = new TransferResult(SomeAction, SomeController);         }     } 

And also in Application_Error, in case no controller exists:

        Exception ex = Server.GetLastError();         string uri = null;         if (Context != null && Context.Request != null)         {             uri = Context.Request.Url.AbsoluteUri;         }          Exception baseEx = ex.GetBaseException();          var httpEx = ex as HttpException;           if ((httpEx != null && httpEx.GetHttpCode()==404)                || (uri != null && Context.Response.StatusCode == 404) )              { /* do what you want. */                 //Example: show some known url                Server.ClearError();                Server.TransferRequest(transferUrl);              } 

To avoid handling 404 for static resources, you should install SP1 on Windows 7 or windows 2008 R2 to upgrade IIS7 and set in web.config:

... <modules runAllManagedModulesForAllRequests="false"> ... 

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