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Accepted
Pure.Krome
Asked: 2010-03-18 22:51:58 +0800 CST

IIS is overriding my response content, if I manually set the Response.StatusCode

  • 772

Problem

when I manually set the HTTP Status of my response stream to, say, 404 or 503, IIS renders up the stock IIS content/view, instead of my custom view.

When I do this with the web development server (AKA. Cassini), it works correctly (that is, my content is displayed and the response.statuscode == my entered data).

Is there any way I can override this behaviour?

How To Replicate

Make a default ASP.NET MVC1 web application. Add the following route

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        "Default",
        "{*catchall}",
        new { controller = "Home", action = "Index" }
        );

}

Now replace the the HomeController's Index method with...

[HandleError]
public class HomeController : Controller
{
    public ActionResult Index()
    {
        Response.StatusCode = 404;
        return View();
    }
}
windows-server-2008 iis-7.5 asp.net-mvc

3 Answers

  1. Best Answer

    Ok - found the answer. As I expected, IIS is hijacking my non 200 responses. Not sure (ie. I'm not sure if this is the default behaviour OR it's because of a setting one of the team members updated in the machine config, etc...).

    Anyways, the key here is tell IIS to not handle any non-200 status result resources.

    How? Config entry in the web.config.

    <system.webServer>
    <httpErrors errorMode="DetailedLocalOnly" existingResponse="PassThrough"/>
    .... snipped other IIS relevant elements ... 
</system.webServer>

    Now, the key here is existingResponse="PassThrough" . That bad boy tells IIS to leave my resources alone if the HTTP status code != 200.

    Want more info? Sure: Read More about this Element on the Official IIS Website.

    • 21

  2. Another way to bypass this is to run the following code in your ASP application:

    Response.TrySkipIisCustomErrors = true;

    Source: https://stackoverflow.com/a/21271085/238753

    • 4

  3. Be carefull with that approach in general. You should NOT render a view on 404 status.

    • I think when a error status code is returned, IIS returns the status error page that is registered with it - not the output from processing. So, you can put a HTML page there (or a link to an aspx page). http://professionalaspnet.com/archive/2008/02/13/Enforcing-a-Custom-404-Page-in-ASP.NET.aspx has a nice explanation how to set up an error page.

    • But that is irrelvant. Quite a number of browsers by default do NOT show that output, but something set in the browser. So, if you rely on people seeing your 404 page - that may not happen. They may see the 404 page that is set up in the browser for them.

    • -2