Question

Before I get started, I have followed the advice here:

Getting “The WebResource.axd handler must be registered in the configuration to process this request.” error

I had used the advice theren to fix a similar problem I’ve had in the past with an MVC 4 app running on a different server.

I’m trying to upgrade one of our websites to .Net 4.0 because I want to convert it to an MVC 4 app. I’m planning* on doing it piecemeal, and have spent a lot of time going through all of the objects in the old forms-based Web Site Project and setting them up so that they can run successfully on the .Net 4 framework as part of a hybrid (for the time being) site. Mostly that involved moving classes out of the App_Code folder and into regular folders and marking them to be copied/compiled.

Now I have a new problem. When I go to a page that tries to call an embedded resource, I get a WebResource.axd error:

The WebResource.axd handler must be registered in the configuration to process this request.

Stack Trace:

    [InvalidOperationException: The WebResource.axd handler must be registered in the configuration to process this request.

<!-- Web.Config Configuration File -->

<configuration>
    <system.web>
        <httpHandlers>
            <add path="WebResource.axd" verb="GET" type="System.Web.Handlers.AssemblyResourceLoader" validate="True" />
        </httpHandlers>
    </system.web>
</configuration>]
   System.Web.Handlers.AssemblyResourceLoader.GetWebResourceUrlInternal(Assembly assembly, String resourceName, Boolean htmlEncoded, Boolean forSubstitution, IScriptManager scriptManager) +4179118
   System.Web.Handlers.AssemblyResourceLoader.GetWebResourceUrl(Type type, String resourceName, Boolean htmlEncoded, IScriptManager scriptManager) +956
   System.Web.UI.ClientScriptManager.RenderWebFormsScript(HtmlTextWriter writer) +257
   System.Web.UI.Page.RenderWebFormsScript(HtmlTextWriter writer) +86
   System.Web.UI.Page.BeginFormRender(HtmlTextWriter writer, String formUniqueID) +1847
   System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +95
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +48
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) [phone]
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +246
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) [phone]
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +246
   System.Web.UI.Page.Render(HtmlTextWriter writer) +40
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) [phone]
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5290

LIS I’ve seen and fixed this error on another MVC 4 site I’d written from the ground up. It happens because ColdFusion is also installed on the server and is a known problem with IIS servers hosting ColdFusion and .Net applications. So I followed the advice here:

Getting “The WebResource.axd handler must be registered in the configuration to process this request.” error

I configured that site to run in “Classic” mode and it works fine.

But this time is different. I tried getting the app pool set to “Classic” mode. Our admins set it up that way for me, but then I ran into 404/500 errors. Then they enabled ISAPI and CGI, which got me back to the above WebResource.axd error, this time while running in Classic mode.

So I tried some of the other suggestions in the above link. Specifically, I followed this advice (same link, 2nd answer):

To do this, go to the site in question in IIS, double-click on “Handler Mappings” under the “IIS” section, and find the handler named something like “AboMapperCustom-XXXXXX” with “*” for the Path. Select the entry and click “Remove” in the sidebar. This will only remove the mapping for your application, so it won’t break any existing CF sites on the server.

When I put in a request for our admins to do that, I received this back:

“The AboMapperCustom-94661 * Handler is coming from the parent but is removed in the individual sites web.config – I can not remove them from the default/parent site because it will indeed break ColdFusion.”

I’ve tried the solution here http://blog.fredrikhaglund.se/blog/2008/08/26/solution-to-webresourceaxd-exception/ also and my httpHandlers section in web.config looks like:

<system.web>
   ...
   <httpHandlers>
     <add path="WebResource.axd" verb="GET" type="System.Web.Handlers.AssemblyResourceLoader" validate="true" />
     <add path="*/ext.axd" verb="*" type="Ext.Net.ResourceHandler" validate="false" />
     <add path="glimpse.axd" verb="GET,POST" type="Glimpse.Core.Handler" />
   </httpHandlers>

A big part of my problem is that I don’t have admin access to the IIS Server so I can’t go in and work this out myself. I’m fumbling around for what to do next and it seems I have a few choices:

1. Set up an error handler to catch this error and just redirect to an “Under Construction” page until that page gets rewritten for the new site. This is possible, but not ideal.
2. Somehow set up a filter to pick axd requests up before the Coldfusion mapping does (just a vague notion I have, not sure how/why it would work without further research).
3. Come up with another configuration request to run by our admins that might fix the problem.

Does anyone have any ideas related to #3 that will fix my problems? If not, I”ll probably end up doing a few hours of research into options 2 and 3 before ultimately just going with option 1. What might be the best way around this issue?

Answer 1

I figured out a fix for my problem.

After reading the ASP.Net Configuration settings for .Net 4.0

I found the remove Element for the httpHandlers section

When I add a remove to my httpHandlers like so:

<httpHandlers>
      <remove path="WebResource.axd" verb="GET"/>
      <add path="WebResource.axd" verb="GET" type="System.Web.Handlers.AssemblyResourceLoader" validate="true" />

It works!