Question

I need to write a HttpHandler that will serve up JavaScript files which are embedded resources in .DLLs in my project. A reference in a view cannot directly see such a resource, so I planned to use a HttpHandler module that would intercept any request with a path /js/[file] , find a matching embedded file and return the script.

The problem is that my HttpHandler code is never called, despite trying lots of different settings in the section of web.config. I’m obviously missing something but with no error messages I cannot see what that is. All I ever get is a 404 from the static file handler.

Q1) Am I missing something obvious?

Q2) Is there a way to get IIS to tell me why it is not calling my handler?

Summary: I am testing on IIS Express (v8) for an ASP.NET MVC 4 application.

I created a simple library that implements IHttpHandler and added a reference to this in my test MVC application, and the following lines in web.config:

  <system.webServer>
    <validation validateIntegratedModeConfiguration="true" />
    <handlers>
      <add name="ejs" path="js/*" verb="*" type="EmbeddedJsHandler.EmbeddedJsHandler, EmbeddedJsHandler" preCondition="integratedMode" />

The library is there, but it is never called. Any request with /js/test.js or whatever just results in a 404 error.

So far I’ve tried lots of different configurations and settings in the handler code. I’ve tried preCondition, resourceType=”Unspecified”, modules=”IsapiModule” scriptProcessor=”%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll”

I’ve tried paths:

  js/*.js
  js/* 
  js/*.*

I’ve checked the integrated mode settings section (in system.webServer) is being used, and confirmed it is.

I’ve searched stack overflow for similar cases, and tried many of the possible solutions.. still no joy.

Heck even Jon Skeet has these sort of problems!
Why isn't my IHttpHandler being called?

Answer 1

Finally figured it out by accident – it was a missing routes.IgnoreRoute() in the RouteConfig.cs file – the MVC routing engine wasn’t configured to ignore this path, so was passing it to the static file handler.

Doh!