Question

Consider a Web.config file containing the following httpHandlers declaration:

<httpHandlers>
  <add verb="*" path="*" type="MyWebApp.TotalHandlerFactory"/>
</httpHandlers>

In other words, this handler factory wants to “see” all incoming requests so that it gets a chance to handle them. However, it does not necessarily want to actually handle all of them, only those that fulfill a certain run-time condition:

public sealed class TotalHandlerFactory : IHttpHandlerFactory
{
    public IHttpHandler GetHandler(HttpContext context, string requestType, string url, string pathTranslated)
    {
        if (some condition is true)
            return new MySpecialHttpHandler();

        return null;
    }

    public void ReleaseHandler(IHttpHandler handler) { }
}

However, doing it like this completely overrides the default ASP.NET handler, which means that ASP.NET pages and web services no longer work. I just get a blank page for every URL that doesn’t fulfill the “some condition” in the “if”. Therefore, it seems that returning null is the wrong thing to do.

So what do I need to return instead so that ASP.NET pages and web services are still handled normally?

Answer 1

It is not possible to do this in the general case.