Weird "The file '/DefaultWsdlHelpGenerator.aspx' does not exist" error when remapping WebService HttpHandler

I have dynamic CMS-driven (custom rolled, I know, wheels, etc. but not my decision!) site, which uses an HttpModule to direct content. I have found that .asmx resources were not working. After investigation, I figured out that this was because I had essentially overridden the handler by taking the request out of the overall pipeline.

So I am now detecting if the resource exists and is an .asmx file, and handling accordingly. Which I think is to create a WebServiceHandler using WebServiceHandlerFactory and then remapping it.

This works fine with a ?wsdl querystring, but ask for the URI itself and you get (at point indicated by asterisks):

System.InvalidOperationException was unhandled by user code

Message=Failed to handle request. [snip] InnerException: System.InvalidOperationException Message=Unable to handle request. Source=System.Web.Services InnerException: System.Web.HttpException Message=The file '/DefaultWsdlHelpGenerator.aspx' does not exist.

Note the final InnerException. This thread appears to suggest a corrupt .NET Framework install, but the file is present in the 4.0 Config folder. I suspect a mistake on my part. Am I remapping incorrectly?

public class xxxVirtualContentHttpModule : xxxHttpModule
{
        protecte开发者_StackOverflow社区d override void OnBeginRequest(IxxxContextProvider cmsContext, HttpContext httpContext)
        {
            string resolvePath = httpContext.Request.Url.AbsolutePath;

            // is path a physical file?
            IRootPathResolver rootPathResolver=new HttpServerRootPathResolver(httpContext.Server);
            string serverPath = rootPathResolver.ResolveRoot("~" + resolvePath);

            if (File.Exists(serverPath))
            {
                if (Path.GetExtension(serverPath).Equals(".asmx", StringComparison.CurrentCultureIgnoreCase))
                {
                    WebServiceHandlerFactory webServiceHandlerFactory = new WebServiceHandlerFactory();
                    IHttpHandler webServiceHttpHandler = webServiceHandlerFactory.GetHandler(httpContext, "Get", resolvePath, serverPath); // *****

                    httpContext.RemapHandler(webServiceHttpHandler);
                }
            }

        }

Update

I have removed all references to the HttpModules and this issue still occurs, meaning it has nothing to do with the CMS portion of the system.

Solved it.

There seems to be a new configuration added to web.config:

<system.web>
    <webServices>
        <wsdlHelpGenerator href="DefaultWsdlHelpGenerator.aspx" />
    </webServices>
</system.web>

Removed this, and it all works.