Question

I have created a very simple ASP.NET HttpHandler and for some reason it is not being called unless the user is logged on. I have it assigned to handle PNG images. For a first time visitor to the website, the handler is not called. After they logon, then it is called. I am using .NET 4, IIS7 on Windows 7 in Classic mode. The PNG images requested do not exist in the file directory.

namespace MyNS
{
   public class MyHttpHandler : IHttpHandler 
   {
       public bool IsReusable { get { return true; } }
       public void ProcessRequest( HttpContext context ) 
       { }
   }
}

In my web.config, I have …

<system.webServer>
    <handlers>
   <add name="MyPNG" path="*.png" verb="*" type="MyNS.MyHttpHandler" modules="IsapiModule" scriptProcessor="C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="None" preCondition="classicMode,bitness64" />
    </handlers>
</system.webServer>

Answer 1

First of all, if you are using IIS7 in classic mode, you must setup config in two places: link.

Also you need to exclude your handler from authentication:

<location path="myhandler URL">
            <system.web>
                    <authorization>
                            <allow users="*"/>
                    </authorization>
            </system.web>
</location>

UPDATE

OK, here is what I mean:

<location path="*.png">
            <system.web>
                    <authorization>
                            <allow users="*"/>
                    </authorization>
            </system.web>
</location>