Why is ScriptResource.axd compressed, even though IIS compression is disabled?

Question

I run an ASP.NET application on IIS 6.0. Usually I have compression turned on for both dynamic and static files. However, I've turned compression off temporarily, but "ScriptResource.axd" is still sent compressed. This does not feel like a misconfiguration, as "WebResource.axd" is not compressed.

What is the difference between ScriptResource and WebResource, such that the former is still compressed? How is it getting compressed?

Thanks.

Answer 1

Web Resources are handled by the AssemblyResourceLoader class, which is designed to retrieve assembly resources and serve them to the Web browser. Web Resources are not compressed by default.

Script Resources are handled by the ScriptResourceHandler class, which takes care of all requests for embedded script files that are referenced through the ScriptManager class. Script Resources are automatically compressed with GZIP by default for HTTP delivery.