ASP.NET: What does this HttpModule do? System.ServiceModel.Activation.HttpModule

Question

Can anyone tell me the purpose of this HttpModule? It's showing up on my HttpModuleCollection list, but I don't know what's it's for.

System.ServiceModel.Activation.HttpModule

I can't find any documentation on it.

Answer 1

System.ServiceModel.Activation.HttpModule come from because you installed "Microsoft .NET Framework 3.5.1" / "Windows Communication Foundation HTTP Activation" feature. If you don't need the feature you can uninstall it of remove the module from your web.config. The less unused modules you load the more quickly run your web application.

If you install this feature after the installation of .NET 4 framework on your server you can receive problems described in http://blogs.iis.net/webtopics/archive/2010/04/28/system-typeloadexception-for-system-servicemodel-activation-httpmodule-in-asp-net-4.aspx.

In general an HTTP module is called on every request in response to the BeginRequest() and EndRequest() events. As a result, the module runs before and after a request is processed. In the section "How HTTP Modules Work" on http://msdn.microsoft.com/en-us/library/bb398986(v=VS.100).aspx you can read more about HTTP modules.

http://msdn.microsoft.com/en-us/library/ms227673.aspx describes how to create a Custom HTTP Module. Some small custom modules can be really helpful. For example, you can read in How to remove the ".svc" extension in RESTful WCF service? a code example (which originate from the book "RESTful .NET", Chapter 5, page 96) "Removing the .SVC Extension from WCF REST URLs". In http://www.west-wind.com/weblog/posts/570695.aspx you can read how to do the same with respect of "IIS 7 Rewrite Module".

The general information about HTTP module is not a part of your question, but I inserted it to better understanding what Activation.HttpModule do, and what other more useful modules you can use or write yourself.

Answer 2

This module is what allows WCF (Windows Communication Foundation) services to work (starting in .net Framework 3.0).

You can safely ignore it and it shouldn't cause trouble. If you really want to get rid of it, you can remove it from your root web.config file (e.g. in \Windows\Microsoft.NET\Framework\v4.0.30319\Config\web.config). But I suggest leaving it there just in case you need WCF at some point.