An HttpModule is an assembly that implements the IHttpModule interface and handles events. ASP.NET includes a set of HttpModules that can be used by your application. For example, the SessionStateModule is provided by ASP.NET to supply session state services to an application. Custom HttpModules can be created to respond to either ASP.NET events or user events.
The general process for writing an HttpModule is:
- Implement the IHttpModule interface.
- Handle the Init method and register for the events you need.
- Handle the events.
- Optionally implement the Dispose method if you have to do cleanup.
- Register the module in Web.config.