Professional ASP.NET 3.5 Security, Membership, and Role Management with C# and VB

7.2. IIS 7.0 Wildcard Mappings

IIS 6 introduced the concept of wildcard mappings. Wildcard mappings are a way to tell IIS 6 that every incoming request, regardless of file type, should be routed to one or more ISAPI extensions. Since these extensions are configured in IIS 6 to handle any incoming request, the term "wildcard" is used to indicate that request handling is independent of a specific file type. Not only can you configure a single ISAPI extension with wildcard mappings, but you can also configure multiple ISAPI extensions to act as a chain of wildcard mappings. IIS 6 will walk through the list of configured mappings in sequence, passing control of the request to each extension in turn.

After the wildcard mapped extensions have completed their processing, IIS 6 passes control of the request to the extension or internal runtime handling appropriate for the file type. The IIS 6 ISAPI API also included additional functionality for extension authors that know their extensions will be used as part of a wildcard mapping. In the case of ASP.NET 3.5, the DefaultHttpHandler class (covered in the "DefaultHttpHanlder" section this chapter) includes extra logic that allows ASP.NET to gain control of a request for non-ASP.NET resources both before and after the default processing for that request occurs. This enables you to integrate ASP.NET 3.5 so that it can perform both preprocessing and postprocessing of a classic ASP request.

When an application is hosted in IIS 7.0 and configured ...