Overview of Internet Information Services 5.0
Overview of Internet Information Services 5.0 |
|
ISAPI is an Internet API for extending IIS 5.0 and other HTTP servers that support its interface. ISAPI filters are dynamic-link libraries (DLLs) that allow preprocessing of requests and postprocessing of responses, which in turn allows for site-specific handling of HTTP requests and responses. These filters can also be run out of process, in order to improve reliability and to consume fewer resources than CGI applications.
IIS 5.0 contains several built-in ISAPI filters, such as one for compression. You can also buy and install third-party filters, such as an authentication filter, to do tasks not covered by the built-in filters. For information about installing filters, see the “Installing ISAPI Filters” topic in the IIS 5.0 online product documentation.
If you don’t find a built-in filter or one that you can buy, you can build a custom filter. For example, you can write an ISAPI DLL to intercept specific server events and perform appropriate actions. This functionality is especially useful in implementing server security. For more information, see the “ISAPI Filters Overview” topic in the IIS 5.0 section of the SDK documentation on MSDN.
You will find several sample ISAPI filters on the Microsoft® Windows® 2000 Server Resource Kit companion CD.