Professional Microsoft IIS 8

Extensibility Overview

The application programming interface (API) provided for developers to extend IIS is quite certainly the most powerful yet delivered by the IIS developer team. This API, in fact, is exactly the same API used by the IIS team itself to create the default modules supplied with IIS out-of-the-box.

This means that the creators and maintainers of IIS are no longer required to wait for a major OS release or service pack, update, or patch to deliver enhanced or new functionality. Cosmetic adjustments, flaws, or security vulnerabilities alike can be addressed by simply replacing the relevant module without affecting the remaining system in general.

As developers, the exciting implication is that we can now not only add our own functionality by creating a custom pluggable module, but we can also completely replace any default module shipped with IIS.

Indeed, if you are so inclined, you could take the basic core server, strip out all default modules, and write your own modules from scratch. (Why anyone would want to do that, though, is questionable!)

Those of you already familiar with the old IIS 6.0 ISAPI model will find the existing API strikingly familiar. The HTTP Module API provides all the notifications available to ISAPI and more, including access to user objects; global notifications, such as application startup or shutdown; and change notifications, including changes to configuration and content.

For this reason, although the IIS Developer Team has been careful ...