Conclusion

ISAPI filters are used much less frequently than ISAPI extensions, and with good reason. Filters are more difficult to create, maddening to debug, and a potential drain on performance. Indiscriminate use of filters can cause a previously speedy application to become slow, and developers of other parts of the application need to be conscious of any modifications your filter will make to data destined for the browser client. Even with these limitations, they have their place in the toolbox of any Web developer.

If you need to create a Web application that must use custom authentication or automatically modify the appearance of lots of content in the Web application, filters can't be beat. In fact, filters are just about the only way to do these things.

In the next chapter we will shift gears and look at some of the problems with creating a Windows 2000 server-based application that must communicate with multiple clients and still offer reasonable performance. Chapter 13 will delve into some of the issues involved in leveraging the server-side capabilities of Microsoft SQL Server from your server-based application.