December 17, 1998 Web posted at: 4:00 PM EST by Brooks Talley

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(IDG) -- Using Microsoft's Internet Information Server (IIS) and several of its accompanying products and technologies, businesses can operate everything from the smallest Web site running on Windows NT Workstation up to mission-critical Internet commerce sites on huge farms of NT Servers. However, IIS' ability to serve such a wide range of roles can be both a blessing and a curse.

In general, Web sites can be broken down into roughly three levels of complexity: a static site, a site with dynamic content, and a site with complex business applications. While IIS is suitable for these types of sites, the more complex a site becomes, the more IIS buckles under the strain.

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Basic sites

For organizations that are just starting to put a Web site together or that plan to place relatively meager demands on their site, IIS is a good place to start. The software's appeal for basic, low-volume Web sites revolves around two key points: a low price and the ease of use and administration for novice Web developers and server administrators alike. An IIS server can be as simple as a low-end NT workstation, and IIS itself doesn't cost anything extra because it comes with the operating system.

Another key attraction for novice users is IIS' built-in support for FrontPage Extensions -- a technology that more closely integrates Web servers with content design programs. FrontPage Extensions work in conjunction with Microsoft's FrontPage Web editor to greatly simplify site design. It is eminently possible for someone with no experience running a Web server or designing Web pages to use IIS with FrontPage to put up a respectable Web page in no time at all.

FrontPage quickly loses its luster, however, as users become more experienced. In order to get things just right, you will need finer control over page layout than FrontPage allows. FrontPage also is well known for scrambling page formatting (especially scripts), so designers who want to be able to work directly with HTML will quickly tire of having the spacing of their scripts adjusted for them.

In addition, FrontPage Extensions are notoriously insecure, and a novice administrator may be lulled into a false sense of security after just tossing up an IIS server with the extensions on it. Also, novice administrator probably won't be aware of the need to install the various "hot fixes" for NT's security problems.

Dynamic Web content

After setting up a basic, static Web site, the next natural step is to add some interactivity and dynamic content to the mix. It's time to work with either Visual Interdev, Microsoft's higher-end site development tool, or something like Allaire's Homesite. Both are code-oriented, rather than graphical, and both are more appropriate for serious Web development because they don't try to do too much for the developer.

Of course, these sophisticated tools go hand in hand with using some of the more advanced features of IIS. Probably the first thing you will start doing at this stage is using Active Server Pages (ASPs) to add some dynamic content to a site. Dynamic content can be simple at first -- adding a page counter or customizing a greeting -- and eventually it can be more complicated, such as using calendars or dynamically generated JavaScript. ASPs are also ideal for processing forms. They work by embedding a scripting language into what was previously a pure HTML file. They support VBScript and Jscript, Microsoft's implementation of JavaScript, out of the box.

Complex business applications

IIS really becomes a ready-to-run platform for line-of-business applications when you use it as a front end to a database. Connecting a Web site to a database opens up a world of possibilities such as order tracking, data entry, and electronic commerce. ASPs are well suited for this connection, and VBScript has a wide array of data access tools that are both flexible and powerful. Basic operations, such as looking up records in a database, are an absolute breeze to write using Visual Basic, and even inexperienced coders should be able to get along with the help of the sample files that come with IIS. What's more, Visual Interdev has several tools that help make it easier to program database front ends. However, these tools are best suited to simple queries and data presentation -- if you're going to do something truly complex, you'll have to code by hand.

Initially, ASPs work well with Microsoft Access as a database, but Access isn't really meant for multiuser applications such as a busy Web site. By avoiding Access altogether, you won't have to wonder whether the problems you encounter during development are your own fault or a symptom of Access' limited capabilities. Starting out with Microsoft's more robust SQL Server is a better idea, though it does add to the initial cost.

If your organization is like others that have discovered the benefits of establishing a Web site, you may have a monster on your hands because of the inevitable way Web sites organically grow and because you didn't centrally plan for the final design. Lack of attention to code reusability and proper programming structure can make it a nightmare to maintain code -- all because you started with the dynamic content limited to "Good evening, [username]" and let it grow from there. At this stage, most IIS applications go through something between a rewrite and a major housekeeping effort. Commonly used code needs to be isolated into "include" files that are reused, and likewise with constants that may appear in more than one place.

In addition, you may have learned that VBScript, while powerful, simply isn't fast enough for some processing. That limitation can be overcome by moving business logic into SQL stored procedures and moving slower code into stand-alone ActiveX components. Those components are compiled binary files that act something like Windows DLLs: They include a bunch of logic and an interface for getting to it. ActiveX controls simplify application design by tightly grouping related functions together, as well as performing faster than VBScript.

Transaction Server

All of that work leads onto the next step on the slippery slope: using Microsoft Transaction Server (MTS) to further compartmentalize transactions. At first glance, the name suggests something database-centric, but in this context, a "transaction" is everything from creating an ActiveX component to a page load on an MTS-enabled site. MTS provides a saner framework for using ActiveX components, treating each component as an object that can be created, checked out, and ultimately reused. It also allows "packaging" of multiple components to further organize things. However, MTS is a relatively new product, and everyone knows Microsoft's record with new products. In my experience, adding MTS to a site greatly helps organization, but it can result in performance and stability problems.

If you've come to this point, you've basically pushed IIS to its limit, and you may be wondering why you started down this path in the first place. IIS is a great Web platform and has a lot to recommend it, but if you take it to the extreme, the experience can be harrowing. Contending with the complexity introduced by using NT, IIS, ASPs, ActiveX, SQL, and MTS all at the same time can make troubleshooting a real nightmare. You may even have second thoughts about using IIS and fantasize about moving to some sort of Unix-based application Web server. However, these too have their own quirks and issues. Once you've taken the time and effort to come this far, there's a lot to be said for sticking with the devil you know.

Brooks Talley is Test Manager at Infoworld's Test Center.