InformationWeek
Defining The Business Value Of Technology
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August 14, 2000 |
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Web Development Platforms
Stealing Java's Thunder
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The toolkit includes documentation, a set of ActiveX objects that handles the packaging and unpackaging of method invocations, sample code, and specification documents.
SOAP will be the basis for the next generation of Active Server Pages, the engine that powers Microsoft's Web server and enables code execution as Web pages are delivered to the client. Unlike the current version of ASP, ASP+ is closely integrated with Windows 2000 as an operating system service, which will make it far more scalable and flexible. ASP+ is the primary technology on which the new Visual Studio Web features are based.
The two main Visual Studio.net features built with SOAP are Web Services and Web Forms. Web Services provide a way for one Web site to use the features of another site. Say, for example, that a Web site provides shopping services to consumers. Rather than developing its own data and storing it on a site, the site can use Web Services from other sites to request information about a particular brand of kayak that a consumer wants.
The Web Services feature assembles the request in a SOAP package, sends it off to one or more servers, and gets the kayak data back. This can be done with Common Gateway Interface scripts and other technologies, but it requires way too much messy coding.
A Web page can pull together various Web Services provided by different Web sites--for free or for a fee--such as currency conversions, weather and airplane flight status, and financial calculations. This eliminates the creation of these services from scratch, making possible standard information schemas, and potentially opening a market for commercial Web services.
Web Forms is another feature that will be incorporated in Microsoft's development products. Visual Basic 6.0 included a preliminary version of Web Forms, called WebClasses, which provided an interface between Visual Basic code and Active Server Pages on the Web server. Web Forms build on WebClasses but allow development in any of the Visual Studio language tools and are more closely integrated with the Web server. This means that Web sites developed with these tools will scale and perform far better than with the current tools.
Web Forms are aimed at eliminating slow, stunted script code from sophisticated Web sites. Forms consist of an HTML file containing the visual representation of the page and a source code file with custom event-handling code. This is a server-side technology, working with ASP+, to deliver HTML pages to the client browser.
Programming a Web Form is similar to designing a traditional Visual Basic form: Add a Web Form to the project, drop controls on the design surface, and double-click on the control to open the code window to write event-driven procedures and other code. But unlike Web Classes and VB forms, the code behind Web Forms can be any of the Visual Studio languages. And because all the code is compiled into dynamic link library (DLL) files, it executes much faster than the interpreted scripting code used for most Web development today.
WebClasses, by the way, appear to be on the verge of becoming an abandoned technology. It's included in future versions of Visual Basic but isn't expected to be enhanced in any future releases. It will be available only for backward-compatibility purposes.
Both Web Services and Web Forms are features of ASP+, but the development products in Visual Studio will include tools that can incorporate them into custom applications.
Unlike Microsoft's Distributed Component Object Model, Web Services can be platform-independent because they're based on SOAP, and therefore on XML. SOAP won't replace DCOM any time soon, however, because DCOM is so deeply entrenched in Windows applications, and DCOM has much more flexibility than SOAP. But Distributed Component Object Model is a Windows-only technology and burdens the network with far more overhead traffic than SOAP.
SOAP interfaces are simpler than DCOM to set up and use. They require only a listener application that receives the method request and directs it to the appropriate service. The server publishes method specifications using XML-based Service Description Language, which is similar in purpose to DCOM's Interface Definition Language for building type libraries, but is much simpler to use.
To support all these new Web development features, Microsoft is making some major changes to the tools that make up the Visual Studio suite. The biggest visual change is the integrated development environment, the main application where a developer structures an application, writes code, and debugs it.
Version 6.0 and earlier had at least three different development environments that a developer had to learn when using all the tools. This meant that as developers worked on different sections of an application written in different languages--such as components in Visual Basic, low-level system routines in Visual C++, and interface applets in Java--they would essentially be running different applications with different interfaces and tools.
But the new version will host all of the development tools in a single development environment, loading code from any of the languages into a single host environment. This will make developers far more productive and make it easier to develop a piece of an application in the language best suited for its specific purpose.
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Illustration by David Goldin
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