Chapter 5: The Lowdown on Web Services

Overview

Ask Microsoft what .NET actually is , and they ll tell you it s the software giant s XML Web services platform. Ask them what the XML Web services platform is, and they ll say it s a way of working that allows you to create software as a service.

Web services are a method of exposing your code functions to the world. You make certain functions available over HTTP. Other applications call these, and your application returns the results as XML. The receiving program then parses the response and continues processing.

With the .NET Framework, Microsoft provides ASP.NET for Web development. Included under this header is Microsoft s implementation of this new Web service industry communication standard. And, as we saw in the first paragraph, it s so important that Microsoft considers it to be the heart of .NET.

Why is it so important? In the future, Microsoft expects to see a world thriving on Web services, living on a dream of distributed computing. If your application needs to perform some complicated processing, it ll just tap into an external Web service to do the job, rather than requiring hours of extra development time.

Indeed, there are even unofficial plans for applications such as Microsoft Word to be supported by numerous Web services, maybe as a mechanism to allow users to access their documents from any machine in the world or perhaps as a way to actually supply and update the software, potentially cutting down on piracy and distributing updates in a more streamlined fashion. You could, in theory, end up merely hiring Word from Microsoft, or paying an annual subscription fee.

But, whatever the future holds, the truth is that Web services as they stand today are useful: they enable you to get computers talking together.

And you can create Web service applications in just a few lines of code. Yes, the Web services standard is built on XML and HTTP, but .NET is the first mainstream language to hide all this complexity from you. You simply need to write your functions, tell Visual Basic .NET which you want to expose, and then write other applications to consume those functions.

If you re new to Web services, you ll want to get acquainted with the Essentials in this chapter. Many authors write whole books on the topic, but all the vital stuff is listed here, with a few short bulleted points.

Of course, all the real juice comes with the Developer Secrets . Here, you ll learn the five crucial things you need to do before publicizing your service, figure out how to spy on your neighbors by tapping into TerraServer, plus learn how caching can make your services run like lightning.

Raring to go? Let s get busy!