In This Chapter
Exploring the basic principles of service-oriented apps
Building service-oriented apps
Making XML Web services available
A Web service is just the provision of functionality over the Internet using an open interface. A Web page provides functionality that you can see; a Web service provides the underlying data, in a format that you can use in another application.
Web services are straightforward — at least until the software manufacturers start messing with them. Web services are standards driven, just as HTML is, and the World Wide Web Consortium (W3C) owns their documentation. Web services have been a hot topic for the past decade, but only in the past five years or so (in step with the ubiquitous nature of the Internet) have they become a viable option for the delivery of hard-to-find software functionality.
A few different Web services formats exist in the .NET world, and they solve two basic problems:
Making part of your application available past the physical boundary of the application.
Making a distributed middle to your application so that you can scale paragraphs if your site suddenly has a lot of traffic.
After covering a few Web service principles, I present some code to show you how each format works.
Web services provide a way to extend methods past the normal boundary of a software system. You usually write the something like the following chunk of code in order to start building a problem: ...