Introduction

The growth of the Internet demands that businesses provide clients with a better, more efficient user experience. Existing technologies have made it very difficult to make applications communicate with each other across businesses. The varied resources used, such as operating systems (OSs), programming languages and object models, pose big challenges to application integrators.

Web Services have been created to solve the interoperability of applications across operating systems, programming languages, and object models. Web Services can achieve this by relying on well supported Internet standards, such as Hypertext Transfer Protocol (HTTP) and Extensible Markup Language (XML).

In this chapter, we tell you why Web Services are an important new development in the area of Internet standards, and what business problems they address. We talk about the Simple Object Access Protocol (SOAP), which lets you exchange data and documents over the Internet in a well-defined way, and related standards to describe and discover Web Services. Finally, we cover techniques for error handling and state management and discuss how Web Services integrate with the Microsoft .NET platform.

The Case for Web Services

In a broad sense, Web Services may be defined as Internet-based modular applications that perform specific business tasks and conform to a specific technical format, to quote Mark Colan from IBM. If you accept this definition, you may have very well already developed a number of Web Services. However, the crux of this definition is the specific technical format. Similar to the way a network becomes more and more useful...