Chapter 3. SOAP, WSDL, and UDDI Explained
IN THIS CHAPTER
If you are going to do any Web Service development, you need to have a basic understanding of what is going on under the covers. Because the underlying technology uses plain text to communicate, you do not need any fancy tools to view and makes sense of what is going back and forth. You do, however, need to understand how the messages are defined and what the different parts mean. Web Services use three different specifications to do different things. These specifications are
Web Services Description Language (WSDL)— Defines the Web Service interface
Universal Description, Discovery, and Integration (UDDI)— A Web Service that serves as a way to advertise and discover Web Services
These three items combine to form what you can think of as the first version of Web Services. Here, you have the foundation on which to build more complex items. SOAP specifies the general message format. WSDL states what messages a particular SOAP server accepts and describes the format of the messages and the types contained by those messages. UDDI functions as a registry for Web Services and is a Web Service in its own right.
In this chapter, you will explore these three topics so that you are familiar with the terminology and elements used by these three complementary technologies. By the end of the chapter, you should be relatively comfortable reading SOAP messages and WSDL files. Additionally, you will be able to dig into a UDDI registry and discover specific Web Services.