Web Services Explained, Solutions and Applications for the Real World
XML is extremely important in the Web services scheme of things because XML provides the wrapper in which readable and manipulatable data can be passed between disparate applications.
Web services mechanisms such as UDDI, WSDL, and SOAP are immature from a reliability, security, manageability, routing, and transaction handling perspective when compared to other communications architectures such as CORBA, EDI, and COM. Hence, many early adopters are using other communications architectures to pass XML data until formal Web services standards mature a bit more.
Chapter 2 described the concept of program-to-program communications in greater detail. It showed how Web services program-to-program communications actually works by illustrating how: (1) data is packaged in a common format that can be read by cooperating applications (XML); (2) programs are able to find each other (UDDI); (3) programs are able to share information and negotiate with each other (WSDL); (4) programs are able to commence communications and transfer data (SOAP); and (5) programs use a common network (the Internet) for program-to-program communications.
This chapter takes a closer look at all of these Web services technologies. How do they work? What specifically do they do? What additional standards efforts are underway to support the basic Web services protocols? This chapter concludes with a discussion about other options available to your organization that can be used to compliment or replace Web services protocols, registries, and formats. Many of the research examples (account scenarios/anecdotes) contained later in this book show that early adopters are not using all of the Web services protocols and services in the initial solutions that they have built. This chapter examines alternate approaches that are being used until Web services protocols become more mature.