Networking Bible

Chapter 23. Web Services

IN THIS CHAPTER

• Hypertext Transfer Protocol

• HTTP request/response mechanism

• Different technologies used to create Web services

• Service Oriented Architecture

In this chapter, I introduce the basis for creating and developing Web services. As more applications begin to migrate to the Internet, Web services will become increasingly important.

The Hypertext Transfer Protocol (HTTP) is the Application layer protocol that browsers use to transfer information. HTTP uses plain-text requests from a user agent or client to the server to request a resource, and the server responds with the appropriate resource in the appropriate format, provided that the request is valid. A set of status codes is defined to aid in negotiation and execution. In this chapter, you learn how HTTP messages are composed and executed.

HTTP can transfer information using HTML or XHTML, which, when processed by a browser, describes how to create and format a Web page. Web pages can contain either static or dynamic content. Some of the different ways in which dynamic content is controlled across a network are considered — server-side and client-side scripting, and CGI in particular.

A Web service is a mediated client-server application. An example of how a Web service can be implemented using SOAP as the communication or messaging protocol between service requestor and service provider will be presented. In a Web service, transactions are mediated by a service broker that runs on a third system. The ...