Programming ColdFusion MX, 2nd Edition

Web Services Overview

Web services provide a new way to build loosely coupled applications from components. At a basic level, a call to a web service is similar to a remote procedure call. A client makes a request of a remote object, the object performs some action, and a response is sent back to the client. At a higher level, applications built from web services may be assembled from components local to the organization or geographically distributed across the Internet. Web services provide a framework for standardizing both the interface and transport layer for these applications. Figure 24-1 shows a basic web services architecture.

Figure 24-1. Web services architecture

Web services are really an aggregation of several technologies layered on top of common Internet protocols such as HTTP. To better understand just what web services are, as well as how they work, let’s break the architecture down into its major parts. There are four main components that make up a web service:

Extensible Markup Language (XML)

XML can be considered the foundation of the web services stack. It provides a standardized platform- and language-neutral format for exchanging data among applications. More information about XML can be found at http://www.w3.org/XML/. Additional information on working with XML in ColdFusion MX can be found in Chapter 22.

Web Services Description Language (WSDL)

WSDL is an ...