Programming Web Services with SOAP

Chapter 3.  Writing SOAP Web Services

In Chapter 2, we looked under the hood of SOAP at the XML underneath. In this chapter, we demonstrate how to create, deploy, and use SOAP web services using toolkits for Java, Perl, and Microsoft's new .NET platform. We cover the installation, configuration, and use of SOAP::Lite for Perl, Apache SOAP for Java, and Microsoft .NET for C#.

The task of creating and deploying web services is really not all that difficult, nor is it all that different than what developers currently do in more traditional web applications. The tendency on all platforms is to automate more and more of the gory details and tedious work in creating web services. Most programmers don't need to know the exact details of encodings and envelopes; instead, they'll simply use a SOAP toolkit such as those described here.

Web Services Anatomy 101

In Chapter 1, we touched briefly on the fact that a web service consists of three components: a listener to receive the message, a proxy to take that message and translate it into an action to be carried out (such as invoking a method on a Java object), and the application code to implement that action.

The listener and proxy components should be completely transparent to the application code, if properly implemented. The ideal situation in most cases is that the code doesn't even know it is being invoked through a web service interface, but that is not always possible, or desirable.

A good example of a seamless, simple web services ...