Chapter 12. SOAP

SOAP is the Simple Object Access Protocol. If you haven’t heard of it by now, you’ve probably been living under a rock somewhere. It’s become the newest craze in web programming, and is integral to the web services fanaticism that has taken hold of the latest generation of web development. If you’ve heard of .NET from Microsoft or the peer-to-peer “revolution,” then you’ve heard about technologies that rely on SOAP (even if you don’t know it). There’s not one but two SOAP implementations going on over at Apache, and Microsoft has hundreds of pages on their MSDN web site devoted to it (

In this chapter, I explain what SOAP is, and why it is such an important part of where the web development paradigm is moving. That will help you get the fundamentals down, and prepare you for actually working with a SOAP toolkit. From there, I briefly run over the SOAP projects currently available, and then delve into the Apache implementation. This chapter is not meant to be the complete picture on SOAP; the next chapter fills in lots of gaps. Take this as the first part of a miniseries; many of your questions at the end of this chapter will be answered in the next.

Starting Out

The first thing to do is get an understanding of what SOAP is. You can read through the complete W3C note submission, which is fairly lengthy, at When you take away all of the hype, SOAP is just a protocol. It’s a simple protocol (to use, not necessarily ...

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