The core idea behind this book is simple: after years of hype, what are the major players really doing with web services? Standard bodies may wrangle and platform vendors may preach, but what technologies are actually in use?
Think of this book as a field guide to the wild and woolly world of nontrivial deployed web services. The heart of the book is a series of projects that demonstrate the use and integration of Google, Amazon, eBay, PayPal, FedEx, and many more web services. Some of these vendors have been extremely successful with their web service deployments; for example, eBay processes over a billion web service requests a month.
Not all web services are created equal: some rely on a variety of strange formats; others require extensive and error-prone XML; and still others require a minimal knowledge of SOAP and WSDL. This book provides compelling examples of the value of SOAP and WSDL for the client developer. In Chapter 4, for example, you can compare the custom bindings required for working with complex XML data types against the generation of SOAP binding generation from WSDL.