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Acknowledgments


Acknowledgments

Randy

First and foremost I would like to thank Nat Torkington, editor and friend. He brought this opportunity to me, and was amazingly patient as I struggled to get up to speed with the materials I was given. My friends Paul and Ami Echeverri, both tech writers, didn't help with the book so much as keep me sane and entertained while fielding the occasional question about writing.

Ryan Dietrich introduced me to XML-RPC (and Radiohead's "Kid A" CD) while he was contracting to Red Hat. I'm also grateful to Kevin Greene, Stephen Nelson, Mike Reynolds, and Sky Schultz from my time as a contractor at Hewlett-Packard, and to Matt Lanier, Paul Lindner, Jason Miller, Garth Webb, Tom Lancaster, Eric Chen, and Bob Moss from my time at Red Hat.

Thanks to all the technical reviewers, and especially to Pavel Kulchenko, who not only reviewed but contributed , and who also was quick to answer a barrage of questions as I was writing the chapters on SOAP::Lite .

Finally, I'd like to acknowledge the Perl community, in particular the perl5-porters community. Not for the creation and maintenance of Perl, as you might assume, but for the community they've built around it. It is because of this sense of community that I was able to grow from just another programmer using the language, to being able to contribute modules to CPAN and eventually write this book.

Pavel

I owe a debt of gratitude to many people who one way or another made this book possible.

I would like to thank to my wonderful coauthor, Randy Ray, who was the pleasure to work with. Special thanks to Tony Hong, Stephen Friedl, Igor Dvoeglazov, and others who reviewed the draft of the book for their sound technical advice and valuable feedback.

Thanks are due to the people in the Perl and SOAP communities; their enthusiastic support, contributions, comments, and insistence on clarity have all made some difference to the book.

Thanks to our wonderful technical editor, Nathan Torkington, who was gently persistent in his effort to get this book happen and contributed his knowledge and experience to make it great.

And last, but definitely not the least, I wouldn't be able to finish the writing without my family's patience and love (or maybe I would, but what would be the point). Even though they have no interest in the content of the book (at least for now), my son Daniil and my wife Alena provided the support and encouragement I needed. Thank you!


Chapter 1. Introduction to Web Services

The world is full of useful data and services offered by computer programs. But most of that data and most of those services are locked away. Web sites, designed for access by people and not programs, bury the information in an ever-changing morass of HTML. Communication protocols have been specific to applications and sometimes to operating systems. Precompiled libraries are useful only for particular programming languages on the system they were compiled for.

If you want to write a program to book a flight, check how much paid time off you have accrued, or find all the shows on TV that feature the stars of Buffy the Vampire Slayer , you're facing an uphill battle. All that data exists, but it's effectively inaccessible.

Sure, you could screenscrape HTML from web sites such as expedia.com and tvguide.com, but that puts you at the mercy of the web designers of those sites. Every time they decide to make their pages look prettier, you'll have to rewrite your screenscraper.

You might be able to wangle access to the machine that runs the payroll system, but it's unlikely . You might even know the programming language the payroll software was written in. But can you figure out the database structure?

Web services are all about enabling computers to communicate with each other, opening up services and data. Built on open standards, the way that the Web is, web services offer convenient standard ways to open up the functionality of your applications to other applications.

In this chapter you'll learn a bit about the history of web services and the current lie of the land ”what systems you can choose from, where the hype exceeds reality, and so on.