Book Review: SOA and WS-BPEL

I was recently sent a copy of “SOA and WS-BPEL” by Yuri Vasiliev and Packt Publishing for review. The book is subtitled, “Composing Service-Oriented Solutions with PHP and ActiveBPEL.” After reading the book, the subtitle is much more accurate than the primary title. The book is first and foremost a guide for constructing Web Services using the SOAP extension for PHP and building BPEL processes using ActiveBPEL. Secondarily, there is a discussion behind the principles of SOA and WS-BPEL. Clearly, the right audience for this book is the developer community. If you’re removed from day to day coding, the book may not be as valuable.

If you’re looking for hands-on examples, this book has plenty of them. It includes all of the building blocks necessary from building your first service in PHP to creating an orchestrated process using BPEL. I felt that there was more emphasis on the coding efforts than necessary, however, and not enough on some of the theory behind it. This was evident in some of the early examples. In the sections on PHP, the examples result in a service that stores an XML representation of a purchase order in a database. The examples in the book take the incoming XML, create a PHP array representation of the XML, then convert it back to a DOM representation for storage in the database. While I do not know whether this approach was due to a limitation of the SOAP extensions, as an architect, it left me shaking my head. If the service is simply a pass-through to a database, there’s no reason to take all the time to parse the XML, bind it to some internal data structure, and then turn that internal data structure back into XML. Continuing on, the example then added XML schema validation to the mix, but it was performed by a stored procedure in the database. If you understand the role XML Schema validation has in security, odds are that XML schema validation will have occurred long before we even reach the back end database.

The section on WS-BPEL followed a similar vein. The bulk of the book was simply focused on walking you through the steps necessary to perform the actions in ActiveBPEL, rather than on building a sound understanding of WS-BPEL. There were pages upon pages of instructions on what menus to select, items to click, etc. I was very surprised at the lack of screenshots or graphical representations of the processes in the book. More often than not, they recommended using the Source tab in ActiveBPEL to compare the BPEL document in the book to what should have appeared after going through all the actions. My personal view on BPEL is that I don’t ever want to see it. I want to leverage the modeling capabilities of any BPM tool, and let the tool worry about BPEL behind the scenes.

Overall, for a book heavily focused on the developer community using PHP and ActiveBPEL (somewhat of a narrow audience, in my opinion), it’s certainly a good walkthrough to get your feet wet. It’s not going to give you the architectural skills you need, but it will move you through a lot of material very quickly. For people who are quick studies and just want some solid examples, you may find this a decent investment. For someone looking for more theory and architectural principles behind SOA and WS-BPEL, I’d probably look elsewhere.

Disclosure: This book was provided to me at no cost for the purposes of reviewing it. If you’re interested in having me review a book, please contact me at todd at biske dot com.

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