Web Services are the newest excitement at the confluence of network, Internet, and distributed programming, and it is not surprising that Perl has come to provide a powerful interface to this in its libraries.

Perl is well known for its compact scripting capabilities, and has the ability to quickly create small programs to exercise capabilities. This makes it a good exploration and prototyping tool, although some may argue that past that stage, a more complete type checked language is more appropriate. In any case, this book is a good introduction to Web services and their usage of Perl.

Typical of an OReilly book, it is very concise, clear, and practical. Providing a good introduction through many short code samples, it does impress with the power to access remote information and services through simple scripts.

After a brief introduction, the book spends two chapters on Extensible Markup Language remote procedure calls (XML-RPC), using various remote procedure call (RPC) libraries. I doubt that most people purchasing the book had this in mind, as it is a much less standard or prevalent protocol for Web services. Their premise that it is a simpler and thus more efficient protocol is true, and perhaps this simplicity indeed makes it a good starting place. One thing I like about this coverage is that it shows the creation of both client and server components, and helps readers understand the overall process of these services.

The next and main portion of the book is the core material, covering simple object access protocol (SOAP), Web services description language (WSDL), and universal description, discovery, and integration (UDDI) in Perl. This is largely based on the SOAP Lite library, a typical example of the strength of Perl libraries for hiding the underlying complexities of network access and XML usage. Again, both client and server examples are given, and lots of variations on a simple task are presented, which offers a good way to build on basic functionality and to present other options. Like many OReilly books, this one is example oriented, rather than definitional in nature. This means that rather than presenting a more complete formal model and definitions of how such systems work, the authors build from incremental small examples, and demonstrate concepts through examples in Perl code.

The last third of the book is made up of appendices, including library references and all of the code to for the main examples. This does make it more self-contained, but I think such material is better placed on a Web site for search and download capabilities. Overall, if you use Perl, this is a great introduction to Web Services and their definition and usage.