Programming Web Services with Perl

ggoebel writes "Programming Web Services with Perl is principally a book on implementing solutions using XML-RPC and SOAP in Perl. It also covers complementary and alternative standards such as WSDL, UDDI, and REST in some detail. And on the periphery, it finishes with a whirlwind tour of developing message routing, alternative data encoding within XML, security, transactions, workflow, internationalization, service discovery, extension, and management techniques and specifications." Read on for ggoebel's full review.

Programming Web Services with Perl
author	Randy J. Ray, Pavel Kulchenko
pages	496
publisher	O'Reilly (December 2002)
rating	9 of 10
reviewer	ggoebel
ISBN	0596002068
summary	practical balanced guide to XML::RPC and SOAP::Lite

The book assumes the reader will have the knowledge of an intermediate level Perl programmer. I.e., the reader is assumed to have a working knowledge of references, data structures, and object-oriented Perl. On the other hand no previous knowledge of XML, XML-RPC, SOAP or XML related technologies is required.

It should also be mentioned that both of the authors Randy J. Ray and Pavel Kulchenko are also the principle developers of the most popular XML-RPC and SOAP Perl modules: XML::RPC and SOAP::Lite respectively. That said, the book is not a soap box for the authors to tout the merits of their tools.

Rather, it is a practical book which starts with grounding fundamentals. Readers should walk away with a core understanding of XML-RPC and SOAP and not just a particular tool set for working with them. The authors examine the alternative XML-RPC and SOAP tools, illustrate how they are used, and give practical and even handed reasons why their modules should be preferred. Which comes down to issues of features, active development, support, and the amount of work required to code to a particular interface. They then settle down to a comfortable and thorough guide to XML::RPC and SOAP::Lite.

The topics and issues are illustrated throughout using real world web services. For example creating an XML-RPC client for O'Reilly's Meerkat news wire, or a SOAP client to covert use.perl.org's journal stream to RSS. Code is presented to the reader filtered down to highlight each particular issue as it is discussed. This is nice in that it avoids listing slight variations of the same code multiple times, but on the down side it can also leave the reader flipping back and forth to reassemble an example in their head. Full code for each example is provided in the appendices. And all of the example code may be downloaded from O'Reilly.

All-in-all, the book is a thorough practical introduction to working with XML-RPC, SOAP and related technologies. When I started reading the book, I was a bit disappointed to see that it only covered XML-RPC and SOAP related services. When I finished, I was impressed with how very much information they'd managed to pack into so few pages.

And yet, I was left wishing there'd been a more through coverage of interoperability issues between other SOAP implementations and things like custom de-serializers. To be honest interoperability and de-serialization are mentioned, and the authors do an excellent job of referring the reader on to sources for continued reading on most other topics.

The book does an admirable job balancing content, length, and information density. Not to mention an excellent job delivering the information that will still be relevant years and not just weeks from the date published. Most of the topics I'd wished to see covered in more depth are those that are still developing and consequently most likely to become quickly dated. In short a well balanced practical guide to applying XML-RPC and SOAP to solve problems.

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Re:Web Services and Perl vs. Web Apps

[Black Perl]

For example, let us say I wanted to map a directory to a particular CGI script. If I were building CGI apps with Perl, I couldn't do that

What does that have to do with Perl? If you were building CGI apps with Java, you wouldn't be able to do that either. CGI != perl.

On the other hand, this can be easily accomplished by a developer building a Web App for a Java servlet container (like Tomcat) by specifying the mapping in the WEB-INF/web.xml of the web application he's building.

Playing along with this terrible web-server configuration example... You can easily do the same thing with mod_perl or PHP (which uses mod_PHP). A "servlet container", mod_perl, and mod_PHP are all types of web app server. Compare apples and apples.