Last autumn’s release of Pro Drupal Development was a significant moment in the history of the popular CMS, providing for the first time a relatively comprehensive guide for those wanting to do more than simply manage and skin a drupal site. A number of books have followed it but few have delved as deeply or been such a definitive guide.
Like most of the more recent books, Learning Drupal 6 Module Development focusses on a quite specific area of drupal development, but its a key one for any serious developer and touches every other area of the system. Experienced PHP developers may find that this book (in conjunction with some time for experimentation) will serve as a solid introduction to how they might build applications on top of drupal.
The book focusses on a single project—a website providing biographies of philosophers—and builds the modules it needs, introducing the various available tools and techniques along the way. Much of the time is devoted to generating custom content types, but there’s very solid coverage of the hooks, filters, and actions that let modules really take integrate with the rest of the framework. Theming your output, using AJAX, and working with web services all get some time and illustrate how your app can be part of the wider web and keep up with its prevailing trends. A number of times I found myself reaching for code I’d written over the past few months to make amendments based on examples in the book.
I’ve been quite critical of books from packt lately and some of my criticisms apply here—he book itself feels flimsy and the print quality is poor—but this is also evidence that if an author and editor put the work in they do occasionally produce quality material despite the publisher. There are a number of asides that clarify language which demonstrate an attention to detail too often missing. It would have been good to see clearer signposts as to which features are new in Drupal 6 and which were available previously, but the online API docs can provide most of that.
When I reviewed Pro Drupal Development I noted some disappointment that the book didn’t devote any time to automated testing of drupal code, and that criticism applies here too. Along with staged deployments, automated testing remains one of the least considered aspects of drupal and that’s a serious concern for those looking to build robust well-managed applications on top of it. There are a few good articles online about how to test drupal code, but it would be good to see it taken more seriously as a core part of the module development process.
This book is likely to sit alongside Pro Drupal Development on my desk whenever I’m working on a drupal project and is a worthwhile investment for anyone who spends much time building drupal modules. There are clear areas for improved coverage, but it is as comprehensive an account as you’ll find of how to build modules that take full advantage of the facilities Drupal provides.