Rapid Application Development with Mozilla

Matthew Morgan writes "Mozilla's strengths as an application platform often go unrecognized for lack of good documentation. Nigel McFarlane sets out to change that in Rapid Application Development with Mozilla. McFarlane describes his book as "a conceptual overview, reference, and tutorial" for building applications on the Mozilla platform. But does he have room for all three in one book?" Read on for Morgan's answer to that question. Rapid Application Development with Mozilla author Nigel McFarlane pages 770 publisher Prentice Hall PTR rating 7 reviewer Matthew Morgan ISBN 0131423436 summary A good overview and tutorial for building applications atop Mozilla, though not a comprehensive reference.

The Basics Rapid Application Development with Mozilla (hereafter RADM) centers on XUL, Mozilla's XML dialect for describing GUIs. Other Mozilla components, like XBL and RDF, are described mainly in terms of how they plug into XUL. Each chapter presents and explains a component, then shows it in action by using it in an example application (a web-page annotator) developed throughout the book. Chapter conclusions take the form of debugging hints; as McFarlane ruefully notes, most errors cause Mozilla to silently do nothing, making debugging a chore.

The first half of RADM covers basic XUL use -- the usual complement of widgets with CSS to style them and JavaScript to manipulate them. McFarlane does assume previous exposure to basic HTML, JavaScript, and CSS, but extensive experience isn't required. At each step McFarlane does a good job explaining what's similar to HTML (e.g. most DOM stuff) and what isn't (e.g. the layout model). A few components have no real analog in the HTML model, like Mozilla's command dispatch system, so they're presented from the ground up.

The Back End

The second half of the book leans more toward the back end: using RDF for registries and template data; piping data into XUL with overlays, templates, and XBL; using and implementing XPCOM components; and deploying applications built on Mozilla.

McFarlane's RDF tutorial is one of the best I've seen. He starts off on the right foot by introducing things in terms of a directed graph, with lots of examples and diagrams. Only after eighteen pages of that does he introduce the RDF/XML syntax. His explanation of RDF/XML is unusually lucid, quite a feat considering how hairy RDF/XML gets. (Disclaimer: I've had past experience with RDF, so I wasn't reading this as a beginner -- in other words, YMMV.)

In the succeeding chapters, RDF is applied within the various Mozilla arenas, like XUL overlays and package installation, where it's used to store config information. The centerpiece of RDF in Mozilla, though, is in its use to create data-driven XUL files through XUL templates.

The chapter on templates runs to sixty-plus pages, and it's worth it. McFarlane covers things I haven't seen covered anywhere else. For instance, he describes the algorithm the RDF query engine uses to evaluate queries, so that you can better understand what kind of queries you can construct. This is crucial information because the query syntax allows a lot of queries that are logically reasonable, but won't actually work.

This points to a strength of RADM: McFarlane doesn't hesitate to criticize Mozilla where necessary. Throughout the book, he flags incomplete features, buggy implementations, and other gotchas, such as security restrictions surrounding RDF that make it all but useless for remote scenarios.

(Incidentally, McFarlane explicitly disclaims coverage of Phoenix/Firebird/Firefox, sticking to Mozilla 1.4, but in practice everything I've tried has worked fine in Firefox 0.8.)

Two Out Of Three Ain't Bad

So, does RADM manage to accomplish its goals of being a conceptual overview, tutorial, and reference? I'd give it two out of three.

As a conceptual overview, RADM shines. McFarlane is at his best when comparing and contrasting closely related components, like overlays, templates, and XBL, all of which extend XUL but do it in different ways. I was left with a good picture of what can and can't be done in Mozilla.

As a tutorial, RADM is solidly useful. The example-application sections cover a surprisingly large amount of ground -- more than enough to get a developer new to Mozilla up and running. McFarlane chose a good subset to present as examples; still, all of his clear writing can't paper over the fact that Mozilla is really complicated, not just internally, but in the interface it presents to developers using it as a platform.

As a reference, RADM stumbles. The index is slim -- a mere eighteen pages after 752 pages of content -- which makes small chunks of information hard to find. This is mitigated by a detailed and well-organized table of contents. After a few weeks of use, I find myself turning to the contents first, and only trying the index if I have to.

Fundamentally, though, RADM isn't really a reference book, and definitely not a "quick reference." You'd be better off using a good site like XULPlanet for quick what-arguments-does-that-method-take checks, and reserving RADM for in-depth explanations.

Conclusion

RADM is published in Bruce Perens' Open Source Series at Prentice Hall under the Open Publication License. After a few months of letting the book sell on its own, they'll post the PDF of the entire book online. Is it worth buying in print? Given that it's more of a sit-down-and-read book than a quick-reference guide, I'd say so.

If you're considering Mozilla as a platform, I'd recommend RADM for its reasonable balance that shows Mozilla's strengths and weaknesses. If you're already sold on Mozilla and just want to wrap your head around it and start building an app on it, RADM is the book for you.

You can purchase Rapid Application Development with Mozilla from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page

Comments

This book is helping the porn/spyware industry...

[Random Guru 42]

I've heard through the grapevine that some spyware companies and porn sites are putting together XPIs containing spyware, to start catching Mozilla users like they have IE users in the past. With the growth in use of Moz, plus this book, it's a pretty smart decision on their part. But it does mean that people will now need to be more careful about what they're browsing with Mozilla.

I guess a browser stops being alternative when porn sites start peddling spyware through it. So at least on that, congrats to all us Moz developers, we're on the road to mainstream!