Saturday, January 24, 2009

Book review: "Pro Django" by Marty Alchin

I volunteered to write a book review for Apress and I chose "Pro Django" by Marty Alchin (of course, I received the book for free at that point). Here's my review:

If you are serious about developing Web applications in Django, then "Pro Django" will be a great addition to your technical library. Note, however, that the "Pro" in the title really means "professional", "in-depth", at times even "obscure" -- so please, do not pick up this book if you're just starting out with Django. To really get the most out of this book, you need to already have at least one, and preferably several Django applications under your belt.

I personally just finished a small fun project for my daughter's 8th grade Science Fair: a Web site written of course in Django where her friends can take a fun science-related quiz and see if they improve their score the second time around, after being told the correct answer for each question. It was my first Django application, and I used the online documentation and tutorial (both very good), as well as the online Django book. I also used Sams' "Teach yourself Django in 24 hours" by Brad Dayley, which was very helpful for a beginner like me.

I say all this because in reading "Pro Django", you need to be already familiar with the core concepts of Django: models, views, templates, forms, and the all-important URL configuration. You won't get a feel for these concepts unless you actually start writing a Web application and understand the hard way how everything fits together. Once you have this understanding, and if you want to continue on the path of creating more Django apps, it's time for you to pick up "Pro Django".

Marty Alchin doesn't waste time delving into aspects of Python which are typically not used to their full potential by many people (including me): metaclasses, introspection, decorators, descriptors. In fact, the themes of introspection, customization and extension (which all take advantage of the dynamic nature of Python) keep coming up in almost every chapter of the book.

For example, the 'Models' chapter shows how to subclass model fields and how the use of metaclasses allows a field to know its name, and the class it was assigned to. The chapter also talks about the nifty technique of creating models dynamically at runtime. The 'URLs and Views' chapter goes into the gory details of the Django URL configuration mechanism, and shows how to use decorators to make views as generic as possible.

My favorite chapter was 'Handling HTTP'. It exemplifies what for me is the best part about Alchin's book: showing readers where and how to insert their own advanced processing code into the hooks provided by Django, without disturbing the flow of the framework. This is typically one of the hard parts of learning a Web framework, and Marty Alchin does a great job of explaining how to achieve a maximum of effect with a minimum of effort in this area, for example by writing your own middleware modules and inserting them into Django.

I also liked the last two chapters, 'Coordinating applications' and 'Enhancing applications', which show practical examples of code aggregated in mini-applications. In fact, this is also the main gripe I have about this book: I wish the author used more mini-applications throughout the book to explain the advanced concepts he described. He did show code snippets for each concept, but they were all isolated, and sometimes hard to place into the context of an application. I realize that space was limited, but it would have been so much nicer to see a real application being built and described throughout the book, with more and more functionality added at each stage.

Overall, I really enjoyed reading "Pro Django". However, reading such a book is just a start. What I really need to do is to start writing code and applying some of the new techniques I learned. I can't wait to do it!


Paul Hildebrandt said...

Nice Review! If I get another Django project I will probably pick up a copy.

Paul Hildebrandt said...

Nice Review!

If I get another Django project I will probably pick up a copy.

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