Important Shock

Worse is Better: Python templating systems vs. Rails ERb

(Disclaimer: Python is my favorite programming language; however, I do criticize it in this article. Please redirect flames to /dev/null.)

I’ve been comparing web frameworks lately, developing a relatively simple CRUD database-backed application that can support a few bells and whistles. I’ve checked out Ruby on Rails (who hasn’t?) Django, and Turbogears in my search, and realized something as I was hacking together some templates in Kid:

Python, a far more restrictive and inflexible language – one that would seem, on the surface, to be worse for web application development than Ruby – is better for programmers, designers and security by nature of its inflexibility.

Let me explain what I mean. When designing ‘views’ – the web pages that users will see – that need to be updated with data from a given database, it is natural to break the Model-View-Controller paradigm and embed some controller logic into the application. After all, it’s so much less effort to embed

<% found_books = Book.find_all(“title = ?”, given_title) %>

into your .rhtml files then to go back into the controller file, change the return types, and make sure everything works correctly. However, Python is whitespace-sensitive, and therefore is much more difficult to embed into HTML. As such, you can’t write the mixture of Ruby and HTML that makes Rails so easy to use.

This is a good thing. I am a strong advocate of separating the model, view, and controller; by the very fact that I can’t write a combination of Python and HTML, I am forced to go back into the CherryPy/Django controller codebase and write a properly formed, secure, and elegant SQL query. Normally laxity wouldn’t bother me, but I believe that any large web application will grow into a hideous, Nylartothepic tangle if the MVC rules are not followed to the letter.

I still love Rails, but I love the templating systems in Python even more. Because Python is so restrictive, people had to write templating systems the Right Way – and that’s a good thing for everybody.