Opinionated Frameworks

Once again my post about Jinja and the Django template engine appeared on reddit. The second time in the last two weeks, probably because my feeds changed and planets re-displayed it.

I originally wrote the post a few months ago to promote Jinja a bit. I was and still am very happy with Jinja2 and wanted to write some lines about what I like about it and how it works. And I also was hoping that the Django guys have a look at it and copy some features of it. Mainly because every once in a while I contribute code to a Django powered project or have my fingers in some way in such a project's code. And every time I'm kinda puzzled how simple some really complex tasks in Django are.

So what has changed in Django's templates the last four months? Not that much. The only changes in the Django template engine was the addition of {% empty %} blocks in {% for %} loops (which does exactly what Jinja's {% else %} does for loops) and some bug fixing. Is that a problem? I don't know, but probably not.

Django's templates are still slow and limited as they were, but it's not causing problems so that users have to switch. Every once in a while I notice that people switch to Jinja from Django templates because of performance of the limitations, but very often they throw away half the framework because they discover that Python has more to offer than just Django. And with that in mind I guess the Django guys are doing the right thing.

Django is designed for content driven websites not so much for independently deployed applications (like trac, WordPress, MediaWiki and others). So not so much for applications and also not so much for stuff where you need crazy database queries that are not possible with Django. The template engine is designed for simple HTML generation and that's it. If you want more, you often want something different than Django anyways.

I know many successful projects that are running Django without problems and it works out for them, because their requirements match (nearly) exactly what the framework was developed for. And I know many that adopted Django because of the fuzz but what they actually want to do does not fit into the Django style of development.

In many ways Django reminds me a bit of unpacking cool stuff. You download it and are instantly blown away how cool it is. Database just works, templating is awesome, URL routing gives you these incredible neat looking URLs and much more. It's so cool that many are trying to suddenly do everything with it. And that's kinda where the problem lays. You are forcing Django to do things it's not designed for.

I think what is missing is a website that explains the advantages and disadvantages of the particular solutions and what projects work best with what solution. There are Pylons, Werkzeug, Paste, Repoze and a lot more frameworks and utility libraries that focus on different kinds of web applications. And that does not only apply to full blown frameworks or WSGI utilities, but also template engines, database libraries and even databases themselves. It would prevent a lot of frustration if people could find the framework or toolchain of choice before they start developing their project.

But such a page would have to be designed by someone unbiased. And neither me, nor anyone else who develops on/for a Python powered framework should create such a comparison page. But I would encourage everybody with experiences in multiple frameworks to write down their experiences with different Python frameworks, template engines, database adapters and combinations thereof.

Update: Fixed misleading sentence. Swapped complex and simple.