Thursday, May 15, 2008

Python on web - getting started : selecting the tools

Why am i writing this? Well, because i felt that there are so many options, it is difficult to select an option for yourself. I was confused for quite some time in terms of what framework to use, what templating engine to use, which ORM layer to use and how to deploy the app on the web.

First of all, lets start of with the framework. The major frameworks are Django, TurboGears and pylons. Django is supposed to be the best framework from among the three. But Django is very tightly integrated to its template engine and ORM layer. And any sort of customization is not only difficult but also slows down the app. But it is good thing to start off python-on-web as a beginer. And its tight integration also accounts for its speed. It is the fastest framework among all of them. Take a look at some of the benchmarks on web here And

Django is a good framework to use if you are building a small site with default settings. But when you need to have an enterprise level site with customizations, it is better to use something like Turbogears or Pylons. Turbogears is good and has "Turbogears Widgets" but it lacks proper documentation. TurboGears uses CherryPy whereas Pylons uses paste. I felt pylons to be much easier to use and easier to configure. Pylons has a very small base though it is not as fast as Django. There are lots of comparisons available on the net - just google for it. gives a detailed comparison of different features of all the 3 frameworks.

After selecting Pylons as my framework, i have tons of options with respect to templating engine. I can use the default mako or kid or genshi or Cheetah (complete list available at I took a look on the performance benchmark and ease of use of all of them (from googlebaba ofcourse). And what i could figure out was that mako is the fastest template engine available. Genshi is a successor of kid and has a very clean xml-based integration. Which means that if i am using genshi, the html designer would not be able to see the code embedded within templates. So, i would prefer to use Mako or Genshi depending on the requirements. A list of different types of available template engines can be obtained from Benchmarks are available here Changing template engine for pylons is described here

I did not do any DB operations, so i did not go into selecting the ORM layer. Anyways, i always prefer to write my own queries instead of letting the ORM layer decide what query to fire. SQLAlchemy seems good though if you plan to use an ORM layer. SQLObject is also there, but it is old.

For deployment few options available are mod_wsgi, mod_python and the default paster. The paster server comes integrated with pylons and ofcourse cannot be used for production level deployment. mod_wsgi looked easy to use and is also supposed to be a small bit faster than mod_python. You can look at for mod_python or or mod_wsgi integration.

Next we would look at building and deploying the "hello world" application

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