What version of Python should I be using to develop web applications?

Question

Currently I have Python 3.1.1 installed on my system, same version on my server with WSGI 3.0 running on Apache 2.2.

I want to keep using Python 3.1, but I'm finding that lots of libraries/frameworks don't support it yet, namely Django, Pylons, MySQLdb, etc.

I also checked an account I have on a friend's server, and it is running Python 2.3.4...

I want to write a sort of blog/forum type application that I can expand into a CMS, and eventually write related desktop applications for, as sort of a long-term pet project.

I'd like to use the newest version of Python possible for best security and highest consistency with the desktop-applications-to-be, while still maintaining a good level of portability, and supporting most of the frameworks and libraries I will use.

But I'm lost on which one I should pick. It seems like 2.4 would have the greatest amount of portability but it's sort of old, and I don't want to wind up using a bunch of post-2.4 features that won't compile, and having to re-write with messier code to compensate for it. 2.6 would be better, but it seems like lots of libraries are still porting over to that, and 3.1 would be the best since it eliminates a lot of cruft from the language.

One thing I'd like to highlight is that it'd be nice to know what I will be missing if I choose an older version of Python. For example, if I were to need my application to run on my old Python 2.3.4 account on my friend's server, what libraries/features would I be lacking that exist in newer versions? What problems would I surely run into that would make me wish I was using Python 2.6 or 3.1? Which of these features would be available via __future__ imports?

So, what would be the best direction to go? Should I just use 2.6 and deal with any issues? Should I go for 2.4 to maximize my ability to possibly distribute it to shared hosting environments? Or should I just jump into 3.1 and have a slightly-crippled application until libraries like MySQLdb catch up?

Answer 1

Begin with Python 2.5 if you're not sure.

Have a look at Google App Engine (based on Django). It's using Python 2.5 and it's free. However, you will not be able to call scipy (for example) or any libraries with "C" inside.

You will have the greatest amount of portability with Python2.5. Moreover, python3k is not really used in the industry.

Answer 2

For now, Python 3 is not widely deployed in production. Depends on what you use Python for. If it's just for one off scripts, it will be ok either way, if the idea is to use third party modules, C modules and or deploy painlessly, then settle for any of the 2.4+ versions. Many projects strive to keep 2.3 compativility, but you shouldn't have any problems to use 2.4-2.6, as the changes in the language are minor. If you can, use 2.6, as it's the closest to Python 3, as it has some features backported to it.

The problem with Python 3 is a Catch 22:

• most useful third party modules are still not ported to 3, as developers are waiting for wide usage,
• people can't migrate because modules they rely on haven't migrated yet, keeping the sage low.

You should not have any problems using any of the 2.4-2.6, give 3, some time.

Use Python 2.6

Answer 3

"2.6 would be better, but it seems like lots of libraries are still porting over to that"

What? What libraries -- that you need -- are "still porting over to that"?

"3.1 would be the best" "but I'm finding that lots of libraries/frameworks don't support"

Correct. You've stated that twice in the question. That's very clear.

"Should I just use 2.6 and deal with any issues"

What issues? Do you have any specific concerns?

It seems to work really, really well. What are your specific concerns?

Answer 4

For intranet web apps I had to install python 2.5 (due to combination of wiki, bug tracker, and httpd WSGI compatibility). For custom web apps I standardized on python 3.2. Thus I have both installed simultaneously. I write for 3.2 and bring specific libraries up to spec as needed. However large packages which I don't want to modify use their own 2.5. Compatibility between 3.2 and 3rd party packages is still an issue at this time, and so is the lack of proper python recipes.

In summary: Install two versions.