Converting Subnet to CIDR in Python

A nice recipe, here is the meat of an even faster version in the comments.

def calcDottedNetmask(mask):
    bits = 0xffffffff ^ (1 << 32 - mask) - 1
    return inet_ntoa(pack('>I', bits))

Which also led me to the Python netaddr project. Very cool!

Rundown on Django 1.0 Upgrade Problems (and Solutions)

I've been too swamped with my teaching lately to make much progress on a little app I initially wrote in 0.96.2 and have been trying to port to 1.0.

Besides some bonehead typos that wasted a lot of time, here are the summary of issues I've run across:

1. Creation of the new admin.py
2. Modifications of urls.py
3. Conversion between max_length and maxlength in your modles

I still don't have my admin interfaces working even though I've followed the exact steps, so I'm sure it is something else.

The main problems related to the admin interface, but there are a number of resources I've run across including Porting your apps from Django 0.96 to 1.0 and the complete list of backward incompatible changes and a conversion script to create the new admin interface conversion.

And how easy is Django CSV?

I'm a few hours (and of course I already have a functional app) into converting a spreadsheet "database" we currently store on Sharepoint with a Django app and I was pleased to see how easy it was to do CSV dumps of data. And it worked on the first time. Amazing.

And CherryPy Looks to be the Winner

So I've been looking for a pure Python lightweight HTTP server for serving up a small django app.

Here are the steps I used (assuming Django is already installed however you installed it) for Ubuntu Hardy LTS:

1) Install CherryPy 3.x (I installed the python-cherrypy3 package)

2) Get DjangoCerise and follow the docs. Documentation and these wrapper scripts were the make or break difference.

3) Increase number of threads in th e SERVER_THREADS file. My crude app worked fine but the django admin interface was a bit sluggish.

While it properly daemonizes (possibly because I screwed up the scripts) shutdown wasn't working for me and (quite obviously, in hindsight) unless you run the startup scripts as root (which I will be) once this app qoes into "production" it won't properly set the user to nobody.

From Aspen to Karrigell and web.py

Been struggling to get Aspen working with Django. My app works fine, still having issues with "static" apps, which are necessary for the media directory and I ran across two framworks I hadn't seen before.

The first was Karrigell

Karrigell is a flexible Python web framework, with a clear and intuitive syntax. It is independant from any database, ORM or templating engine, and lets the programmer choose between a variety of coding styles

The package includes a powerful built-in web server, so there's no need to download, install and configure a separate one, and a pure-Python database engine, PyDbLite, which is used for the demos

and another was web.py which is so barebones it is not worth quoting the website.

I doubt I'll use either of these, in particular I'm not sure the point of using a web framework unless there is an ORM?

No Model Inheritence in Django?

Based on this wiki page on Model Inheritance and this hack on extending models (yuck) not looking too good. I would guess this "just works" in Rails, since I've just redesigned my database now would be the time to switch but I really want Django's admin interface.

Not Too Happy with Django Migration

So after playing around with dmigration and dbmigration I'm probably going back to mucking with SQL (which I'm even less happy) or maybe hacking something together that meets my needs and actually works.