Well, it turns out there's a very powerful feature baked into Django which can handle the task for us.

Django includes an internal "dispatcher" which allows objects to listen for signals from other objects.

In our case, our tumblelog app is going to "listen" to our Entry and Link models. Every time a new Entry or Link is saved, those models will send out a signal. When the tumblelog app gets the signal it will automatically update itself.

Link.objects.get_or_create( url = info['href'], description = info['extended'], tags = info.get('tag', ''), date = parsedate(info['time']), title = info['description']

But we don't want to have to log in to the shell every time we want to update our displayed list of bookmarks. In fact, we want our site to automatically update itself. To do that, we're going to write a quick python script and then run it through a cron job.

problem

Set DJANGO_SETTINGS_MODULE before you run

export DJANGO_SETTINGS_MODULE=yoursite.settings

# Cron jobs for foo.com run at 3AM DJANGO_SETTINGS_MODULE=foo.settings 0 3 * * * python /path/to/maintenance/script.py 30 3 * * * python /path/to/other/script.py # Cron jobs for bar.com run at 4AM DJANGO_SETTINGS_MODULE=bar.settings 0 4 * * * python /path/to/maintenance/script.py 30 4 * * * python /path/to/other/script.py

Django is a web framework written in Python. Pyjamas is a Python port of the google web toolkit (written in Java). Pyjamas can be used with Django to create web applications.

Django cheat sheet

Big list of Django tips

Writing managers is really simple, and they provide a better user interface to your code. This code snippet simply adds a latest() method to the default objects manager class ForecastDayManager(Manager): def __init__(self, *args, **kwargs): super(ForecastDayManager, self).__init__(*args, **kwargs) def latest(self): return self.get_query_set().order_by('forecast_date')[0] It can be called ForecastDay.objects.latest(). This is a trivial example, but there is a lot of power that lies in this functionality.

Every Django model class and every instance of every Django model class has an attribute on it named _meta