Turtles all the way down
(pronounced "djing", with a mostly-silent "d")
Blog entry: http://simonwillison.net/2009/May/19/djng/ Mailing list: http://groups.google.com/group/djng
djng is a micro-framework that depends on a macro-framework (Django).
My definition of a micro-framework: something that lets you create an entire Python web application in a single module:
def index(request): return djng.Response('Hello, world')
if name == 'main': djng.serve(index, '0.0.0.0', 8888)
Or if you want hello and goodbye URLs, and a custom 404 page:
app = djng.ErrorWrapper( djng.Router( (r'^hello$', lambda request: djng.Response('Hello, world')), (r'^goodbye$', lambda request: djng.Response('Goodbye, world')), ), custom_404 = lambda request: djng.Response('404 error', status=404), custom_500 = lambda request: djng.Response('500 error', status=500) )
if name == 'main': djng.serve(app, '0.0.0.0', 8888)
Under the hood, djng will re-use large amounts of functionality from Django, while re-imagining various aspects of the framework. A djng request object is a Django HttpRequest object; a djng response object is a Django HttpResponse. Django's template language and ORM will be available. Ideally, Django code will run almost entirely unmodified under djng, and vice versa.
I dislike Django's settings.py file - I often find I want to reconfigure settings at run-time, and I'm not comfortable with having arbitrary settings for so many different aspects of the framework.
djng experiments with /services/ in place of settings. Services are bits of shared functionality that djng makes available to applications - for example, caching, templating, ORM-ing and mail-sending.
Most of the stuff that Django sets up in settings.py will in djng be set up by configuring services. These services will be designed to be reconfigured at run-time, using a mechanism similar to Django middleware.
Some things that live in settings.py that really don't belong there - middleware for example. These will generally be constructed by composing together a djng application in code.
I'm still figuring out how the syntax for services should work.