Riff n. (in popular music and jazz) A short repeated phrase, frequently played over changing chords or used as a background to a solo improvisation.
Like a riff is a building block of jazz music, a Riff is the building block of the Djam admin. Riffs are essentially modular, decoupled chunks of namespaced functionality which can be attached to the main admin site. ModelAdmins (and the Django admin site) work on the same principle. The main difference in djam is that riffs don’t necessarily map one-to-one to models. There can be multiple registered riffs related to the same model, and there can be riffs registered which don’t relate to any model at all.
We’ll start out with ModelRiffs, which are essentially analogous to ModelAdmins. Here is how you could set up some basic ModelRiffs:
# myapp/riffs.py from djam.riffs.models import ModelRiff from myapp.models import MyModel, MyOtherModel class MyModelRiff(ModelRiff): model = MyModel class MyModelRiff2(ModelRiff): model = MyModel namespace = 'myapp_mymodel2' display_name = 'MyModel 2' slug = 'mymodel-2' class MyOtherModelRiff(ModelRiff): model = MyOtherModel use_modeladmin = False # Djam looks for this variable during :func:`.autodiscovery <autodiscover>`. riffs = [MyModelRiff, MyOtherModelRiff]
Each ModelRiff class has an associated model. If a ModelAdmin has been registered for that model, the riff will by default inherit a number of options from that ModelAdmin, unless use_modeladmin is False.
djam.autodiscover() loops through INSTALLED_APPS and loads any riffs.py modules in those apps - similar to the django admin’s autodiscovery.
On top of that, djam will by default include ModelRiffs which have been auto-generated from registered ModelAdmins. This can be turned of by passing in with_modeladmins=False.
For some commonly-used models (such as django.contrib.auth.User) djam provides a Riff which handles some functionality that would otherwise be lost during the conversion from ModelAdmin to ModelRiff. This can be disabled by passing in with_batteries=False.
The order that these are loaded is: app riff modules, “batteries”, and ModelAdmins. If two riffs are registered using the same namespace, the first one registered will take precedence; any others will be ignored.