django-cancan 0.2

Authorization library for Django

django-cancan

django-cancan is an authorization library for Django. It works on top of default Django permissions and allows to restrict the resources (models and objects) a given user can access.

This library is inspired by cancancan for Ruby on Rails.

Quick start

1. Add cancan to your INSTALLED_APPS setting like this:

INSTALLED_APPS = [
    ...,
    'cancan',
]

2. Create a function that define user abilites. For example, in abilities.py:

def declare_abilities(user, ability):
    if not user.is_authenticated:
        # Allow anonymous users to view published articles
        return ability.can('view', Article, published=True)

    if user.has_perm('article.view_own_article'):
        # Allow logged in user to change his articles
        return ability.can('change', Article, author=user)

    if user.is_superuser:
        # Allow superuser change all articles
        return ability.can('change', Article)

3. Configure cancan by adding CANCAN section in settings.py:

CANCAN = {
    'ABILITIES': 'myapp.abilities.declare_abilities'
}

Next, add cancan middleware after AuthenticationMiddleware:

MIDDLEWARE = [
    ...
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'cancan.middleware.CanCanMiddleware',
    ...
]

Adding the middleware adds request.ability instance which you can use to check for: model permissions, object permissions and model querysets.

4. Check abilities in views:

class ArticleListView(ListView):
    model = Article

    def get_queryset():
        # this is how you can retrieve all objects a user can access
        qs = self.request.ability.queryset_for('view', Article)
        return qs


class ArticleDetailView(PermissionRequiredMixin, DetailView):
    queryset = Article.objects.all()

    def has_permission(self):
        article = self.get_object()
        # this is how you can check if user can access an object
        return self.request.ability.can('view', article)

Testing

Run ./manage.py test to run all test for the testapp