How to make Django admin site accessed by non-staff user?

Question

Hello all,

I would like to implement a 2nd admin site which provides a subset of feature of the primary admin site. That's possible and described in the Django docs

However, I would like to limit access on the primary admin site. Some users can access the 2ndary site but not the primary site.

In order to implement that feature, I would like these users no to be in the staff (is_staff=False) and rewrite the AdminSite.has_permission

class SecondaryAdminSite(AdminSite):

    def has_permission(self, request):
        if request.user.is_anonymous:
            try:
                username = request.POST['username']
                password = request.POST['password']
            except KeyError:
                return False
            try:
                user = User.objects.get(username = username)
                if user.check_password(password):
                    return user.has_perm('app.change_onlythistable')
                else:
                    return False
            except User.DoesNotExist:
                return False
        else:
            return request.user.has_perm('app.change_onlythistable')

Unfortunately, this approach doesn't work. The user can login but can't see anything in the secondary admin site.

What's wrong with this approach? Any idea how to implement this feature?

Thanks in advance