LoginRequiredMixin and PermissionRequiredMixin could use UserPassesTestMixin

[Jaap Roes]

Currently ​django.contrib.auth.mixins defines LoginRequiredMixin and PermissionRequiredMixin as subclasses of AccessMixin.

It also defines an abstract UserPassesTestMixin that requires an implementation of test_func (or get_test_func).
Both LoginRequiredMixin and PermissionRequiredMixin perform tests on the current user and could be implemented subclasses of UserPassesTestMixin with an implementation of test_func (or get_test_func). That way they can re-use the dispatch logic in UserPassesTestMixin.

i.e.:

class LoginRequiredMixin(UserPassesTestMixin):
    def test_func(self):
        return self.request.user.is_authenticated


class PermissionRequiredMixin(UserPassesTestMixin):
    """Verify that the current user has all specified permissions."""
    permission_required = None

    def get_permission_required(self):
        """
        Override this method to override the permission_required attribute.
        Must return an iterable.
        """
        if self.permission_required is None:
            raise ImproperlyConfigured(
                '{0} is missing the permission_required attribute. Define {0}.permission_required, or override '
                '{0}.get_permission_required().'.format(self.__class__.__name__)
            )
        if isinstance(self.permission_required, str):
            perms = (self.permission_required,)
        else:
            perms = self.permission_required
        return perms

    def has_permission(self):
        """
        Override this method to customize the way permissions are checked.
        """
        perms = self.get_permission_required()
        return self.request.user.has_perms(perms)

    def get_test_func(self):
        return self.has_permission

[Jerin Peter George]

I would like to write the related docs, but I wish to know whether my implementations are okay or not.

[Mariusz Felisiak]

Unfortunately, due to the way UserPassesTestMixin is implemented, you cannot stack them in your inheritance list, so LoginRequiredMixin/PermissionRequiredMixin cannot subclass it, see ​Stacking UserPassesTestMixin.

[Jaap Roes]

Oh wow, I didn't realize this was a known flaw in the design of UserPassesTestMixin, sorry for the noise.