Django Guardian Groups w/ Django ORM's Model Save Events

base.py

from django.contrib.auth.models import Group
from django.db import models
from django.db.models.signals import post_save, pre_save
from django.dispatch import receiver
from guardian.shortcuts import assign_perm


class EventModel(models.Model):

    class Meta:
        abstract = True

    def on_pre_save(self):
        pass

    def on_post_save(self, created):
        pass


@receiver(pre_save)
def signal_event_on_pre_save(sender, instance, **kwargs):
    if issubclass(sender, EventModel):
        instance.on_pre_save()


@receiver(post_save)
def signal_event_on_post_save(sender, instance, created, **kwargs):
    if issubclass(sender, EventModel):
        instance.on_post_save(created)


class GroupModel(EventModel):
    groups = {}

    class Meta:
        abstract = True

    def on_post_save(self, created):
        super().on_post_save(created)
        if created:
            self._make_groups()

    def get_group(self, name):
        group, _ = Group.objects.get_or_create(name=f'{self._meta.app_label}:{self._meta.model_name}:{self.pk}:{name}')
        return group

    def remove_from_groups(self, user):
        for name in self.groups:
            group = self.get_group(name)
            user.groups.remove(group)

    def _make_groups(self):
        for name in self.groups:
            group = self.get_group(name)
            for perm in self.groups[name]:
                assign_perm(perm, group, self)

organization.py

from django.conf import settings
from django.db import models
from django.utils.translation import ugettext as _
from guardian.models import UserObjectPermissionBase, GroupObjectPermissionBase

from project.models.base import GroupModel
from project.utils.fields import NonNaiveDateTimeField


class OrganizationManager(models.Manager):

    def get_by_natural_key(self, name):
        return self.get(name=name)


class Organization(GroupModel):
    objects = OrganizationManager()
    groups = {
        'admin': ['view_organization', 'change_organization', 'delete_organization'],
        'member': ['view_organization'],
        'public': ['view_organization_public'],
    }

    name = models.TextField(unique=True)
    address = models.TextField()
    city = models.TextField()
    state = models.TextField()
    zip_code = models.TextField()
    created = NonNaiveDateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        db_index=True,
        related_name='organizations_created',
        on_delete=models.SET_NULL,
        null=True,
    )

    def __str__(self):
        return f'{self.name}'

    class Meta:
        permissions = (
            ('view_organization', _('Can view organization')),
            ('view_organization_public', _('Can view organization public')),
        )
        ordering = ['id']

    def on_post_save(self, created):
        super().on_post_save(created)
        if created:
            self.created_by.groups.add(self.get_group('admin'))


class OrganizationUserObjectPermission(UserObjectPermissionBase):
    content_object = models.ForeignKey(Organization, on_delete=models.CASCADE)


class OrganizationGroupObjectPermission(GroupObjectPermissionBase):
    content_object = models.ForeignKey(Organization, on_delete=models.CASCADE)