poulpe/event/signals.py

from django.dispatch import receiver
from django.db.models.signals import post_save
from django.apps import apps
from django.contrib.contenttypes.models import ContentType
from django.contrib.auth.models import Permission
from event.models import Event, EventGroup
from guardian.shortcuts import assign_perm


@receiver(post_save, sender=Event)
def create_groups_for_event(sender, **kwargs):
    event, created = kwargs["instance"], kwargs["created"]
    if created:
        orgas = EventGroup.objects.create(
            name="{}_orgas".format(event.slug),
            event=event
        )

        # Models having event-specific permissions
        models = [model for model in apps.get_models()
                  if getattr(model, 'needs_event_permissions', False)]

        for model in models:

            for perm in Permission.objects.filter(
                content_type=ContentType.objects.get_for_model(model)
            ):
                print(perm.codename)
                assign_perm(perm.codename, orgas, event)

        EventGroup.objects.create(
            name="{}_participants".format(event.slug),
            event=event,
        )