Question

Is there a way of telling django that a model having a contenttypes GenericForeignKey can only point to models from a predefined list? For example, I have 4 models: A, B, C, D and a model X that holds a GenericForeignKey. Can I tell X that only A & B are allowed for the GenericForeignKey?

Answer 1

For example,
your apps are app and app2 and there are A, B models in app and there are C, D models in app2.
you want to see only app.A and app.B and app2.C

from django.db import models

class TaggedItem(models.Model):
    tag = models.SlugField()
    limit = models.Q(app_label = 'app', model = 'a') | models.Q(app_label = 'app', model = 'b') | models.Q(app_label = 'app2', model = 'c')
    content_type = models.ForeignKey(ContentType, limit_choices_to = limit)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

use limit_choices_to on ForeignKey.

check django docs for details and Q objects, app_label.
you need to write proper app_label and model. This is just code snippet

plus: I think you write wrong app_label. This can help you.

from django.contrib.contenttypes.models import ContentType
for c in ContentType.objects.all():
    print(c.app_label, c.model)