python - How to use dynamic foreignkey in Django?

Question

I want to connect a single ForeignKey to two different models.

For example:

I have two models named Casts and Articles, and a third model, Faves, for favoriting either of the other models. How can I make the ForeignKey dynamic?

class Articles(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

class Casts(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()

class Faves(models.Model):
    post = models.ForeignKey(**---CASTS-OR-ARTICLES---**)
    user = models.ForeignKey(User,unique=True)

Is this possible?

Answer 1

Here is how I do it:

from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import fields


class Photo(models.Model):
    picture = models.ImageField(null=True, upload_to='./images/')
    caption = models.CharField(_("Optional caption"),max_length=100,null=True, blank=True)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = fields.GenericForeignKey('content_type', 'object_id')

class Article(models.Model):
    ....
    images     = fields.GenericRelation(Photo)

You would add something like

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = fields.GenericForeignKey('content_type', 'object_id')

to Faves and

    fields.GenericRelation(Faves)

to Article and Cast

contenttypes docs