Question

I have a simple class that includes a GenericRelation

class Item(models.Model):
    name  = models.CharField ( max_length=50, null=True, blank=True )
    image = generic.GenericRelation(Image)

class Image(models.Model):
    file  = models.FileField()
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

To make a copy of an Item I can set Item.id = None and save:

item = Item.objects.get(id=3)
item.id = None
item.save()
# item is now a copy of the original item

Unfortunately this doesn’t copy the image field to the new instance.

I tried manually copying it over:

item = Item.objects.get(id=3)
images = item.image.all()
item.id = None
item.save()
item.image = images

However this removes the images from the original instance, effectively moving them to the second instance instead of copying.

What’s a good way to copy the images over to the new instance?

Answer 1

To answer my own question: I ended up manually making a copy of the image and setting its object_id:

item = Item.objects.get(id=3)
image = item.image.all()[0]

image.id = None
image.object_id = new_item.id
image.save()