CODEWITHSUNDEEP
pythonpython-3.xdjangodjango-models
Sarius
Sarius

Reputation: 145

Dynamic inheritance from Model

I have a Photo-Model that helps me achieve storing each image as a thumbnail aswell:

class Photo(models.Model):
    image = models.ImageField(upload_to=upload_path, default=default_image)
    thumbnail = models.ImageField(upload_to=upload_path_2, editable=False, default=default_image_2)
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

    class Meta:
        abstract = True

Now I have another Model, lets call it User, which inherits from Photo:

class User(Photo):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

Now lets say there are multiple classes inheriting from Photo and depending on the inheriting class, I want to set another upload_path and default_image. How Do I achieve that? Can I somehow use the constructor?

Thanks in Advance!

Upvotes: 1

Views: 75

Answers (1)

Exelian
Exelian

Reputation: 5888

I'd say that the best way to handle your use-case is slightly different. You can pass a function to upload_to. This function will be provided the signature instance and filename of the uploaded file (docs).

You can check class of the instance with isinstance or something similar and change the output accordingly.

def upload_path(instance, filename):
    if isinstance(instance, User):
        return 'user_{0}/{1}'.format(instance.user.id, filename)
    return 'photo/{1}'.format(filename)

Doing the same for default is a little bit harder. The default function won't be passed any reference to the model or field which will make it harder to override it based on model. You could simply add an image field to each of the concrete models, but I don't know if that would be appropriate.

Upvotes: 1

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