Django模型中的Override Field属性

Question

I have a problem. I'm trying to change the directory on which a file gets uploaded, using the upload_to attribute of a FileField, without success.

The main issue is that I have defined a parent class, with a file attribute, and I want to change the directory on the child class.

My models are defined in this way :

class DocumentBase(models.Model):
    file = models.FileField(upload_to=get_filename)


class Document(DocumentBase):
    file_type = models.CharField(max_size=150)

I tried to overwrite the FileField in the child class, without success (I'm aware now that this is not possible.)

I also tried the answers on this other question (that is very similar to my problem), without success.

Could somebody help me with this? Thanks!

Answer 1

As Willem said this can be solved monkey patching the upload_to attribute. But it didn't work for this case.

Digging into the FileField class definition , this class has another attribute: generate_filename . This attribute is filled when upload_to is callable. This attribute is used to generate the file filename.

So, the solution that worked was :

class DocumentBase(models.Model):
    file = models.FileField(upload_to=get_filename)


class Document(DocumentBase):
    file_type = models.CharField(max_size=150)

Document._meta.get_field('file').generate_filename = other_get_filename

This behavior changes on Django 1.10.