Django snippets

from django.db.models.fields.files import FieldFile

def file_cleanup(sender, instance, *args, **kwargs):
    '''
        Deletes the file(s) associated with a model instance. The model
        is not saved after deletion of the file(s) since this is meant
        to be used with the pre_delete signal.
    '''
    for field_name, _ in instance.__dict__.iteritems():
        field = getattr(instance, field_name)
        if issubclass(field.__class__, FieldFile) and field.name:
            field.delete(save=False)

...

from django.db import models
from django.db.models.signals import pre_delete

class SomeModel(models.Model):
    ...
    my_file = models.FileField(upload_to='my_files')
    ...

# delete my_file when we delete an instance of SomeModel
pre_delete.connect(file_cleanup, sender=SomeModel)