Django delete unused media files
Question:
I have a django project in which the admins are able to upload media. As items sell, they are deleted from the site, thus removing their entry in the MySQL database. The images associated with the item, however, remain on the file system. This isn’t neccessarily bad behavior – I don’t mind keeping files around in case a deletion was an accident. The problem I forsee is two years from now, when storage space is limited because of a media folder bloated with old product images.
Does anyone know of a systematic/programmatic way to sort through ALL the images and compare them to the relevant MySQL fields, deleting any image which DOESN’T have a match from the filesystem? In the perfect world I’m imagining a button in the django-admin like “Clean-up unused media” which executes a python script capable of this behavior. I’ll be sharing whatever my eventual solution is here, but what I’m looking for right now is anyone who has ideas, knows resources, or has done this at some point themselves.
Answers:
You can use signals. Than use os.remove() to clean up related files on delete.
This way your file system always reflects you db. No need for hitting some button.
The following is how I currently do it with Django 1.7 which need to be used from the start I don’t know how you clean up unreferenced files in retrospect.
Say you’ve got an app named ‘cars’ and a model named ‘Car’.
signals.py:
# cars/signals.py
from django.conf import settings
from django.dispatch import receiver
from django.db.models.signals import post_delete
from cars.models import Car
# By adding 'Car' as 'sender' argument we only receive signals from that model
@receiver(post_delete, sender=Car)
def on_delete(sender, **kwargs):
instance = kwargs['instance']
# ref is the name of the field file of the Car model
# replace with name of your file field
instance.ref.delete(save=False)
apps.py:
# cars/apps.py
from django.apps import AppConfig
class CarConfig(AppConfig):
name = "cars"
def ready(self):
import cars.signals
__init__.py:
default_app_config = 'cars.apps.CarConfig'
Try django-cleanup, it automatically invokes delete method on FileField when you remove model.
pip install django-cleanup
settings.py
INSTALLED_APPS = (
...
'django_cleanup.apps.CleanupConfig', # should go after your apps
)
django-unused-media will help you to clean old unused media by management command.
Very useful when you just started to use django-cleanup and already have files which needs to be deleted.
Or if you have thumbnails which needs to be deleted from media directory.
Perhaps this is a bit late, but if you also want to know more about the problems that can appear with deletion, here’s an article which explains how to delete them in two ways (with code snippets).
There is a management command which can be called every now and then, and a more “immediate” solution, using signals.
I have a django project in which the admins are able to upload media. As items sell, they are deleted from the site, thus removing their entry in the MySQL database. The images associated with the item, however, remain on the file system. This isn’t neccessarily bad behavior – I don’t mind keeping files around in case a deletion was an accident. The problem I forsee is two years from now, when storage space is limited because of a media folder bloated with old product images.
Does anyone know of a systematic/programmatic way to sort through ALL the images and compare them to the relevant MySQL fields, deleting any image which DOESN’T have a match from the filesystem? In the perfect world I’m imagining a button in the django-admin like “Clean-up unused media” which executes a python script capable of this behavior. I’ll be sharing whatever my eventual solution is here, but what I’m looking for right now is anyone who has ideas, knows resources, or has done this at some point themselves.
You can use signals. Than use os.remove() to clean up related files on delete.
This way your file system always reflects you db. No need for hitting some button.
The following is how I currently do it with Django 1.7 which need to be used from the start I don’t know how you clean up unreferenced files in retrospect.
Say you’ve got an app named ‘cars’ and a model named ‘Car’.
signals.py:
# cars/signals.py
from django.conf import settings
from django.dispatch import receiver
from django.db.models.signals import post_delete
from cars.models import Car
# By adding 'Car' as 'sender' argument we only receive signals from that model
@receiver(post_delete, sender=Car)
def on_delete(sender, **kwargs):
instance = kwargs['instance']
# ref is the name of the field file of the Car model
# replace with name of your file field
instance.ref.delete(save=False)
apps.py:
# cars/apps.py
from django.apps import AppConfig
class CarConfig(AppConfig):
name = "cars"
def ready(self):
import cars.signals
__init__.py:
default_app_config = 'cars.apps.CarConfig'
Try django-cleanup, it automatically invokes delete method on FileField when you remove model.
pip install django-cleanup
settings.py
INSTALLED_APPS = (
...
'django_cleanup.apps.CleanupConfig', # should go after your apps
)
django-unused-media will help you to clean old unused media by management command.
Very useful when you just started to use django-cleanup and already have files which needs to be deleted.
Or if you have thumbnails which needs to be deleted from media directory.
Perhaps this is a bit late, but if you also want to know more about the problems that can appear with deletion, here’s an article which explains how to delete them in two ways (with code snippets).
There is a management command which can be called every now and then, and a more “immediate” solution, using signals.