pcarn / django-softdelete

Soft delete for Django ORM, with support for undelete.

django-softdelete

Soft delete for Django ORM, with support for undelete. Supports Django 2.0+

This project provides undelete of soft-deleted objects, along with proper undeletion of related objects.

Inspired by http://codespatter.com/2009/07/01/django-model-manager-soft-delete-how-to-customize-admin/

Requirements

• Django 1.8+
• django.contrib.contenttypes

Installation

pip install django-softdelete

Configuration

There are simple templates files in templates/. You will need to add Django's egg loader to use the templates as is, that would look something like this:

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': '/path/to/my/templates',
        'OPTIONS': {
             'loaders': (
                  'django.template.loaders.filesystem.Loader',
                  'django.template.loaders.app_directories.Loader',
              ),
         }
    },
]

Add the project softdelete to your INSTALLED_APPS for through-the-web undelete support.

INSTALLED_APPS = (
...
    'django.contrib.contenttypes',
    'softdelete',
)

Usage

• Run django-admin migrate
• For the models that you want soft delete to be implemented in, inherit from the SoftDeleteObject with from softdelete.models import SoftDeleteObject. Something like MyCustomModel(SoftDeleteObject, models.Model). This will add an extra deleted_at field which will appear in the admin form after deleting/undeleting the object
• If you have a custom manager also make sure to inherit from the SoftDeleteManager.
• After that you can test it by deleting and undeleting objects from your models. Have fun undeleting :)

Settings

Name	Default	Description
SOFTDELETE_CASCADE_ALLOW_DELETE_ALL	True	Setting to confirm if the logic for deleting related entities should fall back to deleting all model entities in the event of an exception being raised when calling delete

How It Works

Central to the ability to undelete a soft-deleted model is the concept of changesets. When you soft-delete an object, any objects referencing it via a ForeignKey, ManyToManyField, or OneToOneField will also be soft-deleted. This mimics the traditional CASCADE behavior of a SQL DELETE.

When the soft-delete is performed, the system makes a ChangeSet object which tracks all affected objects of this delete request. Later, when an undelete is requested, this ChangeSet is referenced to do a cascading undelete.

If you are undeleting an object that was part of a ChangeSet, that entire ChangeSet is undeleted.

Once undeleted, the ChangeSet object is removed from the underlying database with a regular ("hard") delete.

Warnings

When using cascade delete, the default behaviour when the call to delete a related object raises an exception is to fallback to deleting all the entities for that model class from the database. You can prevent this behaviour by using the SOFTDELETE_CASCADE_ALLOW_DELETE_ALL setting. Set this to False to prevent the behaviour.

Testing

Can be tested directly with the following command:

django-admin.py test softdelete --settings="softdelete.settings"