A simple Django app to add soft-delete functionality to desired models
Add soft-delete functionality to desired models.
Follow steps mentioned below to add soft-delete feature in any model of your django app.
pip install django-softdelete-it
Add soft_delete_it to your INSTALLED_APPS setting like this:
INSTALLED_APPS = [ ... 'soft_delete_it', ]
Import SoftDeleteModel from soft_delete_it app to your model file like this:
from soft_delete_it import SoftDeleteModel
- Inherit SoftDeleteModel class to your model class. It will add following features:
- objects manager’s behavior will change such that:
- delete() method which will soft delete instances
- will always return return only ‘non soft deleted’ objects
- hard_delete()` method to hard delete the objects
- all_objects manager:
- will always return both soft deleted and non soft deleted objects
- hard_delete() method to hard delete the objects
- only_deleted() method to return only soft deleted objects
- undelete() method to un-delete soft-deleted objects
from django.db import models from soft_delete_it.models import SoftDeleteModel class Author(SoftDeleteModel): name = models.CharField(max_length=50) dob = models.DateField() class Article(SoftDeleteModel): title = models.CharField(max_length=50) body = models.TextField(null=True) author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name='articles') Bob = Author.objects.create(name='bob', dob='2000-12-12') John = Author.objects.create(name='john', dob='1990-10-12') Author.objects.all() # return QuerySet with 2 objects Bob.delete() # Bob is soft-deleted Author.objects.all() # return QuerySet with 1 object, John Author.all_objects.all() # return QuerySet with 2 object, Bob and John Bob.undelete() # un-deletes Bob object Author.objects.all() # return QuerySet with 2 objects article1 = Article(title='Bob The Builder', body='') article1.author = Bob article1.save() Article.objects.all() # return QuerySet with 1 object, article1 Bob.delete() # soft-deletes both Bob and article1 as Article's author field is on_delete_cascade and it Inherits SoftDeleteModel
If you are implementing a new Manager for a model, simply inherit SoftDeleteManager as well along with other Managers.
- If you are implementing a new QuerySet for a model, you will need to do following:
- Inherit SoftDeleteQuerySet
- Write Manager inheriting SoftDeleteManager which defines soft-delete functionality in it’s __init__() method(as in the example) and override get_queryset() method(as in the example)
- Write model class inheriting SoftDeleteModel and uses above new defined Manager method(as in the example)
Example with QuerySet
Lets create a QuerySet for Article such that if no author is provided while creating a new article, one default author will be added in object.
#Creating a default author object first default_author = Author.objects.create(name='default') #Implementing QuerySet from soft_delete_it.models import SoftDeleteModel, SoftDeleteQuerySet, SoftDeleteManager class ArticleQuerySet(SoftDeleteQuerySet): def create(self, **kwargs): try: author = kwargs['author'] except KeyError: kwargs['author'] = Author.objects.get(name='default') article = super(ArticleQuerySet, self).create(**kwargs) return article class ArticleManager(SoftDeleteManager): def __init__(self, *args, **kwargs): self.deleted_also = kwargs.get('deleted_also', False) super(ArticleManager, self).__init__(*args, **kwargs) def get_queryset(self): '''return all unsoft-deleted objects''' if self.deleted_also: return ArticleQuerySet(self.model) return ArticleQuerySet(self.model).filter(deleted=None) class Article(SoftDeleteModel): title = models.CharField(max_length=50) body = models.TextField(null=True) author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name='articles') objects = ArticleManager.from_queryset(ArticleQuerySet)() all_objects = ArticleManager.from_queryset(ArticleQuerySet)(deleted_also=True)
How soft-deletion functionality is implemented:
- Create a new soft_delete app, whole code for soft-deletion functionality is implemented in its models.py file.
- An abstract SoftDeleteModel added which contains a deleted attribute which is a UUIDField. It will hold None for undeleted object and a new uuid4 for deleted objects.
- SoftDeleteQuerySet implemented to override default django’s delete method to soft-delete objects instead of hard deleting them.
- undelete(), hard_delete(), only_deleted() methods are implemented in same QuerySet class to provide extra features.
- SoftDeleteManger implemented to use above QuerySet by overriding get_queryset() method.
- QuerySet’s delete method is necessary to override to support bulk_delete feature.
- Call pre_delete and post_delete signals before and after the definition of above delete method.
- Use NestedObjects from django admin utils to soft-delete all related objects.
- Two managers, objects and all_objects to return undeleted, all objects are implemented.
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