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django-clone
Create copies of a model instance with explicit control on how the instance should be duplicated (limiting fields or related objects copied) with unique field detection.
This solves the problem introduced by using instance.pk = None and instance.save() which results in copying more object state than required.
Features
- 100% test coverage.
- More control over how a model instance should be duplicated
- Multi Database support i.e Create duplicates on one or more databases.
- Restrict fields used for creating a duplicate instance.
- Detects unique fields and naively adds a suffix
copy {count}to each duplicate instance (for supported fields only). - Optionally differentiate between a duplicate instance and the original by appending a copy suffix to non unique fields (for supported fields only).
Table of Contents
- Installation
- Usage
- Compatibility
- Running locally
- Found a Bug?
- Contributors
✨
Installation
Run
pip install django-cloneUsage
Subclassing the CloneModel
CHANGE
from django.db import models
class MyModel(models.Model):
title = models.CharField(max_length=200)TO
from django.db import models
from model_clone.models import CloneModel
class MyModel(CloneModel):
title = models.CharField(max_length=200)Example
from django.db import models
from django.utils.translation import gettext_lazy as _
from model_clone.models import CloneModel
class TestModel(CloneModel):
title = models.CharField(max_length=200)
tags = models.ManyToManyField('Tags')
_clone_m2m_fields = ['tags']
class Tags(models.Model): # To enable cloning tags directly use `CloneModel` as shown above.
name = models.CharField(max_length=255)
def __str__(self):
return _(self.name)Using the CloneMixin
from django.db import models
from django.utils.translation import gettext_lazy as _
from model_clone import CloneMixin
class TestModel(CloneMixin, models.Model):
title = models.CharField(max_length=200)
tags = models.ManyToManyField('Tags')
_clone_m2m_fields = ['tags']
class Tags(models.Model): # To enable cloning tags directly use `CloneMixin` as shown above.
name = models.CharField(max_length=255)
def __str__(self):
return _(self.name)Duplicating a model instance
In [1]: test_obj = TestModel.objects.create(title='New')
In [2]: test_obj.pk
Out[2]: 1
In [3]: test_obj.title
Out[3]: 'New'
In [4]: test_obj.tags.create(name='men')
In [4]: test_obj.tags.create(name='women')
In [5]: test_obj.tags.all()
Out[5]: <QuerySet [<Tag: men>, <Tag: women>]>
In [6]: test_obj_clone = test_obj.make_clone()
In [7]: test_obj_clone.pk
Out[7]: 2
In [8]: test_obj_clone.title
Out[8]: 'New copy 1'
In [9]: test_obj_clone.tags.all()
Out[9]: <QuerySet [<Tag: men>, <Tag: women>]>
In [6]: test_obj_clone = test_obj.make_clone(attrs={'title': 'Updated title'})
In [7]: test_obj_clone.pk
Out[7]: 3
In [8]: test_obj_clone.title
Out[8]: 'Updated title'
In [9]: test_obj_clone.tags.all()
Out[9]: <QuerySet [<Tag: men>, <Tag: women>]>Bulk cloning a model
In [1]: test_obj = TestModel.objects.create(title='New')
In [2]: test_obj.pk
Out[2]: 1
In [3]: test_obj.title
Out[3]: 'New'
In [4]: test_obj.tags.create(name='men')
In [4]: test_obj.tags.create(name='women')
In [5]: test_obj.tags.all()
Out[5]: <QuerySet [<Tag: men>, <Tag: women>]>
In [6]: test_obj_clones = test_obj.bulk_clone(1000)
In [7]: len(test_obj_clones)
Out[7]: 1000
In [8]: test_obj_clone = test_obj_clones[0]
In [9]: test_obj_clone.pk
Out[9]: 2
In [10]: test_obj_clone.title
Out[10]: 'New copy 1'
In [11]: test_obj_clone.tags.all()
Out[11]: <QuerySet [<Tag: men>, <Tag: women>]>Multi database support
In [6]: test_obj_clone = test_obj.make_clone(using='replica') # Replicate test object to a different database.
In [7]: test_obj_clone.pk
Out[7]: 1
In [8]: test_obj_clone.title
Out[8]: 'New'
In [9]: test_obj_clone.tags.all()
Out[9]: <QuerySet [<Tag: men>, <Tag: women>]>
In [10]: test_obj_clone._state.db
Out[10]: 'replica'CloneMixin attributes
| Attribute | Description |
|---|---|
DUPLICATE_SUFFIX |
Suffix to append to duplicates (NOTE: This requires USE_DUPLICATE_SUFFIX_FOR_NON_UNIQUE_FIELDS to be enabled and supports string fields). |
USE_DUPLICATE_SUFFIX_FOR_NON_UNIQUE_FIELDS |
Enable appending the DUPLICATE_SUFFIX to new cloned instances. |
UNIQUE_DUPLICATE_SUFFIX |
Suffix to append to unique fields |
USE_UNIQUE_DUPLICATE_SUFFIX |
Enable appending the UNIQUE_DUPLICATE_SUFFIX to new cloned instances. |
MAX_UNIQUE_DUPLICATE_QUERY_ATTEMPTS |
The max query attempt while generating unique values for a case of unique conflicts. |
Explicit (include only these fields)
| Attribute | Description |
|---|---|
_clone_fields |
Restrict the list of fields to copy from the instance (By default: Copies all fields excluding auto-created/non editable model fields) |
_clone_m2m_fields |
Restricted Many to many fields (i.e Test.tags) |
_clone_m2o_or_o2m_fields |
Restricted Many to One/One to Many fields |
_clone_o2o_fields |
Restricted One to One fields |
Implicit (include all except these fields)
| Attribute | Description |
|---|---|
_clone_excluded_fields |
Excluded model fields. |
_clone_excluded_m2m_fields |
Excluded many to many fields. |
_clone_excluded_m2o_or_o2m_fields |
Excluded Many to One/One to Many fields. |
_clone_excluded_o2o_fields |
Excluded one to one fields. |
NOTE:
⚠️
- Ensure to either set
_clone_excluded_*or_clone_*. Using both would raise errors.
Creating clones without subclassing CloneMixin.
In [1]: from model_clone.utils import create_copy_of_instance
In [2]: test_obj = TestModel.objects.create(title='New')
In [3]: test_obj.pk
Out[3]: 1
In [4]: test_obj.title
Out[4]: 'New'
In [5]: test_obj.tags.create(name='men')
In [6]: test_obj.tags.create(name='women')
In [7]: test_obj.tags.all()
Out[7]: <QuerySet [<Tag: men>, <Tag: women>]>
In [8]: test_obj_clone = create_copy_of_instance(test_obj, attrs={'title': 'Updated title'})
In [9]: test_obj_clone.pk
Out[9]: 2
In [10]: test_obj_clone.title
Out[10]: 'Updated title'
In [11]: test_obj_clone.tags.all()
Out[11]: <QuerySet []>NOTE:
⚠️
- This method won't copy over related objects like Many to Many/One to Many relationships.
- Ensure that required fields skipped from being cloned are passed in using the
attrskwargs.
Django Admin
Duplicating Models from the Django Admin view.
Change
from django.contrib import admin
from django.contrib.admin import ModelAdmin
@admin.register(TestModel)
class TestModelAdmin(ModelAdmin):
passto
from django.contrib import admin
from model_clone import CloneModelAdmin
@admin.register(TestModel)
class TestModelAdmin(CloneModelAdmin):
passList View
Change View
CloneModelAdmin class attributes
from model_clone import CloneModelAdmin
@admin.register(TestModel)
class TestModelAdmin(CloneModelAdmin):
# Enables/Disables the Duplicate action in the List view (Defaults to True)
include_duplicate_action = True
# Enables/Disables the Duplicate action in the Change view (Defaults to True)
include_duplicate_object_link = TrueNOTE:
⚠️
- Ensure that
model_cloneis placed beforedjango.contrib.admin
INSTALLED_APPS = [
'model_clone',
'django.contrib.admin',
'...',
]Signals
pre_clone_save, post_clone_save
from django.dispatch import receiver
from django.utils import timezone
from model_clone.signals import post_clone_save, pre_clone_save
from sample.models import Edition
@receiver(pre_clone_save, sender=Edition)
def increase_seq(sender, instance, **kwargs):
instance.seq += 1
@receiver(post_clone_save, sender=Edition)
def update_book_published_at(sender, instance, **kwargs):
if instance.book:
instance.book.published_at = timezone.now()
instance.book.save(update_fields=["published_at"])Compatibility
| Python | Supported version |
|---|---|
| Python2.x | <=2.5.3 |
| Python3.5 | <=2.9.6 |
| Python3.6+ | All versions |
| Django | Supported version |
|---|---|
| 1.11 | <=2.7.2 |
| 2.x | All versions |
| 3.x | All versions |
Running locally
$ git clone [email protected]:tj-django/django-clone.git
$ make default-user
$ make runSpins up a django server running the demo app.
Visit http://127.0.0.1:8000
Found a Bug?
To file a bug or submit a patch, please head over to django-clone on github.
If you feel generous and want to show some extra appreciation:
Support me with a
Contributors ✨
Thanks goes to these wonderful people:
 Gerben Neven |
 Sebastian Kapunkt |
 Andrés Portillo |
 WhiteSource Renovate |
 Yuekui |
 Take Weiland |
 Patrick |
 Amiel Kollek |
 Eric Theise |
This project follows the all-contributors specification. Contributions of any kind welcome!