django-clone 5.2.0

Create a clone of a django model instance.

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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
  • Subclassing the CloneModel
  • Using the CloneMixin
  • Duplicating a model instance
    • Bulk cloning a model
    • Multi database support
  • CloneMixin attributes
    • Explicit (include only these fields)
    • Implicit (include all except these fields)
  • Creating clones without subclassing CloneMixin.
  • Django Admin
    • Duplicating Models from the Django Admin view.
      • List View
      • Change View
    • CloneModelAdmin class attributes
  • Signals
    • pre_clone_save, post_clone_save
• Compatibility
• Running locally
• Found a Bug?
• Contributors ✨

Installation

Run

pip install django-clone

Usage

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: :warning:

• 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: :warning:

• 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 attrs kwargs.

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):
    pass

to

from django.contrib import admin
from model_clone import CloneModelAdmin

@admin.register(TestModel)
class TestModelAdmin(CloneModelAdmin):
    pass

List 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 = True

NOTE: :warning:

• Ensure that model_clone is placed before django.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 [e-mail]:tj-django/django-clone.git
$ make default-user
$ make run

Spins 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 :star:

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!