django-snapshot-field 0.1.5

A field in a model that store a snapshot of a model object and retrieves it as a read-only model object

A field in a model that stores a snapshot of a model object and retrieves it as a read-only model object

Installation

pip install django-snapshot-field

or from git

pip install -e git+https://githib.com/Apkawa/django-snapshot-field.git#egg=django-snapshot-field

Django and python version compatibles

Python Django	3.8	3.9	3.10	3.11	3.12	3.13
4.2	✅	✅	✅	✅	✅	✅
5.0	❌	❌	✅	✅	✅	✅
5.1	❌	❌	✅	✅	✅	✅
5.2	❌	❌	✅	✅	✅	✅

Usage

from django.db import models
from snapshot_field.fields import SnapshotModelField

class Example(models.Model):
    name = models.CharField(max_length=20)

class ExampleReference(models.Model):
    name = models.CharField(max_length=20)
    ref = models.ForeignKey(Example)


class ExampleSnapshotModel(models.Model):
    snapshot = SnapshotModelField(null=True)
    snapshot_refs = SnapshotModelField(
        ['tests.Example', ['ExampleReference', {'fields': ['name', 'ref'], 'refs': ['ref']}]]
    )


obj = Example.objects.create(name='test_name')
obj_ref = ExampleReference.objects.create(name='refname', ref=obj)

snap = ExampleSnapshotModel.objects.create(snapshot=obj, snapshot_refs=obj_ref)

assert snap.snapshot.name == obj.name
assert snap.snapshot_refs.name == obj_ref.name
assert snap.snapshot_refs.ref.name == obj.name

obj.delete()
obj_ref.delete()
snap.refresh_from_db()

assert snap.snapshot.name == obj.name
assert snap.snapshot_refs.name == obj_ref.name
assert snap.snapshot_refs.ref.name == obj.name