django-handleref

track when an object was created or changed and allow querying based on time and versioning (w/ django-reversion support)

HandleRefModel as a base for all your models

from django.db import models
from django_handleref.models import HandleRefModel

class Test(HandleRefModel):
    name = models.CharField(max_length=255)

Querying for modification since

It is now possible for you to see which instances of a model have been created or modified since a specific time or version

import time

# create instance
test = Test.objects.create(name="This is a test")

# keep track of time, we need this later
t = time.time()

# modifying and saving it
test.name = "Changed my mind"
test.save()

# now we can use the handleref manager to retrieve it
Test.handleref.since(timestamp=t).count() # 1
Test.handleref.since(timestamp=time.time().count() #0

Soft delete

By default all models extending HandleRefModel will softdelete when their delete() method is called. Note that this currently wont work for batch deletes - as this does not call the delete() method.

test = Test.objects.get(id=1)
test.delete()

# querying handleref undeleted will not contain the deleted object
Test.handleref.undeleted().filter(id=1).count() #0

# querying handleref since will not contain the deleted object
Test.handleref.since(timestamp=t).filter(id=1).count() #0

# passing deleted=True to handleref since will contain the deleted object
Test.handleref.since(timestamp=t, deleted=True).filter(id=1).count() #1

# querying using the standard objects manager will contain the deleted object
Test.objects.filter(id=1).count() #1

# You may also still hard-delete by passing hard=True to delete
test.delete(hard=True)
Test.objects.filter(id=1).count() #0

Versioning (with django-reversion)

Requires

django-reversion==1.8.7

When django-reversion is installed all your HandleRefModels will be valid for versioning.

import reversion

with reversion.create_revision():
    obj = Test.objects.create(name="This is a test")
    obj.save()

    obj.version #1

    obj.name = "Changed my mind"
    obj.save()

    obj.version #2

Test.handleref.since(version=1).count() #1

License

Copyright 2015-2021 20C, LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this softare except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.