Django Staskstore model

django-staskstore-model is a library that can support model versioning in a minimal amount of steps.

• Support Django 2 and 3
• Support Python3.7, 3.8 (Maybe 2.7. Not tested)
• Admin extensions are supported.

Usage

Model

# models.py
from stackstore.models import AbstractStackModel


class MySampleModel(AbstractStackModel):
    title = models.CharField(
        max_length=100,
        null=False,
        blank=False,
    )

    body = models.TextField(
        max_length=1000,
        null=False,
        blank=False,
    )

Python shell

# Create First version instance
>>> instance = MySampleModel.objects.create(title="Test", body="This is test text")
>>> instance.pk
1

# If you save this instance, create new version instance
>>> instance.title = "Test (version2)"
>>> instance.save()
>>> instance.pk
2

# If you can fetch previous version
>>> previous_instance = instance.previous_instance()
>>> previous_instance.pk
1

# You can get next version
>>> previous_instance.next_instance().pk
2

Admin Extension

Filter to show only the latest version of the object

Show only items with the same stackgroup_uuid

API

QuerySet & Manager

latest_from_stack_group

Returns a QuerySet of the most recent objects in each Stackgroup.

# Create instance
>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> instance_lunch = MySampleModel.objects.create(title="Today's lunch", body="Spam with Beacon") # Create <MySampleModel: MySampleModel object (2)>

# Save each instance
>>> instance_breakfast.body = "Fried Egg with bread"
>>> instance_breakfast.save() # Save method create new <MySampleModel: MySampleModel object (3)>

>>> instance_lunch.body = "Meat Pasta"
>>> instance_lunch.save() # Save method create new <MySampleModel: MySampleModel object (4)>

>>> MySampleModel.objects.latest_from_stack_group() # You can fetch 3 & 4 My Sample Model
<StackStoreQuerySet [<MySampleModel: MySampleModel object (3)>, <MySampleModel: MySampleModel object (4)>]>

get_latest_from_stack_group

Returns an object that matches the collation parameter from the latest set of objects in each Stackgroup.

# Create instance
>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> instance_lunch = MySampleModel.objects.create(title="Today's lunch", body="Spam with Beacon") # Create <MySampleModel: MySampleModel object (2)>

# Save each instance
>>> instance_breakfast.body = "Fried Egg with bread"
>>> instance_breakfast.save() # Save method create new <MySampleModel: MySampleModel object (3)>

>>> MySampleModel.objects.get_latest_from_stack_group(body="Fried Egg with bread")
<MySampleModel: MySampleModel object (3)>

model object

save

When an object is saved, a new object is created and assigned the same stack_group_uuid as the object from which it was saved. This means that a new version will be generated.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> instance_breakfast.body = "Fried Egg with bread"
>>> instance_breakfast.save() # Save method create version object <MySampleModel: MySampleModel object (2)>
>>> MySampleModel.objects.all()
<StackStoreQuerySet [<MySampleModel: MySampleModel object (1)>, <MySampleModel: MySampleModel object (2)>]>

If you want to save the overwrite without creating a new version, you should pass False to __create_new_version in the save method.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg")
>>> instance_breakfast.save(__create_new_version=False)
>>> instance_breakfast.pk
1

force_delete

Remove the object.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> MySampleModel.objects.all()
<StackStoreQuerySet [<MySampleModel: MySampleModel object (1)>]>
>>> instance_breakfast.force_delete()
>>> MySampleModel.objects.all()
<StackStoreQuerySet []>

Calling the existing delete method will raise a NotImplementedError exception.

same_group_items

Returns a QuerySet that returns all objects belonging to the same Stackgroup.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> [instance_breakfast.save() for i in range(2)]
>>> instance_breakfast.same_group_items()
<StackStoreQuerySet [<MySampleModel: MySampleModel object (3)>, <MySampleModel: MySampleModel object (2)>, <MySampleModel: MySampleModel object (1)>]>

previous_instance

Returns the previous version of the object.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> [instance_breakfast.save() for i in range(2)]
>>> second_gen_instance = instance_breakfast.same_group_items().order_by("pk")[1]
>>> second_gen_instance.previous_instance()
<MySampleModel: MySampleModel object (1)>

Throws a DoesNotExist exception if the object does not exist.

next_instance

Returns the next version of the object.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> [instance_breakfast.save() for i in range(2)]
>>> second_gen_instance = instance_breakfast.same_group_items()[1]
>>> second_gen_instance.next_instance()
<MySampleModel: MySampleModel object (3)>

Throws a DoesNotExist exception if the object does not exist.

latest_instance

Returns the most recent object of the Stackgroup to which its own object belongs.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> [instance_breakfast.save() for i in range(2)]
>>> first_gen_instance = instance_breakfast.same_group_items().order_by("pk")[0]
>>> first_gen_instance.latest_instance()
<MySampleModel: MySampleModel object (3)>

Throws a DoesNotExist exception if the object does not exist.

earliest_instance

Returns the oldest object in the Stackgroup to which its own object belongs.

>>> instance_breakfast = MySampleModel.objects.create(title="Today's breakfast", body="Spam with Egg") # Create <MySampleModel: MySampleModel object (1)>
>>> [instance_breakfast.save() for i in range(2)]
>>> third_gen_instance = instance_breakfast.same_group_items().order_by("pk")[2]
>>> third_gen_instance.earliest_instance()
<MySampleModel: MySampleModel object (1)>

Throws a DoesNotExist exception if the object does not exist.

Demo

The Docker configuration is provided. Please use the following command to start it. Go to http://localhost:8000 when the launch is complete.

$ docker-compose up

Login account is ID: admin Password: admin

License

MIT License