Django ChangeSet

Django ChangeSet is a simple Django app that will give your models the possibility to track all changes. It depends on django_userforeignkey to determine the current user doing the change(s).

Currently, Django 2.2 and 3.2 are supported and tested via GitHub Actions.

Detailed documentation is in the docs subdirectory.

Quick start

1. Use pip to install and download django-changeset (and django-userforeignkey):

pip install django-changeset

2. Add django_userforeignkey and django_changeset to your INSTALLED_APPS like this:

INSTALLED_APPS = [
    ...
    'django_userforeignkey',
    'django_changeset',
]

3. Add django_userforeignkey.middleware.UserForeignKeyMiddleware to your MIDDLEWARE like this:

MIDDLEWARE = (
    ...
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    ...
    'django_userforeignkey.middleware.UserForeignKeyMiddleware',
)

Note: Make sure to insert the UserForeignKeyMiddleware after Djangos AuthenticationMiddleware.

Example usage

Use RevisionModelMixin as a mixin class for your models and add the fields you want to track in the meta configuration using track_fields and track_related. Also add a generic relation to ChangeSet using changesets = ChangeSetRelation():

from django.db import models

from django_changeset.models import RevisionModelMixin
from django_changeset.models.fields import ChangeSetRelation


class MyModel(models.Model, RevisionModelMixin):
    class Meta:
        track_fields = ('my_data', )  # track changes on my_data
        track_related = ('my_ref', )  # track changes on a related model

    my_data = models.CharField(max_length=64, verbose_name="Very important data you want to track")
    my_ref = models.ForeignKey('SomeOtherModel', verbose_name="Very important relation", related_name='my_models')

    # Generic Relation to ChangeSet
    changesets = ChangeSetRelation()

Note: If you want to have access to the properties created_by, created_at, last_modified_by, last_modified_at, you need to inherit from CreatedModifiedByMixin aswell as RevisionModelMixin. For the Python MRO to work, you also have to create an abstract base model:

from django.db import models

from django_changeset.models import CreatedModifiedByMixin, RevisionModelMixin
from django_changeset.models.fields import ChangeSetRelation



class BaseModel(models.Model):
    """
    BaseModel is needed for proper MRO within Python/Django Models
    """
    class Meta:
        abstract = True
    pass


class MyModel(BaseModel, RevisionModelMixin, CreatedModifiedByMixin):
    class Meta:
        track_fields = ('my_data', )  # track changes on my_data
        track_related = ('my_ref', )  # track changes on a related model

    my_data = models.CharField(max_length=64, verbose_name="Very important data you want to track")
    my_ref = models.ForeignKey('SomeOtherModel', verbose_name="Very important relation", related_name='my_models')

    # Generic Relation to ChangeSet
    changesets = ChangeSetRelation()

Querying ChangeSets via the changesets relation

By inheriting from the RevisionModelMixin and CreatedModifiedByMixin mixins, and adding an attribute of type ChangeSetRelation (a GenericRelation for the changeset), the following features are added to your model:

• Properties created_by, created_at, last_modified_by, last_modified_at are made available for each object (CreatedModifiedByMixin)
• Relation changesets is made available, allowing you to run queries like this one: MyModel.objects.filter(changesets__changeset_type='I', changesets__user__username='johndoe')

Access ChangeSets and ChangeRecords

ToDo

You can access the changeset by calling the change_set property of an instance of MyModel as shown in the following example:

print("------- CHANGE SETS (", len(somemodel.changesets), ")---------")
for change_set in somemodel.changesets:
    # print change_set
    print("Change was carried out at ", change_set.date, " by user ", change_set.user, " on model ", change_set.object_type)

    print("  + CHANGE RECORDS (", len(change_set.change_records.all()), "): ")
    for change_record in change_set.change_records.all():
        print("\t", change_record)
        print("\tIs change on a related field?", change_record.is_related)
        # related fields: we only know that something new has been added. we know the PK, but not the object itself
        print("\t\tChanged field ", change_record.field_name, "(", change_record.field_verbose_name, ") from ",
              change_record.old_value, "(display:", change_record.old_value_display, ") to")
        print("\t\t ", change_record.new_value, "(display:", change_record.new_value_display, ")")
        if change_record.is_related:
            print("\t\tRelated Object Info: ", change_record.related_object)
    # TODO:
    # change_set.created_at, change_set.created_by, change_set.last_modified_by, change_set.last_modified_at

    print("-----")

Maintainers

This repository is currently maintained by

• beachmachine
• anx-mpoelzl

Pull Requests are welcome.

License

Django ChangeSet uses the BSD-3 Clause License, see LICENSE file.