RelatedObjectsCollector

Overview

RelatedObjectsCollector is a utility class designed to dynamically collect and paginate related objects of a Django model instance before deletion. It ensures that only objects affected by the on_delete action (CASCADE or SET_NULL) are included. The class helps in notifying users about related objects that will be deleted or modified when the instance is removed.

Features

• Automatically collects related objects for a given Django model instance.
• Filters only the related objects that will be deleted or set to NULL.
• Wraps collected objects in a PaginatorObject to maintain a structured output.
• Uses Django's Paginator for easy pagination of results.
• Provides a clean and structured way to analyze the impact of deletion.

Installation

Ensure you have Django installed:

pip install django

Usage

Import and Initialize

from mymodule import RelatedObjectsCollector
from myapp.models import MyModel

instance = MyModel.objects.get(id=1)
collector = RelatedObjectsCollector(instance)

Access Collected Data

print(collector.data)  # Dictionary of related objects

Paginate Related Objects

page_number = 1
page = collector.paginator.get_page(page_number)

for obj in page.object_list:
    print(obj.data)  # Each item contains a related model and its affected objects

Classes

PaginatorObject

A simple wrapper class to store related objects in a way that supports Django’s pagination.

Attributes:

• data: A dictionary containing {model: related_objects}

RelatedObjectsCollector

Responsible for collecting and paginating related objects of a Django model instance.

Attributes:

• data: A dictionary containing {related_model: {on_delete_action: related_objects_queryset}}
• paginator: A Django Paginator instance for paginating the related objects.

Methods:

• __collect_objects(): Gathers related objects dynamically.
• __paginator(values): Initializes a Paginator for collected objects.
• get_on_delete_action(relation): Determines the on_delete behavior (CASCADE, SET_NULL).

Example Output

{
    <class 'myapp.models.Book'>: {
        "delete": [<Book: Django Mastery>, <Book: Advanced Django>]
    },
    <class 'myapp.models.Article'>: {
        "set_null": [<Article: Python Security>, <Article: Django Tips>]
    }
}

License

This project is open-source and available under the MIT License.