django-materialized-paths

Django Materialized Paths

A simple and lightweight implementation of materialized path tree structures in Django.

Installation

To install, run:

pip install django-materialized-paths

Configuration

Add the following into the INSTALLED_APPS of your projects:

INSTALLED_APPS = (
 ...
 'django-materialized-paths',
)

Usage

To use, extend the BaseNode into your model:

from django-materialized-paths import BaseNode

class FolderExample(BaseNode):
    """My folder class"""
    name = models.CharField(max_length=48)

The model overrides Django's django.db.models.Model save() method to automatically manage changes to inheritance:

from .models import FolderExample # concrete class from above

root = FolderExample.objects.create(name="root")
child = FolderExample.objects.create(name="child", parent=root)
grandchild = FolderExample.objects.create(name="child", parent=child)

For example, to convert grandchild to a root:

grandchild.parent = None
grandchild.save()

Usage - Properties and Inherited

BaseNode.depth # Root is 0
BaseNode.parent
BaseNode.children # Only returns direct descendants

BaseNode.save() # Set the parent field to automatically manage hierarchy
BaseNode.delete() # NOTE: The BaseNode.parent field is set to cascade, so deleting a parent will delete all children 

Usage - Methods

Note that these methods generally return querysets

# Accessors

BaseNode.get_root()
BaseNode.get_ancestor(depth=int)
BaseNode.get_ancestors() 
BaseNode.get_descendants() 
BaseNode.get_siblings() 

# Convenience

BaseNode.has_children()
BaseNode.is_child_of(parent_id=int)

# ID-based accessors - computed directly from path without accessing db

BaseNode.get_ancestors_ids()
BaseNode.get_descendants_ids()

Authors

• Cameron McNierney - Original author - https://github.com/cmcnierney

License

This project is licensed under the MIT License - see the LICENSE.md file for details