django-neomodel

To ensure a clean state during testing, use clear_neo4j_database from neomodel in your test class's setUp method.

from neomodel import db, clear_neo4j_database
from django.test import TestCase

class YourTestClass(TestCase):
    def setUp(self):
        clear_neo4j_database(db)

    def test_something(self):
        pass

To use Neo4j with Django, install the django_neomodel package and add it to your INSTALLED_APPS.

Important: django_neomodel must appear before your own application apps in the INSTALLED_APPS list. If you use django.contrib.auth, ensure django_neomodel is placed before it or your custom apps.

Requirements:

• Python 3.8+
• Neo4j 5.x or 4.4 (LTS)

$ pip install django_neomodel

# settings.py
import os

NEOMODEL_NEO4J_BOLT_URL = os.environ.get('NEO4J_BOLT_URL', 'bolt://neo4j:foobarbaz@localhost:7687')

INSTALLED_APPS = (
    'django_neomodel',
    'yourapp'
)

The following settings are available in your Django configuration. These are mapped to neomodel.config during startup:

• NEOMODEL_NEO4J_BOLT_URL: The connection URL for Neo4j (default: 'bolt://neo4j:neo4j@localhost:7687').
• NEOMODEL_SIGNALS: Enables or disables Django signals (default: True).
• NEOMODEL_FORCE_TIMEZONE: Boolean to force timezone settings (default: False).
• NEOMODEL_MAX_CONNECTION_POOL_SIZE: Maximum size of the connection pool (default: 50).

By default, DjangoNode triggers standard Django model signals during its lifecycle. These signals are sent if NEOMODEL_SIGNALS is set to True in your Django settings (which is the default).

Supported signals:

• pre_save
• post_save (includes a created boolean argument)
• pre_delete
• post_delete

Once a model inherits from DjangoNode, it can be used with standard Django ModelForm classes just like a regular Django ORM model.

from django import forms
from .models import Book

class BookForm(forms.ModelForm):
    class Meta:
        model = Book
        fields = ['title', 'status']

Signals work with DjangoNode subclasses. You can connect to standard Django signals like pre_save, post_save, pre_delete, and post_delete.

In the post_save signal, the created argument will be True if the node was freshly created.

from django.db.models import signals
from django_neomodel import DjangoNode
from neomodel import StringProperty

class Book(DjangoNode):
    title = StringProperty(unique_index=True)
    class Meta:
        app_label = 'library'

def your_signal_func(sender, instance, signal, created):
    pass

signals.post_save.connect(your_signal_func, sender=Book)

While you can use standard neomodel.StructuredNode, you should use django_neomodel.DjangoNode if you want to use Django features like Model Forms and Signals.

When using DjangoNode, you must include a Meta class with an app_label to integrate with Django's app registry.

from datetime import datetime
from django_neomodel import DjangoNode
from neomodel import StringProperty, DateTimeProperty, UniqueIdProperty

class Book(DjangoNode):
    uid = UniqueIdProperty()
    title = StringProperty(unique_index=True)
    status = StringProperty(choices=(('Available', 'A'), ('On loan', 'L'), ('Damaged', 'D')), default='Available')
    created = DateTimeProperty(default=datetime.utcnow)

    class Meta:
        app_label = 'library'

Django Neomodel allows you to configure the underlying neomodel settings directly through your Django settings.py file. The following Django settings are supported and will override the default neomodel configuration:

• NEOMODEL_NEO4J_BOLT_URL: Sets the Neo4j Bolt URL (maps to neomodel.config.DATABASE_URL).
• NEOMODEL_FORCE_TIMEZONE: A boolean that determines if timezones should be forced (maps to neomodel.config.FORCE_TIMEZONE).
• NEOMODEL_MAX_CONNECTION_POOL_SIZE: Sets the maximum size of the connection pool (maps to neomodel.config.MAX_CONNECTION_POOL_SIZE).

The clear_neo4j management command deletes all nodes in your database.

Warning: This command does not prompt for confirmation and is destructive.

$ python manage.py clear_neo4j

After defining or changing your node models (constraints, indexes, or properties), you must run the install_labels management command to apply these changes to the Neo4j database.

$ python manage.py install_labels

To make your Neomodel classes visible and editable in the Django admin interface, use the register function provided by django_neomodel.admin. This function acts as a wrapper around the standard django.contrib.admin.site.register method, specifically designed to handle Neomodel classes.

Usage:

1. Define your ModelAdmin class (inheriting from admin.ModelAdmin).
2. Call register(YourNeomodelClass, YourModelAdminClass).

from django_neomodel.admin import register
from .models import MyNeomodel
from django.contrib import admin

class MyModelAdmin(admin.ModelAdmin):
    pass

register(MyNeomodel, MyModelAdmin)

The classproperty decorator allows you to define a property that is accessed at the class level, similar to how @property works for instances. In django-neomodel, this is used to implement the _meta attribute on DjangoNode classes.

from django_neomodel import classproperty

class MyModel:
    @classproperty
    def my_class_attr(self):
        return "value"

# Accessed via the class, not an instance
print(MyModel.my_class_attr)