django-neomodel 0.0.1

An object mapper for the neo4j graph database.

Django Neomodel (beta!)

This module allows you to use the neo4j graph database with Django using neomodel

Getting started

Install the module:

$ pip install django_neomodel

Add the following settings to your settings.py:

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

# Make sure django_neomodel comes before your own apps
INSTALLED_APPS = (
    # django.contrib.auth etc
    'django_neomodel',
    'yourapp'
)

Write your first node definition in yourapp/models.py:

from neomodel import StructuredNode, StringProperty, DateProperty

class Book(StructuredNode):
    title = StringProperty(unique_index=True)
    published = DateProperty()

Create any constraints or indexes for your labels. This needs to be done after you change your node definitions much like manage.py migrate:

$ python manage.py install_labels

Now in a view yourapp/views.py:

from .models import Book

def get_books(request):
    return render('yourapp/books.html', request, {'books': Book.nodes.all()})

And you’re ready to go. Don’t forget to check the neomodel documentation.

Model forms

Switch the base class from StructuredNode to DjangoNode and add a ‘Meta’ class:

from datetime import datetime
from django_neomodel import DjangoNode
from neomodel import StructuredNode, 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'

Create a model form class for your DjangoNode:

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

This class may now be used just like any other Django form.

Settings

The following settings are available with default value shown:

NEOMODEL_NEO4J_BOLT_URL = 'bolt://neo4j:neo4j@localhost:7687'
NEOMODEL_SIGNALS = True
NEOMODEL_FORCE_TIMEZONE = False

Signals

Signals work as expected with StructuredNode sub-classes:

from django.db.models import signals
from neomodel import StructuredNode, StringProperty

class Book(StructuredNode):
  title = StringProperty(unique_index=True)

signals.post_save.connect(your_func, sender=Library)

Testing

You can create a setup method which clears the database before executing each test:

from neomodel import db, clear_neo4j_database

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

    def test_something(self):
        pass

Management Commands

The following django management commands have been included.

install_labels

Setup constraints and indexes on labels to match your node definitions. This should be executed after any schema changes:

$ python manage.py install_labels
Setting up labels and constraints...

+ Creating unique constraint for title on label Book for class tests.someapp.models.Book
tests.someapp.models.Book done.
Finished.

clear_neo4j

Delete all nodes in your database, warning there is no confirmation!

Requirements

• Python 2.7, 3.4+

• neo4j 3.0+