Django MongoEngine

This package, unlike Django-MongoEngine or Djongo, doesn't aim on changing SQL role in Django. Writing backend for NoSQL database is not trivial. Here MongoDB is used as helper database, to increase performance.

Installation

To install the package by pip run following command

# From Github
$ pip install git+https://github.com/giorgi94/djmongoengine.git

Usage

To start using the package, add djmongoengine to INSTALLED_APPS and define MONGODB_DATABASES

# settings.py

INSTALLED_APPS = [
    ...
    djmongoengine
    ...
]

MONGODB_DATABASES = {
    "default": {
        "name": "dbname",
        "host": '127.0.0.1',
        "port": 27017,
        "tz_aware": True,
        # "username": "user",
        # "password": "pass"
    },
}

Package provides mixin for document schema and connector

# models.py

class DocumentMixin:
    @classmethod
    def UpdateOne(cls, instance):
        # updates document in MongoDB, which corresponeds to django instance

    @classmethod
    def from_instance(cls, instance):
        # create mongoengine document based on django instance

We assume that django instance.id is stored in ID, since id returns _id from mongodb. In the example, we provide basic example to define mongoengine schema, based on django models

# myapp/models.py

class Category(models.Model):
    title = models.CharField(max_length=50, unique=True)
    alias = models.CharField(max_length=50)

# myapp/mongo.py

class Category(EmbeddedDocument):

    ID = fields.IntField()

    title = fields.StringField()
    alias = fields.StringField()

    @classmethod
    def from_instance(cls, instance):

        return cls(ID=instance.id, title=instance.title, alias=instance.alias)

In signals.py and receivers.py are defined functions and signals to sync changes in django to mongodb.

GraphQL

GraphQL is not directly connected with the package, but documentation for graphene is not beginner friendly. There are graphene-django and flask-graphql, but it doesn't allow to explore full potential of graphql and mongodb, so we use graphene-mongo for more diversity. Query is defined in

# myapp/query.py


class Query(graphene.ObjectType):
    articles = graphene.List(ArticleQuery, find=FindInput())

    def resolve_articles(self, info, **kwargs):
        find = kwargs.get("find")

        normilize_find(find)

        if find is not None:
            return Article.objects(**find)
        return Article.objects()


schema = graphene.Schema(query=Query)

# myapp/views.py

from .query import schema


def graphql_view(request):
    ...

    result = schema.execute(query)

    if result.errors:
        return JsonResponse({"errors": str(result.errors)})

    return JsonResponse({"query": result.data})