drf-nest

Writable nested serialisers for Django Rest Framework

The sample

A sample project is included which implements a retail type use case.

• Sales have a foreign key to a store
• Sale items have foreign keys to the sale.

To run sample:

pip install -r requirements.txt
python manage.py migrate
python manage.py createsuperuser super super@super.com super
python manage.py runserver

To use

python setup.py install

In your serialisers.py file import extensions:

from drf_nest.serializers import ExtendedHyperlinkedSerialiser
from drf_nest.serializer_fields import ExtendedModelSerialiserField

For each model serialiser using nested field use the ExtendedHyperlinkedSerialiser

class SaleSerialiser(ExtendedHyperlinkedSerialiser):

For each nested representation in the parent object use the ExtendedModelSerialiserField

class SaleSerialiser(ExtendedHyperlinkedSerialiser):
    sale_items = ExtendedModelSerialiserField(
        SaleItemSerialiser(), 
        many=True, 
        required=False, 
        allow_null=True)

We won't know the foreign key to fulfill the relationship if we are creating the parent so in each sub objects serialiser, the parent object must be made optional.

class SaleItemSerialiser(ExtendedHyperlinkedSerialiser):
    sale = serializers.HyperlinkedRelatedField(
        required=False,
        view_name='sale-detail',
        queryset=Sale.objects.all()
    )

How does it work

The serialiser field overrides the to internal function to return a dictionary (or list of dictionaries) rather than the django model instance. This is done because the fields do not know if the parent exists already but may have a required foreign key constraint.

Features

See the sample project tests for example POST requests.

• During POST, PUT and PATCH user can specify nested object either by URL or full serialised representation
• Adds type field to allow for generic foreign keys (in development)
• Serialisation of model with foreign key
• Serialisation of model with reverse relationship
• Serialisation of model with many to many relationship