django-rest-polymorphic 0.1.5

Polymorphic serializers for Django REST Framework.

Django REST Polymorphic

Polymorphic serializers for Django REST Framework.

Overview

django-rest-polymorphic allows you to easily define serializers for your inherited models that you have created using django-polymorphic library.

Installation

Install using pip:

$ pip install django-rest-polymorphic

Usage

Define your polymorphic models:

# models.py
from django.db import models
from polymorphic.models import PolymorphicModel


class Project(PolymorphicModel):
    topic = models.CharField(max_length=30)


class ArtProject(Project):
    artist = models.CharField(max_length=30)


class ResearchProject(Project):
    supervisor = models.CharField(max_length=30)

Define serializers for each polymorphic model the way you did it when you used django-rest-framework:

# serializers.py
from rest_framework import serializers
from .models import Project, ArtProject, ResearchProject


class ProjectSerializer(serializers.ModelSerializer):
    class Meta:
        model = Project
        fields = ('topic', )


class ArtProjectSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = ArtProject
        fields = ('topic', 'artist', 'url')
        extra_kwargs = {
            'url': {'view_name': 'project-detail', 'lookup_field': 'pk'},
        }


class ResearchProjectSerializer(serializers.ModelSerializer):
    class Meta:
        model = ResearchProject
        fields = ('topic', 'supervisor')

Note that if you extend HyperlinkedModelSerializer instead of ModelSerializer you need to define extra_kwargs to direct the URL to the appropriate view for your polymorphic serializer.

Then you have to create a polymorphic serializer that serves as a mapper between models and serializers which you have defined above:

# serializers.py
from rest_polymorphic.serializers import PolymorphicSerializer


class ProjectPolymorphicSerializer(PolymorphicSerializer):
    model_serializer_mapping = {
        Project: ProjectSerializer,
        ArtProject: ArtProjectSerializer,
        ResearchProject: ResearchProjectSerializer
    }

Create viewset with serializer_class equals to your polymorphic serializer:

# views.py
from rest_framework import viewsets
from .models import Project
from .serializers import ProjectPolymorphicSerializer


class ProjectViewSet(viewsets.ModelViewSet):
    queryset = Project.objects.all()
    serializer_class = ProjectPolymorphicSerializer

Test it:

$ http GET "http://localhost:8000/projects/"

HTTP/1.0 200 OK
Content-Length: 227
Content-Type: application/json

[
    {
        "resourcetype": "Project",
        "topic": "John's gathering"
    },
    {
        "artist": "T. Turner",
        "resourcetype": "ArtProject",
        "topic": "Sculpting with Tim",
        "url": "http://localhost:8000/projects/2/"
    },
    {
        "resourcetype": "ResearchProject",
        "supervisor": "Dr. Winter",
        "topic": "Swallow Aerodynamics"
    }
]

$ http POST "http://localhost:8000/projects/" resourcetype="ArtProject" topic="Guernica" artist="Picasso"

HTTP/1.0 201 Created
Content-Length: 67
Content-Type: application/json

{
    "artist": "Picasso",
    "resourcetype": "ArtProject",
    "topic": "Guernica",
    "url": "http://localhost:8000/projects/4/"
}