Use pydantic with Django REST framework

• Introduction
• Installation
• Usage
  • General
  • Existing Models
  • Nested Models
• Roadmap

Introduction

Pydantic is a Python library used to perform data serialization and validation.

Django REST framework is a framework built on top of Django used to write REST APIs.

If you develop DRF APIs and rely on pydantic for data validation/(de)serialization , then drf-pydantic is for you 😍.

ℹ️ INFO
drf_pydantic supports pydantic v2. Due to breaking API changes in pydantic v2 support for pydantic v1 is available only in drf_pydantic 1.*.*.

Installation

pip install drf-pydantic

Usage

General

Use drf_pydantic.BaseModel instead of pydantic.BaseModel when creating your models:

from drf_pydantic import BaseModel

class MyModel(BaseModel):
  name: str
  addresses: list[str]

MyModel.drf_serializer would be equvalent to the following DRF Serializer class:

class MyModelSerializer:
    name = CharField(allow_null=False, required=True)
    addresses = ListField(
      allow_empty=True,
      allow_null=False,
      child=CharField(allow_null=False),
      required=True,
    )

Whenever you need a DRF serializer you can get it from the model like this:

my_value = MyModel.drf_serializer(data={"name": "Van", addresses: ["Gym"]})
my_value.is_valid(raise_exception=True)

ℹ️ INFO
Models created using drf_pydantic are fully idenditcal to those created by pydantic. The only change is the addition of the drf_serializer attribute.

Existing Models

If you have an existing code base and you would like to add the drf_serializer attribute only to some of your models, then I have great news 🥳 - you can easily extend your existing pydantic models by adding drf_pydantic.BaseModel to the list of parent classes of the model you want to extend.

Your existing pydantic models:

from pydantic import BaseModel

class Pet(BaseModel):
  name: str

class Dog(Pet):
  breed: str

Update your Dog model and get serializer via the drf_serializer:

from drf_pydantic import BaseModel as DRFBaseModel
from pydantic import BaseModel

class Pet(BaseModel):
  name: str

class Dog(DRFBaseModel, Pet):
  breed: str

Dog.drf_serializer

⚠️ ATTENTION
Inheritance order is important: drf_pydantic.BaseModel must always go before the pydantic.BaseModel class.

Nested Models

If you have nested models and you want to generate serializer only from one of them, you don't have to update all models - only update the model you need, drf_pydantic will generate serializers for all normal nested pydantic models for free 🥷.

from drf_pydantic import BaseModel as DRFBaseModel
from pydantic import BaseModel

class Apartment(BaseModel):
  floor: int
  tenant: str

class Building(BaseModel):
  address: str
  aparments: list[Apartment]

class Block(DRFBaseModel):
  buildings: list[Buildind]

Block.drf_serializer

Roadmap

• Add support for custom field types (both for pydantic and DRF)
• Add option to create custom serializer for complex models