litestar-django 0.2.2

Django model support for Litestar

Litestar-Django

Django model support for Litestar, implemented via Litestar DTOs.

from litestar import get, Litestar
from litestar_django import DjangoModelPlugin
from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)


class Genre(models.Model):
    name = models.CharField(max_length=50)


class Book(models.Model):
    name = models.CharField()
    author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name="books")
    genres = models.ManyToManyField(Genre, related_name="books")


@get("/{author_id:int}")
async def handler(author_id: int) -> Author:
    return await Author.objects.prefetch_related("books").aget(id=author_id)


app = Litestar([handler], plugins=[DjangoModelPlugin()])

This minimal setup will provide serialization of Django objects returned from handlers, complete with OpenAPI schema generation.

Installation

pip install litestar-django

Usage

Directly constructing a DTO

from litestar import get
from litestar_django import DjangoModelDTO
from app.models import Author

@get("/{author_id:int}", dto=DjangoModelDTO[Author])
async def handler(author_id: int) -> Author:
    return await Author.objects.prefetch_related("books").aget(id=author_id)

Automatically creating DTOs via the plugin

from litestar import get
from litestar_django import DjangoModelPlugin
from app.models import Author

@get("/{author_id:int}")
async def handler(author_id: int) -> Author:
    return await Author.objects.prefetch_related("books").aget(id=author_id)

app = Litestar([handler], plugins=[DjangoModelPlugin()])

Creating a model instance from a DTO

from typing import Annotated
from litestar import post
from litestar.dto import DTOConfig
from litestar_django import DjangoModelDTO
from app.models import Author

@post(
    "/",
    sync_to_thread=True,
    dto=DjangoModelDTO[
       Annotated[
          Author,
          # exclude primary key and relationship fields
          DTOConfig(exclude={"id", "books"})
       ]
    ],
    return_dto=DjangoModelDTO[Author],
)
async def handler(data: Author) -> Author:
    await data.asave()
    return data

OpenAPI

Full OpenAPI schemas are generated from models based on their field types:

Type map

Field	OpenAPI type	OpenAPI format
models.JSONField	{}
models.DecimalField	number
models.DateTimeField	string	date-time
models.DateField	string	date
models.TimeField	string	duration
models.DurationField	string	duration
models.FileField	string
models.FilePathField	string
models.UUIDField	string	uuid
models.IntegerField	integer
models.FloatField	number
models.BooleanField	boolean
models.CharField	string
models.TextField	string
models.BinaryField	string	byte

Additional properties

The following properties are extracted from fields, in addition to its type:

OpenAPI property	From
title	Field.verbose_name
description	Field.help_text
enum	Field.choices
exclusiveMinimum	MinValueValidator
exclusiveMaximum	MaxValueValidator
minLength	MinLengthValidator
maxLength	MaxLengthValidator

Relationships

Relationships will be represented as individual components, referenced in the schema.

Lazy loading

[!IMPORTANT] Since lazy-loading is not supported in an async context, you must ensure to always load everything consumed by the DTO. Not doing so will result in a SynchronousOnlyOperation exception being raised by Django

This can be mitigated by:

1. Setting include or exclude rules to only include necessary fields (docs)
2. Configuring nested relationships with an appropriate max_nexted_depth (docs)
3. Using select_related and prefetch_related to ensure relationships are fully loaded

Foreign keys

When defining a ForeignKey field, Django will implicitly generate another field on the model with an _id suffix, to store the actual foreign key value. The DTO will include these implicit fields.

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    name = models.CharField(max_length=100)
    author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name="books")

In this example, the DTO for Book includes the field definitions

• id: int
• name: str
• author_id: int
• author: Author

Serialization / validation of 3rd party field types

Additionally, the following 3rd party fields / types are supported if the DjangoModelPlugin is installed:

• django-enumfields
• django-enumfields2

Contributing

All Litestar Organization projects are open for contributions of any size and form.

If you have any questions, reach out to us on Discord or our org-wide GitHub discussions page.

---

An official Litestar Organization Project