django-pydantic-client 0.1.1

Instantiate Pydantic models directly from Django HttpRequest for request validation

Skip the serializer. Validate Django requests with Pydantic models — one line, zero boilerplate.

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Documentation: https://django-pydantic.readthedocs.io

Source Code: https://github.com/NEFORCEO/django-pydantic

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django-pydantic-client lets you replace manual request parsing in Django views with Pydantic models. Pass a HttpRequest directly to your schema — get a fully validated, typed Python object back, or an automatic HTTP 422 response if validation fails.

Key features:

• One-line validation — data = MySchema(request)
• Automatic 422 errors — middleware converts ValidationError to structured JSON, no try/except needed
• Smart data merging — GET params + POST form / JSON body + URL kwargs, all in one object
• Zero configuration — middleware auto-installs via INSTALLED_APPS, nothing else to do
• Full Pydantic v2 — validators, Field(), model_config, computed fields, custom types

Requirements

• Python 3.10+
• Django 4.2+
• Pydantic 2.0+

Installation

pip install django-pydantic-client

Add to INSTALLED_APPS — that's the only configuration step:

# settings.py
INSTALLED_APPS = [
    ...
    "django_pydantic",
]

PydanticValidationMiddleware is injected automatically. You do not need to touch MIDDLEWARE.

Quick start

Define a schema:

# myapp/schema.py
from pydantic import EmailStr, Field
from django_pydantic import RequestModel


class SignupSchema(RequestModel):
    username: str = Field(min_length=3, max_length=32)
    email: EmailStr
    age: int = Field(ge=18)

Use it in a view:

# myapp/views.py
from django.http import JsonResponse
from .schema import SignupSchema


def signup(request):
    data = SignupSchema(request)          # validates GET / POST / JSON body
    # data.username, data.email, data.age — typed and validated
    return JsonResponse({"username": data.username})

Wire up the URL:

# urls.py
from django.urls import path
from myapp.views import signup

urlpatterns = [
    path("signup/", signup),
]

On invalid input the response is automatic — no extra code required:

{
  "detail": [
    {"type": "missing",     "loc": ["username"], "msg": "Field required"},
    {"type": "value_error", "loc": ["email"],    "msg": "value is not a valid email address"}
  ]
}

How data sources are merged

Source	When used
request.GET	Always (any HTTP method)
request.POST	Non-GET/HEAD/DELETE, no JSON content-type
JSON body	Content-Type: application/json
URL kwargs	Passed explicitly: MySchema(request, pk=pk)

Later sources override earlier ones. URL kwargs always win.

URL path parameters

# urls.py
path("users/<int:pk>/", user_detail)

# views.py
def user_detail(request, pk):
    data = UserSchema(request, pk=pk)    # pk merged with highest priority
    user = User.objects.get(pk=data.pk)
    ...

Full Pydantic v2 support

from pydantic import Field, field_validator, computed_field
from django_pydantic import RequestModel


class OrderSchema(RequestModel):
    product_id: int = Field(gt=0)
    quantity: int   = Field(ge=1, le=100)
    coupon: str     = ""

    @field_validator("coupon")
    @classmethod
    def normalise_coupon(cls, v: str) -> str:
        return v.strip().upper()

    @computed_field
    @property
    def total_label(self) -> str:
        return f"{self.quantity}x product #{self.product_id}"

Class-based views

from django.views import View
from django.http import JsonResponse
from .schema import ArticleCreateSchema


class ArticleView(View):

    def post(self, request):
        data = ArticleCreateSchema(request)
        article = Article.objects.create(
            title=data.title,
            body=data.body,
            author=request.user,
        )
        return JsonResponse({"id": article.pk}, status=201)

Error handling (opt-in)

The middleware handles errors automatically. To customise for a specific view:

from pydantic import ValidationError


def signup(request):
    try:
        data = SignupSchema(request)
    except ValidationError as exc:
        errors = {e["loc"][0]: e["msg"] for e in exc.errors(include_url=False)}
        return JsonResponse({"errors": errors}, status=400)

    return JsonResponse({"ok": True})

License

This project is licensed under the terms of the MIT license.