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Request Body

Request bodies are typically used with “create” and “update” operations (POST, PUT, PATCH). For example, when creating a resource using POST or PUT, the request body usually contains the representation of the resource to be created.

To declare a request body, you need to use Django Ninja Schema.

Info

Under the hood Django Ninja uses Pydantic models with all their power and benefits. The alias Schema was picked to avoid confusion in code with Django models.

Import Schema

First, you need to import Schema from ninja:

from ninja import Schema


class Item(Schema):
    name: str
    description: str = None
    price: float
    quantity: int


@api.post("/items")
def create(request, item: Item):
    return item

Create your data model

Then you declare your data model as a class that inherits from Schema.

Use standard Python types for all the attributes:

from ninja import Schema


class Item(Schema):
    name: str
    description: str = None
    price: float
    quantity: int


@api.post("/items")
def create(request, item: Item):
    return item

Note: if you use None as default value for an attribute - it will become optional in the request body. For example, this model above declares a JSON "object" (or Python dict) like:

{
    "name": "Katana",
    "description": "An optional description",
    "price": 299.00,
    "quantity": 10
}

...as description is optional (with a default value of None), this JSON "object" would also be valid:

{
    "name": "Katana",
    "price": 299.00,
    "quantity": 10
}

Declare it as a parameter

To add it to your path operation, declare it the same way you declared path and query parameters:

from ninja import Schema


class Item(Schema):
    name: str
    description: str = None
    price: float
    quantity: int


@api.post("/items")
def create(request, item: Item):
    return item

...and declare its type as the model you created, Item.

Results

With just that Python type declaration, Django Ninja will:

  • Read the body of the request as JSON.
  • Convert the corresponding types (if needed).
  • Validate the data.
    • If the data is invalid, it will return a nice and clear error, indicating exactly where and what was the incorrect data.
  • Give you the received data in the parameter item.
    • As you declared it in the function to be of type Item, you will also have all the editor support (completion, etc) for all of the attributes and their types.
  • Generate JSON Schema definitions for your model, you can also use them anywhere else you like if it makes sense for your project.
  • Those schemas will be part of the generated OpenAPI schema, and used by the automatic documentation UIs.

Automatic docs

The JSON Schemas of your models will be part of your OpenAPI generated schema, and will be shown in the interactive API docs:

Openapi schema

And will be also used in the API docs inside each path operation that needs them:

Openapi schema

Editor support

In your editor, inside your function you will get type hints and completion everywhere (this wouldn't happen if you received a dict instead of a Schema object):

Type hints

The previous screenshots were taken with Visual Studio Code.

But you would get the same editor support with PyCharm and most of the other Python editors.

Request body + path parameters

You can declare path parameters and body requests at the same time.

Django Ninja will recognize that the function parameters that match path parameters should be taken from the path, and that function parameters that are declared with Schema should be taken from the request body.

from ninja import Schema


class Item(Schema):
    name: str
    description: str = None
    price: float
    quantity: int


@api.put("/items/{item_id}")
def update(request, item_id: int, item: Item):
    return {"item_id": item_id, "item": item.dict()}

Request body + path + query parameters

You can also declare body, path and query parameters, all at the same time.

Django Ninja will recognize each of them and take the data from the correct place.

from ninja import Schema


class Item(Schema):
    name: str
    description: str = None
    price: float
    quantity: int


@api.post("/items/{item_id}")
def update(request, item_id: int, item: Item, q: str):
    return {"item_id": item_id, "item": item.dict(), "q": q}

The function parameters will be recognized as follows:

  • If the parameter is also declared in the path, it will be used as a path parameter.
  • If the parameter is of a singular type (like int, float, str, bool, etc) it will be interpreted as a query parameter.
  • If the parameter is declared to be of the type of a Schema (or Pydantic BaseModel), it will be interpreted as a request body.