Ninja Schema

Ninja Schema converts your Django ORM models to Pydantic schemas with more Pydantic features supported.

Inspired by: django-ninja and djantic

Notice

Starting version 0.13.4, Ninja schema will support both v1 and v2 of pydantic library and will closely monitor V1 support on pydantic package.

Requirements

Python >= 3.8 django >= 3 pydantic >= 1.6

Key features:

• Custom Field Support: Ninja Schema converts django model to native pydantic types which gives you quick field validation out of the box. eg Enums, email, IPAddress, URLs, JSON, etc
• Field Validator: Fields can be validated with model_validator just like pydantic validator or root_validator.

Installation

pip install ninja-schema

Example

Checkout this sample project: https://github.com/eadwinCode/bookstoreapi

Configuration Properties

• model: Django Model
• include: Fields to include, default: '__all__'. Please note that when include = __all__, model's PK becomes optional
• exclude: Fields to exclude, default: set()
• optional: Fields to mark optional, default: set() optional = '__all__' will make all schema fields optional
• depth: defines depth to nested generated schema, default: 0

model_validator(*args, **kwargs)

model_validator is a substitute for pydantic validator used for pre and post fields validation. There functionalities are the same. More info pydantic validators

from django.contrib.auth import get_user_model
from ninja_schema import ModelSchema, model_validator

UserModel = get_user_model()


class CreateUserSchema(ModelSchema):
    class Config:
        model = UserModel
        include = ['username', 'email', 'password']

    @model_validator('username')
    def validate_unique_username(cls, value_data: str) -> str:
        if UserModel.objects.filter(username__icontains=value_data).exists():
            raise ValueError('Username exists')
        return value_data

from_orm(cls, obj: Any)

You can generate a schema instance from your django model instance

from django.contrib.auth import get_user_model
from ninja_schema import ModelSchema, model_validator

UserModel = get_user_model()
new_user = UserModel.objects.create_user(
    username='eadwin', email='eadwin@example.com', 
    password='password', first_name='Emeka', last_name='Okoro'
)


class UserSchema(ModelSchema):
    class Config:
        model = UserModel
        include = ['id','first_name', 'last_name', 'username', 'email']

schema = UserSchema.from_orm(new_user)
print(schema.json(indent=2)
{
    "id": 1,
    "first_name": "Emeka",
    "last_name": "Okoro",
    "email": "eadwin@example.com",
    "username": "eadwin",
}

apply_to_model(self, model_instance, **kwargs)

You can transfer data from your ModelSchema to Django Model instance using the apply function. The apply_to_model function uses Pydantic model .dict function, dict function filtering that can be passed as kwargs to the .apply function.

For more info, visit Pydantic model export

from django.contrib.auth import get_user_model
from ninja_schema import ModelSchema

UserModel = get_user_model()
new_user = UserModel.objects.create_user(username='eadwin', email='eadwin@example.com', password='password')


class UpdateUserSchema(ModelSchema):
    class Config:
        model = UserModel
        include = ['first_name', 'last_name', 'username']
        optional = ['username']  # `username` is now optional

schema = UpdateUserSchema(first_name='Emeka', last_name='Okoro')
schema.apply_to_model(new_user, exclude_none=True)

assert new_user.first_name == 'Emeka' # True
assert new_user.username == 'eadwin' # True

Generated Schema Sample

from django.contrib.auth import get_user_model
from ninja_schema import ModelSchema, model_validator

UserModel = get_user_model()


class UserSchema(ModelSchema):
    class Config:
        model = UserModel
        include = '__all__'
        depth = 2

        
print(UserSchema.schema())

{
    "title": "UserSchema",
    "type": "object",
    "properties": {
        "id": {"title": "Id", "extra": {}, "type": "integer"},
        "password": {"title": "Password", "maxLength": 128, "type": "string"},
        "last_login": {"title": "Last Login","type": "string", "format": "date-time"},
        "is_superuser": {"title": "Superuser Status",
            "description": "Designates that this user has all permissions without explicitly assigning them.",
            "default": false,
            "type": "boolean"
        },
        "username": {
            "title": "Username",
            "description": "Required. 150 characters or fewer. Letters, digits and @/./+/-/_ only.",
            "maxLength": 150,
            "type": "string"
        },
        "first_name": {
            "title": "First Name",
            "maxLength": 150,
            "type": "string"
        },
        "last_name": {
            "title": "Last Name",
            "maxLength": 150,
            "type": "string"
        },
        "email": {
            "title": "Email Address",
            "type": "string",
            "format": "email"
        },
        "is_staff": {
            "title": "Staff Status",
            "description": "Designates whether the user can log into this admin site.",
            "default": false,
            "type": "boolean"
        },
        "is_active": {
            "title": "Active",
            "description": "Designates whether this user should be treated as active. Unselect this instead of deleting accounts.",
            "default": true,
            "type": "boolean"
        },
        "date_joined": {
            "title": "Date Joined",
            "type": "string",
            "format": "date-time"
        },
        "groups": {
            "title": "Groups",
            "description": "The groups this user belongs to. A user will get all permissions granted to each of their groups.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Group"
            }
        },
        "user_permissions": {
            "title": "User Permissions",
            "description": "Specific permissions for this user.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Permission"
            }
        }
    },
    "required": [
        "password",
        "username",
        "groups",
        "user_permissions"
    ],
    "definitions": {
        "Permission": {
            "title": "Permission",
            "type": "object",
            "properties": {
                "id": {
                    "title": "Id",
                    "extra": {},
                    "type": "integer"
                },
                "name": {
                    "title": "Name",
                    "maxLength": 255,
                    "type": "string"
                },
                "content_type_id": {
                    "title": "Content Type",
                    "type": "integer"
                },
                "codename": {
                    "title": "Codename",
                    "maxLength": 100,
                    "type": "string"
                }
            },
            "required": [
                "name",
                "content_type_id",
                "codename"
            ]
        },
        "Group": {
            "title": "Group",
            "type": "object",
            "properties": {
                "id": {
                    "title": "Id",
                    "extra": {},
                    "type": "integer"
                },
                "name": {
                    "title": "Name",
                    "maxLength": 150,
                    "type": "string"
                },
                "permissions": {
                    "title": "Permissions",
                    "type": "array",
                    "items": {
                        "$ref": "#/definitions/Permission"
                    }
                }
            },
            "required": [
                "name",
                "permissions"
            ]
        }
    }
}