Skip to main content

JSON schema generation from dataclasses

Project description

https://github.com/s-knibbs/dataclasses-jsonschema/workflows/Tox%20tests/badge.svg?branch=master https://badge.fury.io/py/dataclasses-jsonschema.svg Language grade: Python

Please Note: This project is in maintenance mode. I’m currently only making urgent bugfixes.

A library to generate JSON Schema from python 3.7 dataclasses. Python 3.6 is supported through the dataclasses backport. Aims to be a more lightweight alternative to similar projects such as marshmallow & pydantic.

Feature Overview

  • Support for draft-04, draft-06, Swagger 2.0 & OpenAPI 3 schema types
  • Serialisation and deserialisation
  • Data validation against the generated schema
  • APISpec support. Example below:

Installation

~$ pip install dataclasses-jsonschema

For improved validation performance using fastjsonschema, install with:

~$ pip install dataclasses-jsonschema[fast-validation]

Examples

from dataclasses import dataclass

from dataclasses_jsonschema import JsonSchemaMixin


@dataclass
class Point(JsonSchemaMixin):
    "A 2D point"
    x: float
    y: float

Schema Generation

>>> pprint(Point.json_schema())
{
    'description': 'A 2D point',
    'type': 'object',
    'properties': {
        'x': {'format': 'float', 'type': 'number'},
        'y': {'format': 'float', 'type': 'number'}
    },
    'required': ['x', 'y']
}

Data Serialisation

>>> Point(x=3.5, y=10.1).to_dict()
{'x': 3.5, 'y': 10.1}

Deserialisation

>>> Point.from_dict({'x': 3.14, 'y': 1.5})
Point(x=3.14, y=1.5)
>>> Point.from_dict({'x': 3.14, y: 'wrong'})
dataclasses_jsonschema.ValidationError: 'wrong' is not of type 'number'

Generating multiple schemas

from dataclasses_jsonschema import JsonSchemaMixin, SchemaType

@dataclass
class Address(JsonSchemaMixin):
    """Postal Address"""
    building: str
    street: str
    city: str

@dataclass
class Company(JsonSchemaMixin):
    """Company Details"""
    name: str
    address: Address

>>> pprint(JsonSchemaMixin.all_json_schemas(schema_type=SchemaType.SWAGGER_V3))
{'Address': {'description': 'Postal Address',
             'properties': {'building': {'type': 'string'},
                            'city': {'type': 'string'},
                            'street': {'type': 'string'}},
             'required': ['building', 'street', 'city'],
             'type': 'object'},
 'Company': {'description': 'Company Details',
             'properties': {'address': {'$ref': '#/components/schemas/Address'},
                            'name': {'type': 'string'}},
             'required': ['name', 'address'],
             'type': 'object'}}

Custom validation using NewType

from dataclasses_jsonschema import JsonSchemaMixin, FieldEncoder

PhoneNumber = NewType('PhoneNumber', str)

class PhoneNumberField(FieldEncoder):

    @property
    def json_schema(self):
        return {'type': 'string', 'pattern': r'^(\([0-9]{3}\))?[0-9]{3}-[0-9]{4}$'}

JsonSchemaMixin.register_field_encoders({PhoneNumber: PhoneNumberField()})

@dataclass
class Person(JsonSchemaMixin):
    name: str
    phone_number: PhoneNumber

For more examples see the tests

APISpec Plugin

New in v2.5.0

OpenAPI & Swagger specs can be generated using the apispec plugin:

from typing import Optional, List
from dataclasses import dataclass

from apispec import APISpec
from apispec_webframeworks.flask import FlaskPlugin
from flask import Flask, jsonify
import pytest

from dataclasses_jsonschema.apispec import DataclassesPlugin
from dataclasses_jsonschema import JsonSchemaMixin


# Create an APISpec
spec = APISpec(
    title="Swagger Petstore",
    version="1.0.0",
    openapi_version="3.0.2",
    plugins=[FlaskPlugin(), DataclassesPlugin()],
)


@dataclass
class Category(JsonSchemaMixin):
    """Pet category"""
    name: str
    id: Optional[int]

@dataclass
class Pet(JsonSchemaMixin):
    """A pet"""
    categories: List[Category]
    name: str


app = Flask(__name__)


@app.route("/random")
def random_pet():
    """A cute furry animal endpoint.
    ---
    get:
      description: Get a random pet
      responses:
        200:
          content:
            application/json:
              schema: Pet
    """
    pet = get_random_pet()
    return jsonify(pet.to_dict())

# Dependant schemas (e.g. 'Category') are added automatically
spec.components.schema("Pet", schema=Pet)
with app.test_request_context():
    spec.path(view=random_pet)

TODO

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for dataclasses-jsonschema, version 2.14.1
Filename, size File type Python version Upload date Hashes
Filename, size dataclasses_jsonschema-2.14.1-py3-none-any.whl (17.6 kB) File type Wheel Python version py3 Upload date Hashes View
Filename, size dataclasses-jsonschema-2.14.1.tar.gz (28.0 kB) File type Source Python version None Upload date Hashes View

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring DigiCert DigiCert EV certificate Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page