defspec

Create the OpenAPI spec and document from dataclass, attrs, msgspec, etc.

Why not ...

Note

There are also lots of other projects can generate the OpenAPI document or even validate the data. This project is not intended to replace them.

This project is a legacy of a private initiative. During the development, I discovered that using msgspec could elegantly define and generate the API schema. The OpenAPI component can be utilized to generate the API documentation for various projects. As a result, I made the decision to extract it and transform it into a public project.

You can use this project as a low-level component or a drop-in module when you don't want to introduce too many other dependencies.

Installation

pip install defspec

Examples

• flask: examples/flask
• falcon: examples/falcon

You can run the above examples and open the OpenAPI document in your browser:

• swagger: http://127.0.0.1:8000/openapi/swagger
• redoc: http://127.0.0.1:8000/openapi/redoc
• scalar: http://127.0.0.1:8000/openapi/scalar

Usage

from dataclasses import dataclass
from typing import List

from defspec import OpenAPI


@dataclass
class User:
    name: str
    age: int


openapi = OpenAPI()
openapi.register_route("/", method="get", summary="Hello World")
openapi.register_route(
    "/users", method="post", summary="Get all the user info", response_type=List[User]
)

# get the OpenAPI spec
print(openapi.to_dict())
# get the OpenAPI spec bytes
with open("openapi.json", "wb") as f:
    f.write(openapi.to_json())

# serve as a HTTP server
openapi.serve_as_http_daemon(port=8000, run_in_background=True)