fastapi_swagger2

Swagger2 support for FastAPI

Reason behind this library:

Few API GW services like Google Cloud API GW still support only Swagger 2.0 spec. Since FastAPI only supports OAS3, it is a challenge. Converting from OAS3 to Swagger 2.0 requires some manual steps which would hinder CI/CD.

Requirements

Python 3.10+

• 0.4.3 - FastAPI >= 0.140.3, < 0.140.7
• 0.4.2 - FastAPI >= 0.140.0, < 0.140.3
• 0.4.1 - FastAPI >= 0.137.2, < 0.140.0
• 0.4.0 - FastAPI >= 0.137.0, <= 0.137.1
• 0.3.5 - FastAPI >= 0.129.0, < 0.137.0
• 0.3.4 - FastAPI >= 0.129.0 (last tested against 0.133.1)
• 0.3.3 - FastAPI >= 0.128.4, <= 0.128.8 (FastAPI has dropped Python 3.9 support since 0.129.1)
• 0.3.2 - FastAPI >= 0.128.0, <= 0.128.3
• 0.3.1 - FastAPI >= 0.123.9, <= 0.127.1 + Pydantic v1/v2 (Since FastAPI 0.126.1, Pydantic v1 is deprecated)
• 0.3.0 - FastAPI >= 0.119.0, <= 0.123.8 + Pydantic v1/v2
• 0.2.7 - FastAPI >= 0.100.0, < 0.119.0 + Pydantic v1/v2
• 0.2.4 - FastAPI >= 0.100.0
• 0.1.1 - FastAPI >= 0.99.0, <= 0.99.1
• 0.0.3 - FastAPI >= 0.79.0, <= 0.98.0

Installation

$ pip install fastapi_swagger2

Development

$ uv sync --extra dev --extra test --extra all

Example

from typing import Union

from fastapi import FastAPI
from fastapi_swagger2 import FastAPISwagger2

app = FastAPI()
FastAPISwagger2(app)


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

This adds following endpoints:

• http://localhost:8000/swagger2.json
• http://localhost:8000/swagger2/docs
• http://localhost:8000/swagger2/redoc

Generate spec for CI/CD

import os

import yaml

from app.main import app

URL = os.environ["CLOUD_RUN_URL"]

app.servers.append(URL)

spec = app.swagger2()
spec['x-google-backend'] = {'address': URL}

print(yaml.dump(spec))

Development

$ uv sync --extra dev --extra test --extra all