在课堂上运行 fastapi答案

【问题标题】：Running fastapi within class在课堂上运行 fastapi
【发布时间】：2021-06-10 01:11:14
【问题描述】：

import uvicorn
from fastapi import FastAPI

# 2. Create the app object
app = FastAPI()

# 3. Index route, opens automatically on http://127.0.0.1:8000
class RunModel():
    @app.get('/')
    def index(self):
        return {'message': 'Hello'}

    @app.get('/predict')
    def get_res(self, feat1: float, feat2:float):
        res = feat1 + feat2
        return {'result': f'{res:.4f}'}

run_model = RunModel()
# 5. Run the API with uvicorn
#    Will run on http://127.0.0.1:8000
if __name__ == '__main__':
    uvicorn.run(app, host='127.0.0.1', port=8000)

当我首先运行它时，我得到了错误（在终端而不是浏览器中）422 Unprocessable Entity。接下来是当我访问 http://localhost:8000/docs 时，它似乎希望我为 /predict 路由输入 3 个值，这两个功能符合预期和 self。所以问题是我怎样才能使用这个类结构并且仍然使用fastapi（即忽略self）。

【问题讨论】：

标签： python fastapi

【解决方案1】：

你可以这样做：

from fastapi import FastAPI
import uvicorn

class Settings:
    def __init__(self):
        self.api_version = "v1"
        self.api_name = "my_api"
        self.db = "some db"
        self.logger = "configured logger"
        self.DEBUG = True


class MyApi:
    def __init__(self, settings):
        self.settings = settings
        self._fastapi = FastAPI(
            version=self.settings.api_version,
        )
        self._fastapi.add_api_route(
            path="/",
            endpoint=self.index,
            methods=["GET"]
        )

        self._fastapi.add_api_route(
            path="/predict",
            endpoint=self.get_res,
            methods=["POST"]
        )

    async def index(self):
        if self.settings.DEBUG:
            pass
        return {"message": "Hello"}

    async def get_res(self, feat1: float, feat2: float):
        """
        You are able to access the settings
        """
        res = feat1 + feat2
        return {"result": f"{res:.4f}", "api_version": self.settings.api_version}

    def __getattr__(self, attr):
        if hasattr(self._fastapi, attr):
            return getattr(self._fastapi, attr)
        else:
            raise AttributeError(f"{attr} not exist")

    async def __call__(self, *args, **kwargs):
        return await self._fastapi(*args, **kwargs)


settings = Settings()
app = MyApi(settings)


if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

【讨论】：

【解决方案2】：

使用来自fastapi-utils 的基于类的视图。

使用 InferringRouter 创建一个路由器，然后用cbv 对象装饰类。在类中，您可以使用 router 对象开始创建端点。

import uvicorn
from fastapi import FastAPI
from fastapi_utils.cbv import cbv
from fastapi_utils.inferring_router import InferringRouter


app = FastAPI()
router = InferringRouter()


@cbv(router)
class RunModel:
    @router.get("/")
    def index(self):
        return {"message": "Hello"}

    @router.get("/predict")
    def get_res(self, feat1: float, feat2: float):
        res = feat1 + feat2
        return {"result": f"{res:.4f}"}


app.include_router(router)

【讨论】：