FASTAPI 시작하기 (4) - Dependecy Injection

오늘은 fast api 기능 중 하나인
Dependency Injection을 활용해서 코드의 재활용을 향상 시켜 보겠다.

dependency injection으로 코드 재활용 하기

아래의 코드는 common_parameter라는 함수를
read_items과 read_users라는 함수에서 재활용 하는 코드이다

from typing import Optional
from fastapi import FastAPI, Depends

app = FastAPI()

async def common_parameter(q: Optional[str] = None, skip: int = 0, limit: int = 100):
    return {'q' : q, 'skip' : skip, 'limit' : limit}


@app.get('/items/')
async def read_items(common: dict = Depends(common_parameter)):
    return common

@app.get('/users/')
async def read_users(common: dict = Depends(common_parameter)):
    return common

class 재활용하기

# class Dependency Injection
from typing import Optional
from fastapi import FastAPI, Depends

app = FastAPI()

class CommonParam:
    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit

@app.get("/items/")
async def read_items(common: CommonParam = Depends(CommonParam)):
    response = dict()
    if common.q:
        response.update({"q" : common.q})
    return response

토큰 검증함수도 재활용 할 수 있다.

from fastapi import Depends, FastAPI, Header, HTTPException

app = FastAPI()


async def verify_token(x_token: str = Header(...)):
    if x_token != "fake-super-secret-token":
        raise HTTPException(status_code=400, detail="X-Token header invalid")


async def verify_key(x_key: str = Header(...)):
    if x_key != "fake-super-secret-key":
        raise HTTPException(status_code=400, detail="X-Key header invalid")
    return x_key



@app.get("/items/", dependencies=[Depends(verify_token), Depends(verify_key)])
async def read_items():
    return [{"item": "Foo"}, {"item": "Bar"}]