* 데이터 변환
* 데이터 검증
* 자동 문서화

## 특별한 타입과 검증

`str`, `int`, `float` 등과 같은 단일 타입과는 별개로, `str`을 상속하는 더 복잡한 단일 타입을 사용할 수 있습니다.

모든 옵션을 보려면, <a href="https://docs.pydantic.dev/latest/concepts/types/" class="external-link" target="_blank">Pydantic's exotic types</a> 문서를 확인하세요. 다음 장에서 몇가지 예제를 볼 수 있습니다.

예를 들어 `Image` 모델 안에 `url` 필드를 `str` 대신 Pydantic의 `HttpUrl`로 선언할 수 있습니다:

    app = FastAPI()


    def write_notification(email: str, message=""):
        with open("log.txt", mode="w") as email_file:
            content = f"notification for {email}: {message}"
            email_file.write(content)


    @app.post("/send-notification/{email}")
    async def send_notification(email: str, background_tasks: BackgroundTasks):

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

def get_items(item_a: str, item_b: int, item_c: float, item_d: bool, item_e: bytes):

	CodeChallengeMethodsSupported    []string `json:"code_challenge_methods_supported,omitempty"`
}

func parseDiscoveryDoc(ustr string) (DiscoveryDoc, error) {
	d := DiscoveryDoc{}
	req, err := http.NewRequest(http.MethodGet, ustr, nil)
	if err != nil {
		return d, err
	}
	clnt := http.Client{
		Transport: http.DefaultTransport,
	}
	resp, err := clnt.Do(req)
	if err != nil {

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[str | None, Query(min_length=3, max_length=50)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(alias="item-query")] = None):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Union[str, None] = Query(default=None, alias="item-query")):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Union

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: int = Path(title="The ID of the item to get"),
    q: Union[str, None] = Query(default=None, alias="item-query"),
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

Wenn es keinen `Authorization`-Header sieht, oder der Wert keinen `Bearer `-Token hat, antwortet es direkt mit einem 401-Statuscode-Error (`UNAUTHORIZED`).

Sie müssen nicht einmal prüfen, ob der Token existiert, um einen Fehler zurückzugeben. Seien Sie sicher, dass Ihre Funktion, wenn sie ausgeführt wird, ein `str` in diesem Token enthält.