**FastAPI** los utiliza internamente para lograr esto.

///

## Dependencias con `yield` y `HTTPException` { #dependencies-with-yield-and-httpexception }

Viste que puedes usar dependencias con `yield` y tener bloques `try` que intentan ejecutar algo de código y luego ejecutar código de salida después de `finally`.

from fastapi import Depends, FastAPI, Header, HTTPException

app = FastAPI()


async def verify_token(x_token: Annotated[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: Annotated[str, Header()]):
    if x_key != "fake-super-secret-key":
        raise HTTPException(status_code=400, detail="X-Key header invalid")

**FastAPI**는 이를 내부적으로 컨텍스트 관리자를 사용하여 구현합니다.

///

## `yield`와 `HTTPException`를 사용하는 의존성

`yield`와 `try` 블록이 있는 의존성을 사용하여 예외를 처리할 수 있다는 것을 알게 되었습니다.

같은 방식으로, `yield` 이후의 종료 코드에서 `HTTPException`이나 유사한 예외를 발생시킬 수 있습니다.

/// tip | 팁

이는 다소 고급 기술이며, 대부분의 경우 경로 연산 함수 등 나머지 애플리케이션 코드 내부에서 예외 (`HTTPException` 포함)를 발생시킬 수 있으므로 실제로는 필요하지 않을 것입니다.

하지만 필요한 경우 사용할 수 있습니다. 🤓

///

from fastapi import FastAPI, HTTPException

app = FastAPI()

items = {"foo": "The Foo Wrestlers"}


@app.get("/items/{item_id}")
async def read_item(item_id: str):
    if item_id not in items:
        raise HTTPException(status_code=404, detail="Item not found")

from fastapi import Depends, FastAPI, Header, HTTPException


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

    raw_body = await request.body()
    try:
        data = yaml.safe_load(raw_body)
    except yaml.YAMLError:
        raise HTTPException(status_code=422, detail="Invalid YAML")
    try:
        item = Item.parse_obj(data)
    except ValidationError as e:
        raise HTTPException(status_code=422, detail=e.errors())

    raw_body = await request.body()
    try:
        data = yaml.safe_load(raw_body)
    except yaml.YAMLError:
        raise HTTPException(status_code=422, detail="Invalid YAML")
    try:
        item = Item.model_validate(data)
    except ValidationError as e:
        raise HTTPException(status_code=422, detail=e.errors(include_url=False))

from fastapi import FastAPI, HTTPException

app = FastAPI()

items = {"foo": "The Foo Wrestlers"}


@app.get("/items-header/{item_id}")
async def read_item_header(item_id: str):
    if item_id not in items:
        raise HTTPException(
            status_code=404,
            detail="Item not found",
            headers={"X-Error": "There goes my error"},
        )

from fastapi import Depends, FastAPI, Header, HTTPException


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

from fastapi import FastAPI, HTTPException
from fastapi.exception_handlers import (
    http_exception_handler,
    request_validation_exception_handler,
)
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException

app = FastAPI()


@app.exception_handler(StarletteHTTPException)
async def custom_http_exception_handler(request, exc):
    print(f"OMG! An HTTP error!: {repr(exc)}")