"size": "XL"
  }
}
```

#### FastAPIの`HTTPException`とStarletteの`HTTPException` { #fastapis-httpexception-vs-starlettes-httpexception }

**FastAPI**は独自の`HTTPException`を持っています。

また、 **FastAPI**の`HTTPException`エラークラスはStarletteの`HTTPException`エラークラスを継承しています。

唯一の違いは、**FastAPI** の`HTTPException`は`detail`フィールドにJSONに変換可能な任意のデータを受け付けるのに対し、Starletteの`HTTPException`は文字列のみを受け付けることです。

## Use `HTTPException` { #use-httpexception }

To return HTTP responses with errors to the client you use `HTTPException`.

### Import `HTTPException` { #import-httpexception }

{* ../../docs_src/handling_errors/tutorial001_py310.py hl[1] *}

### Raise an `HTTPException` in your code { #raise-an-httpexception-in-your-code }

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

```

## `yield`, `HTTPException`, `except` 및 백그라운드 작업을 사용하는 의존성 { #dependencies-with-yield-httpexception-except-and-background-tasks }

`yield`를 사용하는 의존성은 시간이 지나면서 서로 다른 사용 사례를 다루고 일부 문제를 수정하기 위해 발전해 왔습니다.

FastAPI의 여러 버전에서 무엇이 바뀌었는지 보고 싶다면, 고급 가이드의 [고급 의존성 - `yield`, `HTTPException`, `except` 및 백그라운드 작업을 사용하는 의존성](../../advanced/advanced-dependencies.md#dependencies-with-yield-httpexception-except-and-background-tasks)에서 더 자세히 읽을 수 있습니다.

///

## Dependencies with `yield` and `HTTPException` { #dependencies-with-yield-and-httpexception }

You saw that you can use dependencies with `yield` and have `try` blocks that try to execute some code and then run some exit code after `finally`.

You can also use `except` to catch the exception that was raised and do something with it.

For example, you can raise a different exception, like `HTTPException`.

/// tip

        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return fake_db[item_id]


@app.post("/items/")
async def create_item(item: Item, x_token: Annotated[str, Header()]) -> Item:
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")

    if item_id not in fake_items_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return {"name": fake_items_db[item_id]["name"], "item_id": item_id}


@router.put(
    "/{item_id}",
    tags=["custom"],
    responses={403: {"description": "Operation forbidden"}},
)
async def update_item(item_id: str):
    if item_id != "plumbus":
        raise HTTPException(

    except HTTPException:
        state["except"] = True
        raise
    finally:
        state["finally"] = True


@app.put("/invalid-user/{user_id}")
def put_invalid_user(
    user_id: str, name: str = Body(), db: dict = Depends(get_database)
):
    db[user_id] = name
    raise HTTPException(status_code=400, detail="Invalid user")


@app.put("/user/{user_id}")

    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return fake_db[item_id]


@app.post("/items/")
async def create_item(item: Item, x_token: str = Header()) -> Item:
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")

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