And then they can try again knowing that it's probably something more similar to `stanleyjobsox` than to `johndoe`.

#### A "professional" attack

And it shows their true commitment to FastAPI and its **community** (you), as they not only want to provide you a **good service** but also want to make sure you have a **good and healthy framework**, FastAPI. 🙇

You might want to try their services and follow their guides:

* <a href="https://docs.platform.sh/languages/python.html?utm_source=fastapi-signup&utm_medium=banner&utm_campaign=FastAPI-signup-June-2023" class="external-link" target="_blank">Platform.sh</a>

In short, if you had dependencies that looked like:

```Python
def my_dep():
    try:
        yield
    except SomeException:
        pass
```

Now you need to make sure you raise again after `except`, just as you would in regular Python:

```Python
def my_dep():
    try:
        yield
    except SomeException:
        raise
```

### Docs

```Python hl_lines="5 6"
{!../../../docs_src/dependencies/tutorial007.py!}
```

!!! tip "豆知識"
    `async`や通常の関数を使用することができます。

    **FastAPI** は、通常の依存関係と同じように、それぞれで正しいことを行います。

## `yield`と`try`を持つ依存関係

`yield`を持つ依存関係で`try`ブロックを使用した場合、その依存関係を使用した際に発生した例外を受け取ることになります。

例えば、途中のどこかの時点で、別の依存関係や*path operation*の中で、データベーストランザクションを「ロールバック」したり、その他のエラーを作成したりするコードがあった場合、依存関係の中で例外を受け取ることになります。

from fastapi import Depends, FastAPI, HTTPException

app = FastAPI()


class InternalError(Exception):
    pass


def get_username():
    try:
        yield "Rick"
    except InternalError:
        print("Oops, we didn't raise again, Britney 😱")


@app.get("/items/{item_id}")
def get_item(item_id: str, username: str = Depends(get_username)):
    if item_id == "portal-gun":
        raise InternalError(

    # to avoid this we let __exit__ run without a capacity limit
    # since we're creating a new limiter for each call, any non-zero limit
    # works (1 is arbitrary)
    exit_limiter = CapacityLimiter(1)
    try:
        yield await run_in_threadpool(cm.__enter__)
    except Exception as e:
        ok = bool(
            await anyio.to_thread.run_sync(
                cm.__exit__, type(e), e, None, limiter=exit_limiter

If you click the lock icon and logout, and then try the same operation again, you will get an HTTP 401 error of:

```JSON
{
  "detail": "Not authenticated"
}
```

### Inactive user

Now try with an inactive user, authenticate with:

User: `alice`

Password: `secret2`

And try to use the operation `GET` with the path `/users/me`.

    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception

    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception

You might want to try their courses:

* <a href="https://training.talkpython.fm/fastapi-courses" class="external-link" target="_blank">Talk Python Training</a>