➡️ 💬 👆 ✔️ 🛃 ⚠ `UnicornException` 👈 👆 (⚖️ 🗃 👆 ⚙️) 💪 `raise`.

& 👆 💚 🍵 👉 ⚠ 🌐 ⏮️ FastAPI.

👆 💪 🚮 🛃 ⚠ 🐕‍🦺 ⏮️ `@app.exception_handler()`:

```Python hl_lines="5-7  13-18  24"
{!../../../docs_src/handling_errors/tutorial003.py!}
```

📥, 🚥 👆 📨 `/unicorns/yolo`, *➡ 🛠️* 🔜 `raise` `UnicornException`.

✋️ ⚫️ 🔜 🍵 `unicorn_exception_handler`.

```

### 触发 `HTTPException`

`HTTPException` 是额外包含了和 API 有关数据的常规 Python 异常。

因为是 Python 异常，所以不能 `return`，只能 `raise`。

如在调用*路径操作函数*里的工具函数时，触发了 `HTTPException`，FastAPI 就不再继续执行*路径操作函数*中的后续代码，而是立即终止请求，并把 `HTTPException` 的 HTTP 错误发送至客户端。

在介绍依赖项与安全的章节中，您可以了解更多用 `raise` 异常代替 `return` 值的优势。

本例中，客户端用 `ID` 请求的 `item` 不存在时，触发状态码为 `404` 的异常：

```Python hl_lines="11"

👆 💪 ⚙️ 🎏 🔗 *🔢* 👆 ⚙️ 🛎.

### 🔗 📄

👫 💪 📣 📨 📄 (💖 🎚) ⚖️ 🎏 🎧-🔗:

```Python hl_lines="6  11"
{!../../../docs_src/dependencies/tutorial006.py!}
```

### 🤚 ⚠

👫 🔗 💪 `raise` ⚠, 🎏 😐 🔗:

```Python hl_lines="8  13"
{!../../../docs_src/dependencies/tutorial006.py!}
```

### 📨 💲

& 👫 💪 📨 💲 ⚖️ 🚫, 💲 🏆 🚫 ⚙️.

    !!! tip "팁"
        가능하다면 `Annotated`가 달린 버전을 권장합니다.

    ```Python hl_lines="6  11"
    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### 오류 발생시키기

다음 의존성은 기존 의존성과 동일하게 예외를 `raise`를 일으킬 수 있습니다:

=== "Python 3.9+"

    ```Python hl_lines="10  15"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9  14"

    Note over client,tasks: Can raise exception for dependency, handled after response is sent
    Note over client,operation: Can raise HTTPException and can change the response
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise
        dep -->> handler: Raise HTTPException
        handler -->> client: HTTP error response
        dep -->> dep: Raise other exception
    end

    ```Python hl_lines="68-69  81"
    {!> ../../../docs_src/websockets/tutorial002.py!}
    ```

!!! info
    As this is a WebSocket it doesn't really make sense to raise an `HTTPException`, instead we raise a `WebSocketException`.

    You can use a closing code from the <a href="https://tools.ietf.org/html/rfc6455#section-7.4.1" class="external-link" target="_blank">valid codes defined in the specification</a>.

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="6  11"
    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Raise exceptions

These dependencies can `raise` exceptions, the same as normal dependencies:

=== "Python 3.9+"

    ```Python hl_lines="10  15"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"

### 依存関係の要件

これらはリクエストの要件（ヘッダのようなもの）やその他のサブ依存関係を宣言することができます:

```Python hl_lines="6 11"
{!../../../docs_src/dependencies/tutorial006.py!}
```

### 例外の発生

これらの依存関係は通常の依存関係と同じように、例外を`raise`発生させることができます:

```Python hl_lines="8 13"
{!../../../docs_src/dependencies/tutorial006.py!}
```

### 戻り値

そして、値を返すことも返さないこともできますが、値は使われません。

つまり、すでにどこかで使っている通常の依存関係（値を返すもの）を再利用することができ、値は使われなくても依存関係は実行されます:

    ```Python hl_lines="6  11"
    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Вызов исключений

Зависимости из dependencies могут вызывать исключения с помощью `raise`, как и обычные зависимости:

=== "Python 3.9+"

    ```Python hl_lines="10  15"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9  14"

    ```Python hl_lines="6  11"
    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Exceptions auslösen

Die Abhängigkeiten können Exceptions `raise`n, genau wie normale Abhängigkeiten:

=== "Python 3.9+"

    ```Python hl_lines="10  15"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"