🖼, 👆 💪 🚮 🌖 📻 🆎 `image/png`, 📣 👈 👆 *➡ 🛠️* 💪 📨 🎻 🎚 (⏮️ 📻 🆎 `application/json`) ⚖️ 🇩🇴 🖼:

```Python hl_lines="19-24  28"
{!../../docs_src/additional_responses/tutorial002.py!}
```

/// note

👀 👈 👆 ✔️ 📨 🖼 ⚙️ `FileResponse` 🔗.

///

/// info

🚥 👆 ✔ 🎏 📻 🆎 🎯 👆 `responses` 🔢, FastAPI 🔜 🤔 📨 ✔️ 🎏 📻 🆎 👑 📨 🎓 (🔢 `application/json`).

///

## Datenklassen als `response_model`

Sie können `dataclasses` auch im Parameter `response_model` verwenden:

```Python hl_lines="1  7-13  19"
{!../../docs_src/dataclasses/tutorial002.py!}
```

Die Datenklasse wird automatisch in eine Pydantic-Datenklasse konvertiert.

Auf diese Weise wird deren Schema in der Benutzeroberfläche der API-Dokumentation angezeigt:

///

## Dataclasses in `response_model`

You can also use `dataclasses` in the `response_model` parameter:

{* ../../docs_src/dataclasses/tutorial002.py hl[1,7:13,19] *}

The dataclass will be automatically converted to a Pydantic dataclass.

This way, its schema will show up in the API docs user interface:

<img src="/img/tutorial/dataclasses/image01.png">

///

## ⌨ 💭 📛

➡️ 👀 ⏮️ 🖼 🔄:

```Python hl_lines="6"
{!../../docs_src/response_status_code/tutorial001.py!}
```

`201` 👔 📟 "✍".

✋️ 👆 🚫 ✔️ ✍ ⚫️❔ 🔠 👉 📟 ⛓.

👆 💪 ⚙️ 🏪 🔢 ⚪️➡️ `fastapi.status`.

```Python hl_lines="1  6"
{!../../docs_src/response_status_code/tutorial002.py!}
```

👫 🏪, 👫 🧑‍🤝‍🧑 🎏 🔢, ✋️ 👈 🌌 👆 💪 ⚙️ 👨‍🎨 📋 🔎 👫:

```

////

//// tab | Python 3.8+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="10"
{!> ../../docs_src/header_param_models/tutorial002.py!}
```

////

If a client tries to send some **extra headers**, they will receive an **error** response.

### Evento `shutdown`

Para adicionar uma função que deve ser executada quando a aplicação estiver encerrando, declare ela com o evento `"shutdown"`:

```Python hl_lines="6"
{!../../docs_src/events/tutorial002.py!}
```

Aqui, a função de manipulação de evento `shutdown` irá escrever uma linha de texto `"Application shutdown"` no arquivo `log.txt`.

/// info | "Informação"

### `shutdown` event

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

{* ../../docs_src/events/tutorial002.py hl[6] *}

Here, the `shutdown` event handler function will write a text line `"Application shutdown"` to a file `log.txt`.

/// info

{!../../docs_src/background_tasks/tutorial001.py!}
```

**FastAPI** 会创建一个 `BackgroundTasks` 类型的对象并作为该参数传入。

## 创建一个任务函数

创建要作为后台任务运行的函数。

它只是一个可以接收参数的标准函数。

它可以是 `async def` 或普通的 `def` 函数，**FastAPI** 知道如何正确处理。

在这种情况下，任务函数将写入一个文件（模拟发送电子邮件）。

由于写操作不使用 `async` 和 `await`，我们用普通的 `def` 定义函数：

```Python hl_lines="6-9"
{!../../docs_src/background_tasks/tutorial001.py!}
```

## 添加后台任务

from inline_snapshot import snapshot

from tests.utils import needs_py39, needs_py310, needs_pydanticv1, needs_pydanticv2


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial002", marks=needs_pydanticv2),
        pytest.param("tutorial002_py310", marks=[needs_py310, needs_pydanticv2]),
        pytest.param("tutorial002_an", marks=needs_pydanticv2),

열거형 `ModelName`의 *열거형 멤버*를 비교할 수 있습니다:

```Python hl_lines="17"
{!../../docs_src/path_params/tutorial005.py!}
```

#### *열거형 값* 가져오기

`model_name.value` 또는 일반적으로 `your_enum_member.value`를 이용하여 실제 값(위 예시의 경우 `str`)을 가져올 수 있습니다:

```Python hl_lines="20"
{!../../docs_src/path_params/tutorial005.py!}
```

/// tip | "팁"

`ModelName.lenet.value`로도 값 `"lenet"`에 접근할 수 있습니다.

///