## Details zum `Request`-Objekt

Da **FastAPI** unter der Haube eigentlich **Starlette** ist, mit einer Ebene von mehreren Tools darüber, können Sie Starlette's <a href="https://www.starlette.io/requests/" class="external-link" target="_blank">`Request`</a>-Objekt direkt verwenden, wenn Sie es benötigen.

# 事件：启动 - 关闭

**FastAPI** 支持定义在应用启动前，或应用关闭后执行的事件处理器（函数）。

事件函数既可以声明为异步函数（`async def`），也可以声明为普通函数（`def`）。

/// warning | "警告"

**FastAPI** 只执行主应用中的事件处理器，不执行[子应用 - 挂载](sub-applications.md){.internal-link target=_blank}中的事件处理器。

///

## `startup` 事件

使用 `startup` 事件声明 `app` 启动前运行的函数：

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

本例中，`startup` 事件处理器函数为项目数据库（只是**字典**）提供了一些初始值。

    * You can also add [`Security` dependencies with `scopes`](../advanced/security/oauth2-scopes.md){.internal-link target=_blank}.

/// tip

  // must contain a non-empty list.
  // +optional
  optional bool clusterScope = 4;

  // `namespaces` is a list of target namespaces that restricts
  // matches.  A request that specifies a target namespace matches
  // only if either (a) this list contains that target namespace or
  // (b) this list contains "*".  Note that "*" matches any
  // specified namespace but does not match a request that _does

    * Você também pode adicionar [dependências de `Segurança` com `scopes`](../advanced/security/oauth2-scopes.md){.internal-link target=_blank}.

/// tip | "Dica"

  // must contain a non-empty list.
  // +optional
  optional bool clusterScope = 4;

  // `namespaces` is a list of target namespaces that restricts
  // matches.  A request that specifies a target namespace matches
  // only if either (a) this list contains that target namespace or
  // (b) this list contains "*".  Note that "*" matches any
  // specified namespace but does not match a request that _does

Il y a un chapitre entier ici dans la documentation à ce sujet, vous pouvez le lire sur [Réponses supplémentaires dans OpenAPI](additional-responses.md){.internal-link target=_blank}.

## OpenAPI supplémentaire

Lorsque vous déclarez un *chemin* dans votre application, **FastAPI** génère automatiquement les métadonnées concernant ce *chemin* à inclure dans le schéma OpenAPI.

///

/// info

👉 🖼 👥 ⚙️ 💭 🛃 🎚 `X-Key` & `X-Token`.

✋️ 🎰 💼, 🕐❔ 🛠️ 💂‍♂, 👆 🔜 🤚 🌖 💰 ⚪️➡️ ⚙️ 🛠️ [💂‍♂ 🚙 (⏭ 📃)](../security/index.md){.internal-link target=_blank}.

///

## 🔗 ❌ & 📨 💲

👆 💪 ⚙️ 🎏 🔗 *🔢* 👆 ⚙️ 🛎.

### 🔗 📄

👫 💪 📣 📨 📄 (💖 🎚) ⚖️ 🎏 🎧-🔗:

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

    * 🐍 `datetime.timedelta`.
    * 📨 & 📨 🔜 🎨 `float` 🌐 🥈.
    * Pydantic ✔ 🎦 ⚫️ "💾 8️⃣6️⃣0️⃣1️⃣ 🕰 ➕ 🔢", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">👀 🩺 🌅 ℹ</a>.
* `frozenset`:
    * 📨 &amp; 📨, 😥 🎏 `set`:
        * 📨, 📇 🔜 ✍, ❎ ❎ &amp; 🏭 ⚫️ `set`.
        * 📨, `set` 🔜 🗜 `list`.
        * 🏗 🔗 🔜 ✔ 👈 `set` 💲 😍 (⚙️ 🎻 🔗 `uniqueItems`).

## Return a `Response` directly

You can also create cookies when returning a `Response` directly in your code.

To do that, you can create a response as described in [Return a Response Directly](response-directly.md){.internal-link target=_blank}.

Then set Cookies in it, and then return it:

```Python hl_lines="10-12"
{!../../docs_src/response_cookies/tutorial001.py!}
```

/// tip