You can use the same `TestClient` to test WebSockets.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

{* ../../docs_src/app_testing/tutorial002_py310.py hl[27:31] *}

/// note

For more details, check Starlette's documentation for [testing WebSockets](https://www.starlette.dev/testclient/#testing-websocket-sessions).

# WebSocket 테스트하기 { #testing-websockets }

같은 `TestClient`를 사용하여 WebSocket을 테스트할 수 있습니다.

이를 위해 `with` 문에서 `TestClient`를 사용하여 WebSocket에 연결합니다:

{* ../../docs_src/app_testing/tutorial002_py310.py hl[27:31] *}

/// note

자세한 내용은 Starlette의 [WebSocket 테스트](https://www.starlette.dev/testclient/#testing-websocket-sessions) 문서를 확인하세요.

/// info | 信息

要使用表单，首先安装 [`python-multipart`](https://github.com/Kludex/python-multipart)。

确保你创建一个[虚拟环境](../virtual-environments.md)，激活它，然后再安装，例如：

```console
$ pip install python-multipart
```

///

/// note | 注意

自 FastAPI 版本 `0.113.0` 起支持此功能。🤓

///

## 表单的 Pydantic 模型 { #pydantic-models-for-forms }

你只需声明一个 **Pydantic 模型**，其中包含你希望接收的**表单字段**，然后将参数声明为 `Form`：

7.7.0

# 测试 WebSockets { #testing-websockets }

你可以使用同一个 `TestClient` 来测试 WebSockets。

为此，在 `with` 语句中使用 `TestClient` 连接到 WebSocket：

{* ../../docs_src/app_testing/tutorial002_py310.py hl[27:31] *}

/// note | 注意

更多细节请查看 Starlette 的文档：[测试 WebSockets](https://www.starlette.dev/testclient/#testing-websocket-sessions)。

 * API</h2>
 *
 * <p>The successor to Guava's caching API is <a
 * href="https://github.com/ben-manes/caffeine/wiki">Caffeine</a>. Its API is designed to make it a
 * nearly drop-in replacement. Note that it is not available for Android or GWT/J2CL and that it may
 * have <a href="https://github.com/ben-manes/caffeine/wiki/Guava">different (usually better)

  }

  /**
   * Returns a supplier that always supplies {@code instance}.
   *
   * <p><b>Discouraged:</b> Prefer using {@code () -> instance}, but note that lambdas do not have
   * human-readable {@link #toString()} representations and are not serializable. If you need a
   * supplier that is serializable, use {@code (Supplier<T> & Serializable) () -> instance}.
   */

   * CacheBuilder#refreshAfterWrite}.
   *
   * <p><b>Note:</b> <i>all exceptions thrown by this method will be logged and then swallowed</i>.
   *
   * @param key the non-null key whose value should be loaded
   * @param oldValue the non-null old value corresponding to {@code key}
   * @return the future new value associated with {@code key}; <b>must not be null, must not return
   *     null</b>

* 它接收你的应用的每一个**请求**。
* 然后它可以对这个**请求**做一些事情或者执行任何需要的代码。
* 然后它将这个**请求**传递给应用程序的其他部分（某个*路径操作*）处理。
* 之后它获取应用程序生成的**响应**（由某个*路径操作*产生）。
* 它可以对该**响应**做一些事情或者执行任何需要的代码。
* 然后它返回这个**响应**。

/// note | 技术细节

如果你有使用 `yield` 的依赖，依赖中的退出代码会在中间件之后运行。

如果有任何后台任务（会在[后台任务](background-tasks.md)一节中介绍，你稍后会看到），它们会在所有中间件之后运行。

///

## 创建中间件 { #create-a-middleware }

要创建中间件，你可以在函数的顶部使用装饰器 `@app.middleware("http")`。

   * @return the converted instance; <b>must not</b> be null
   * @throws UnsupportedOperationException if backward conversion is not implemented; this should be
   *     very rare. Note that if backward conversion is not only unimplemented but
   *     unimplement<i>able</i> (for example, consider a {@code Converter<Chicken, ChickenNugget>}),
   *     then this is not logically a {@code Converter} at all, and should just implement {@link