Çok basit bir örneğe bakalım. Şimdilik o kadar basit olacak ki pek işe yaramayacak.

Ama bu sayede **Dependency Injection** sisteminin nasıl çalıştığına odaklanabiliriz.

### Bir dependency (bağımlılık) veya "dependable" Oluşturun { #create-a-dependency-or-dependable }

Önce dependency'e odaklanalım.

Bu, bir *path operation function*'ın alabileceği parametrelerin aynısını alabilen basit bir fonksiyondur:

### Bir `Enum` Sınıfı Oluşturalım { #create-an-enum-class }

`Enum`'u import edin ve `str` ile `Enum`'dan miras alan bir alt sınıf oluşturun.

	// Empirically (at least on the Windows Server 2013 builder),
	// the kernel is arbitrarily okay with < 248 bytes. That
	// matches what the docs above say:
	// "When using an API to create a directory, the specified
	// path cannot be so long that you cannot append an 8.3 file
	// name (that is, the directory name cannot exceed MAX_PATH
	// minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
	//

    }

    @Test
    public void test_AllHttpMethodFactories() {
        // ## Test that all factory methods create requests with correct methods ##

        // ## Act & Assert ##
        assertEquals(Method.GET, Curl.get("http://test.com").method());
        assertEquals(Method.POST, Curl.post("http://test.com").method());

 * easier.
 *
 * @author Jesse Wilson
 * @author Luke Sandberg
 * @since 9.0 (in 1.0 as {@code com.google.common.base.Service})
 */
@DoNotMock("Create an AbstractIdleService")
@J2ktIncompatible
@GwtIncompatible
public interface Service {
  /**
   * If the service state is {@link State#NEW}, this initiates service startup and returns

      if (result) {
        executionList.execute();
      }
      return result;
    }

    /**
     * Following the contract of {@link AbstractQueuedSynchronizer} we create a private subclass to
     * hold the synchronizer. This synchronizer is used to implement the blocking and waiting calls
     * as well as to handle state changes in a thread-safe manner. The current state of the future

///

## Update the dependencies { #update-the-dependencies }

Now we are going to update our dependencies.

We want to get the `current_user` *only* if this user is active.

So, we create an additional dependency `get_current_active_user` that in turn uses `get_current_user` as a dependency.

Both of these dependencies will just return an HTTP error if the user doesn't exist, or if is inactive.

```

</div>

Он также включен при установке набора `all` с:

<div class="termy">

```console
$ pip install "fastapi[all]"
---> 100%
```

</div>

### Создание объекта `Settings` { #create-the-settings-object }

Импортируйте `BaseSettings` из Pydantic и создайте подкласс, очень похожий на Pydantic‑модель.

* `description`: タグの短い説明の `str`。Markdownを含められ、ドキュメントUIに表示されます。
* `externalDocs`: 外部ドキュメントを説明する `dict`。以下を含みます:
    * `description`: 外部ドキュメントの短い説明の `str`。
    * `url` (**必須**): 外部ドキュメントのURLの `str`。

### タグのメタデータの作成 { #create-metadata-for-tags }

`users` と `items` のタグを使った例で試してみましょう。

タグのメタデータを作成し、それを `openapi_tags` パラメータに渡します:

{* ../../docs_src/metadata/tutorial004_py310.py hl[3:16,18] *}

もちろん、これは最適な方法ではありませんし、本番環境で使うことはないでしょう。

本番環境では、上記の方法のいずれかの選択肢を採用することになるでしょう。

しかし、これはWebSocketsのサーバーサイドに焦点を当て、動作する例を示す最も簡単な方法です。

{* ../../docs_src/websockets_/tutorial001_py310.py hl[2,6:38,41:43] *}

## `websocket` を作成する { #create-a-websocket }

**FastAPI** アプリケーションで、`websocket` を作成します。

{* ../../docs_src/websockets_/tutorial001_py310.py hl[1,46:47] *}

/// note | 技術詳細

`from starlette.websockets import WebSocket` を使用しても構いません.