May 2019
Intermediate to advanced
464 pages
9h 22m
Japanese
Content preview from Node.jsデザインパターン 第2版
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214
7
章 モジュールの接続
7.2
モジュール接続のためのパターン
依存関係と結合度に関する基本を説明しましたから、より実際的な概念について掘り下げていきま
しょう。この節では、モジュール接続のパターンのうち主なものを示します。特に、アプリケーション
でもっとも重要なタイプの依存関係である、ステートをもつインスタンスとの接続に焦点を合わせます。
7.2.1
依存関係のハードコーディング
2
つのモジュール間のもっともありきたり
4 4 4 4 4
の関係から分析を開始しましょう。「ハードコードされた依
存」です。
Node
では、クライアントとなるモジュールが別のモジュールを
require()
を使って明示的
に読み込んだときにこの依存が成立します。この節で説明するとおり、この方法によるモジュール依存
関係の構築は単純で効果的ですが、ステートをもつインスタンスへの依存をコードに書き込む場合に
は、モジュールの再利用性が制限されてしまうため、また別の注意が必要です
。
7.2.1.1
依存関係をハードコーディングした認証サーバの構築
分析の出発点として、まず図7-1に示したような構造を見てみましょう。
AuthController
（認証コントローラ）
AuthService
（認証サービス）
DB
（データベース）
図7-1 単純な認証システムの構造
図7-1は、レイヤー構造の典型例を示したもので、単純な認証システムの構造を表しています。
AuthController
はクライアントからの入力を受け付け、リクエストからログイン情報を抽 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.