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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11.2
パブリッシュ
/
サブスクライブ（
pub/sub
）パターン
395
チャットアプリケーション向け履歴サービスの設計
では、マイクロサービス手法を使って我々の小さなチャットアプリケーションを拡張しましょう。
チャットメッセージをデータベースに保管する履歴サービスを追加し、クライアントの接続時にサー
ビスに照会してチャット履歴すべてを取り出せるようにします。
RabbitMQ
ブローカ（
https://www.
rabbitmq.com
）と
AMQP
を使って、履歴サービスをチャットサーバに結合します。
図11-12にそのためのアーキテクチャを示します。
RabbitMQ
ブローカ
ファンアウト交換器
（
'chat'
）
チャットサーバ
（ポート
8080
）
チャットサーバ
（ポート
8081
）
履歴サービス
クライアントか
らのメッセージ
をパブリッシュ
chat_srv_8080'
chat_srv_8081'
chat_history
図11-12 チャットアプリケーション向け履歴サービスのアーキテクチャ
上のアーキテクチャが示すように、単一のファンアウト交換器を使います。特定のルーティングは必
要ないので、この条件ではこれより複雑な交換器は不要です。次に、チャットサーバのインスタンスご
とにキューをひとつ生成します。これらのキューは排他的です。チャットサーバがオフラインになった
ときに受け取れなかったメッセージを受け取る必要はなく、それは履歴サービスの仕事です。履歴サー
ビスでは保管しているメッセージに対するさらに複雑な照会をするこ
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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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.