リーダーボードをMomentoで実装する

# npmを使用する場合
% npm install @gomomento/sdk

import { 
  CacheClient, 
  CacheSortedSetPutElementResponse, 
  CacheSortedSetFetchResponse, 
  CreateCache,
  SortedSetOrder
} from "@gomomento/sdk";
import { promises as fs } from "fs";

interface MomentoKeyInfo {
  apiKey: string;
  refreshToken: string;
  validUntil: number;
  restEndpoint: string;
}

// 認証情報をJSONファイルから読み込み
async function loadMomentoKeyInfo(path: string): Promise<MomentoKeyInfo> {
  const data = await fs.readFile(path, "utf8");
  return JSON.parse(data);
}

// SortedSet にスコアを追加
async function updateScoreSortedSet(client: CacheClient, cacheName: string, player: string, score: number): Promise<void> {
  const addResponse = await client.sortedSetPutElement(cacheName, "leaderboard", player, score);

  switch (addResponse.type) {
    case CacheSortedSetPutElementResponse.Success:
      console.log(`Added/updated ${player} with score ${score}`);
      break;
    case CacheSortedSetPutElementResponse.Error:
      console.error(`Failed to add ${player}:`, addResponse.message());
      break;
  }
}

// SortedSet から上位 N 位を取得
async function displayLeaderboard(client: CacheClient, cacheName: string, topN: number): Promise<void> {
  const rangeResponse = await client.sortedSetFetchByRank(
    cacheName,
    "leaderboard",
    {
      startRank: 0,
      endRank: topN - 1,
      order: SortedSetOrder.Descending
    }
  );

  switch (rangeResponse.type) {
    case CacheSortedSetFetchResponse.Hit:
      console.log("Top Leaderboard:");
      const elements = rangeResponse.value();
      elements.forEach((element, index) => {
        console.log(`${index + 1}. ${element.value} - ${element.score}`);
      });
      break;
    case CacheSortedSetFetchResponse.Miss:
      console.log("Leaderboard not found");
      break;
    case CacheSortedSetFetchResponse.Error:
      console.error("Failed to retrieve leaderboard:", rangeResponse.message());
      break;
  }
}

async function main(): Promise<void> {
  // 認証情報load
  const keyInfo = await loadMomentoKeyInfo("./momento_key_info.json");

  // 環境変数に認証情報を設定
  process.env.MOMENTO_API_KEY = keyInfo.apiKey;

  // CacheClient生成
  const cacheClient = await CacheClient.create({
    defaultTtlSeconds: 300,  // 5分間キャッシュ保持
  });

  const cacheName = "my-cache";

  // リーダーボード用のキャッシュ作成
  const createCacheResponse = await cacheClient.createCache(cacheName);
  if (createCacheResponse instanceof CreateCache.Success) {
    console.log("Cache created successfully");
  } else if (createCacheResponse instanceof CreateCache.AlreadyExists) {
    console.log("Cache already exists");
  } else if (createCacheResponse instanceof CreateCache.Error) {
    console.error("Failed to create cache:", createCacheResponse.message());
  }

  // デモ用プレイヤーデータ（スコアは適当）
  const players = [
    { name: "Taro", score: Math.floor(Math.random() * 1000) },
    { name: "Hanako", score: Math.floor(Math.random() * 1000) },
    { name: "Mike", score: Math.floor(Math.random() * 1000) },
    { name: "Syuta", score: Math.floor(Math.random() * 1000) },
    { name: "Hoge", score: Math.floor(Math.random() * 1000) },
  ];

  // 各プレイヤーのスコアを SortedSet に登録
  for (const { name, score } of players) {
    await updateScoreSortedSet(cacheClient, cacheName, name, score);
  }

  // 上位5名のリーダーボードを表示
  await displayLeaderboard(cacheClient, cacheName, 5);

  await cacheClient.close();
}

main().catch((e) => {
  console.error("Error occurred:", e);
});

% npx ts-node sorted_set.ts

Added/updated Taro with score 385
Added/updated Hanako with score 462
Added/updated Mike with score 573
Added/updated Syuta with score 989
Added/updated Hoge with score 590

Top Leaderboard:
1. Syuta - 989
2. Hoge - 590
3. Mike - 573
4. Hanako - 462

const addResponse = await client.sortedSetAdd("leaderboard", player, score);

const rangeResponse = await client.sortedSetRange(
  "leaderboard",
  0,
  topN - 1,
  //降順
  { order: SortedSetRangeOrder.Descending }
);