Initial commit

lib/cache/index.ts

@@ -0,0 +1,151 @@
+import { logger } from "../utils/logger";
+
+export interface CacheOptions {
+  ttl?: number; // 生存时间（毫秒）
+  maxSize?: number; // 最大缓存项数
+}
+
+export interface CacheEntry<T> {
+  value: T;
+  timestamp: number;
+  ttl: number;
+}
+
+class Cache {
+  private cache = new Map<string, CacheEntry<unknown>>();
+  private maxSize: number;
+  private defaultTtl: number;
+
+  constructor(options: CacheOptions = {}) {
+    this.maxSize = options.maxSize || 1000;
+    this.defaultTtl = options.ttl || 5 * 60 * 1000; // 默认5分钟
+  }
+
+  set<T>(key: string, value: T, ttl?: number): void {
+    // 如果缓存已满，删除最旧的项
+    if (this.cache.size >= this.maxSize) {
+      this.evictOldest();
+    }
+
+    const entry: CacheEntry<T> = {
+      value,
+      timestamp: Date.now(),
+      ttl: ttl || this.defaultTtl,
+    };
+
+    this.cache.set(key, entry);
+    logger.debug("Cache set", { key, ttl: entry.ttl });
+  }
+
+  get<T>(key: string): T | null {
+    const entry = this.cache.get(key) as CacheEntry<T> | undefined;
+
+    if (!entry) {
+      logger.debug("Cache miss", { key });
+      return null;
+    }
+
+    // 检查是否过期
+    if (Date.now() - entry.timestamp > entry.ttl) {
+      this.cache.delete(key);
+      logger.debug("Cache expired", { key });
+      return null;
+    }
+
+    logger.debug("Cache hit", { key });
+    return entry.value;
+  }
+
+  has(key: string): boolean {
+    const entry = this.cache.get(key);
+    if (!entry) return false;
+
+    // 检查是否过期
+    if (Date.now() - entry.timestamp > entry.ttl) {
+      this.cache.delete(key);
+      return false;
+    }
+
+    return true;
+  }
+
+  delete(key: string): boolean {
+    const deleted = this.cache.delete(key);
+    if (deleted) {
+      logger.debug("Cache deleted", { key });
+    }
+    return deleted;
+  }
+
+  clear(): void {
+    this.cache.clear();
+    logger.info("Cache cleared");
+  }
+
+  size(): number {
+    return this.cache.size;
+  }
+
+  private evictOldest(): void {
+    let oldestKey: string | null = null;
+    let oldestTime = Date.now();
+
+    for (const [key, entry] of this.cache.entries()) {
+      if (entry.timestamp < oldestTime) {
+        oldestTime = entry.timestamp;
+        oldestKey = key;
+      }
+    }
+
+    if (oldestKey) {
+      this.cache.delete(oldestKey);
+      logger.debug("Cache evicted oldest", { key: oldestKey });
+    }
+  }
+
+  // 清理过期项
+  cleanup(): void {
+    const now = Date.now();
+    let cleanedCount = 0;
+
+    for (const [key, entry] of this.cache.entries()) {
+      if (now - entry.timestamp > entry.ttl) {
+        this.cache.delete(key);
+        cleanedCount++;
+      }
+    }
+
+    if (cleanedCount > 0) {
+      logger.info("Cache cleanup completed", { cleanedCount });
+    }
+  }
+
+  // 获取缓存统计信息
+  getStats(): {
+    size: number;
+    maxSize: number;
+    hitRate: number;
+    missRate: number;
+  } {
+    return {
+      size: this.cache.size,
+      maxSize: this.maxSize,
+      hitRate: 0, // 需要实现命中率统计
+      missRate: 0, // 需要实现未命中率统计
+    };
+  }
+}
+
+// 创建全局缓存实例
+export const cache = new Cache({
+  maxSize: 1000,
+  ttl: 5 * 60 * 1000, // 5分钟
+});
+
+// 定期清理过期项
+if (typeof window === "undefined") {
+  // 仅在服务器端运行
+  setInterval(() => {
+    cache.cleanup();
+  }, 60 * 1000); // 每分钟清理一次
+}