feat: implement caching for file info, add rate limiting, and enhance upload handling with retry logic

src/utils/cache.ts

@@ -0,0 +1,81 @@
+// Simple in-memory cache with TTL support
+interface CacheEntry<T> {
+  value: T;
+  expiresAt: number;
+}
+
+class Cache<T> {
+  private store = new Map<string, CacheEntry<T>>();
+  private ttlMs: number;
+
+  constructor(ttlSeconds: number = 3600) {
+    this.ttlMs = ttlSeconds * 1000;
+  }
+
+  set(key: string, value: T): void {
+    this.store.set(key, {
+      value,
+      expiresAt: Date.now() + this.ttlMs,
+    });
+  }
+
+  get(key: string): T | null {
+    const entry = this.store.get(key);
+    if (!entry) return null;
+
+    if (Date.now() > entry.expiresAt) {
+      this.store.delete(key);
+      return null;
+    }
+
+    return entry.value;
+  }
+
+  has(key: string): boolean {
+    return this.get(key) !== null;
+  }
+
+  delete(key: string): void {
+    this.store.delete(key);
+  }
+
+  clear(): void {
+    this.store.clear();
+  }
+
+  size(): number {
+    return this.store.size;
+  }
+
+  // Cleanup expired entries
+  cleanup(): number {
+    let removed = 0;
+    const now = Date.now();
+
+    for (const [key, entry] of this.store.entries()) {
+      if (now > entry.expiresAt) {
+        this.store.delete(key);
+        removed++;
+      }
+    }
+
+    return removed;
+  }
+}
+
+// File info cache (1 hour TTL)
+export const fileInfoCache = new Cache<{
+  file_size: number;
+  mime_type: string;
+  file_path: string;
+}>(3600);
+
+// Cleanup expired cache entries every 5 minutes
+setInterval(() => {
+  const removed = fileInfoCache.cleanup();
+  if (removed > 0) {
+    console.log(`Cleaned up ${removed} expired cache entries`);
+  }
+}, 5 * 60 * 1000);
+
+export { Cache };