后端: 添加缓存中间件

backend/src/middleware/cache.js

@@ -0,0 +1,28 @@
+// 简单缓存中间件
+const cache = new Map();
+
+const cacheMiddleware = (req, res, next) => {
+  if (req.method !== 'GET') {
+    return next();
+  }
+  
+  const key = req.originalUrl;
+  
+  if (cache.has(key)) {
+    const { data, expiry } = cache.get(key);
+    if (Date.now() < expiry) {
+      return res.json(data);
+    }
+    cache.delete(key);
+  }
+  
+  const originalJson = res.json.bind(res);
+  res.json = (data) => {
+    cache.set(key, { data, expiry: Date.now() + 60000 }); // 1分钟缓存
+    return originalJson(data);
+  };
+  
+  next();
+};
+
+module.exports = cacheMiddleware;