后端: 添加输入验证中间件

backend/src/middleware/validate.js

@@ -0,0 +1,39 @@
+// 输入验证中间件
+const validate = (schema) => {
+  return (req, res, next) => {
+    const errors = [];
+    
+    for (const [field, rules] of Object.entries(schema)) {
+      const value = req.body[field];
+      
+      if (rules.required && !value) {
+        errors.push(`${field} is required`);
+        continue;
+      }
+      
+      if (rules.type === 'string' && typeof value !== 'string') {
+        errors.push(`${field} must be a string`);
+      }
+      
+      if (rules.type === 'number' && typeof value !== 'number') {
+        errors.push(`${field} must be a number`);
+      }
+      
+      if (rules.minLength && value?.length < rules.minLength) {
+        errors.push(`${field} must be at least ${rules.minLength} characters`);
+      }
+      
+      if (rules.maxLength && value?.length > rules.maxLength) {
+        errors.push(`${field} must be at most ${rules.maxLength} characters`);
+      }
+    }
+    
+    if (errors.length > 0) {
+      return res.status(400).json({ error: errors.join(', ') });
+    }
+    
+    next();
+  };
+};
+
+module.exports = validate;