diff --git a/backend/server.js b/backend/server.js
index 8303948..dffe7ab 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -2716,45 +2716,12 @@ app.get('/api/files/download-url', authMiddleware, async (req, res) => {
   }
 });
 
-// 辅助函数：构建 S3 配置（与 OssStorageClient.buildConfig 保持一致）
+// 辅助函数：构建 S3 配置（复用 OssStorageClient.buildConfig）
 function buildS3Config(user) {
-  const config = {
-    region: user.oss_region || 'us-east-1',
-    credentials: {
-      accessKeyId: user.oss_access_key_id,
-      secretAccessKey: user.oss_access_key_secret
-    }
-  };
-
-  // 阿里云 OSS
-  if (user.oss_provider === 'aliyun') {
-    config.region = user.oss_region || 'oss-cn-hangzhou';
-    if (user.oss_endpoint) {
-      config.endpoint = user.oss_endpoint;
-    } else {
-      // 默认 endpoint 格式：https://oss-{region}.aliyuncs.com
-      config.endpoint = `https://oss-${config.region.replace('oss-', '')}.aliyuncs.com`;
-    }
-  }
-  // 腾讯云 COS
-  else if (user.oss_provider === 'tencent') {
-    config.region = user.oss_region || 'ap-guangzhou';
-    if (user.oss_endpoint) {
-      config.endpoint = user.oss_endpoint;
-    } else {
-      // 默认 endpoint 格式：https://cos.{region}.myqcloud.com
-      config.endpoint = `https://cos.${config.region}.myqcloud.com`;
-    }
-  }
-  // AWS S3 或其他兼容服务
-  else {
-    if (user.oss_endpoint) {
-      config.endpoint = user.oss_endpoint;
-    }
-    // AWS 使用默认 endpoint，无需额外配置
-  }
-
-  return config;
+  // 创建临时 OssStorageClient 实例并复用其 buildConfig 方法
+  const { OssStorageClient } = require('./storage');
+  const tempClient = new OssStorageClient(user);
+  return tempClient.buildConfig();
 }
 
 // 辅助函数：清理文件名
@@ -2966,7 +2933,6 @@ app.get('/api/files/download', authMiddleware, async (req, res) => {
 app.post('/api/upload/generate-tool', authMiddleware, async (req, res) => {
   try {
     // 生成新的API密钥（32位随机字符串）
-    const crypto = require('crypto');
     const newApiKey = crypto.randomBytes(16).toString('hex');
 
     // 更新用户的upload_api_key
@@ -3001,7 +2967,6 @@ app.get('/api/upload/download-tool', authMiddleware, async (req, res) => {
     console.log(`[上传工具] 用户 ${req.user.username} 请求下载上传工具`);
 
     // 生成新的API密钥
-    const crypto = require('crypto');
     const newApiKey = crypto.randomBytes(16).toString('hex');
 
     // 更新用户的upload_api_key