refactor

@@ -16,7 +16,7 @@ module.exports = (req, res, next) => {
 
     let loginPage = helpers.urlFormat('/passport/login', {refer: req.fullUrl()});
 
-    if (_.isEmpty(req.user) || !req.user.uid || !req.user.uid.session) {
+    if (_.isEmpty(req.user) || !req.user.uid.isValid()) {
         if (req.xhr) {
             return res.json({
                 code: 400,

@@ -4,6 +4,7 @@
  */
 const headerModel = require('../models/header');
 const logger = global.yoho.logger;
+const helpers = global.yoho.helpers;
 
 const forceNoCache = (res) => {
     if (res) {
@@ -48,6 +49,15 @@ exports.serverError = () => {
 
         logger.error(`error at path: ${req.url}`);
         logger.error(err);
+
+        if (err && err.code === 401) {
+            if (req.xhr) {
+                return res.json(err);
+            } else {
+                return res.redirect(helpers.urlFormat('/signin.html', {refer: req.fullUrl()}));
+            }
+        }
+
         if (!res.headersSent) {
             if (req.xhr) {
                 return res.status(500).json({

@@ -31,7 +31,10 @@ module.exports = () => {
                     return this.uid;
                 },
                 uid: cookie.getUid(req),
-                session: req.cookies._SESSSION
+                session: req.cookies._SESSION,
+                isValid() {
+                    return this.uid && this.session;
+                }
             };
         }