diff --git a/index.js b/index.js
index b94d6e5..18d2180 100644
--- a/index.js
+++ b/index.js
@@ -4,6 +4,10 @@ var Session = require('./lib/session');
 var request = require('./lib/request');
 var Tunnel = require('./lib/tunnel');
 
+var authHeader = function() {
+  return request.buildAuthHeader(Session.get());
+}
+
 var exports = module.exports = {
     login: login.login,
     setLoginUrl: login.setLoginUrl,
@@ -13,6 +17,7 @@ var exports = module.exports = {
 
     request: request.request,
     RequestError: request.RequestError,
+    authHeader: authHeader,
 
     Tunnel: Tunnel,
 };
diff --git a/lib/login.js b/lib/login.js
index 28bca0c..23f7f59 100644
--- a/lib/login.js
+++ b/lib/login.js
@@ -136,7 +136,16 @@ var login = function login(options) {
     if (session) {
         wx.checkSession({
             success: function () {
-                options.success(session.userInfo);
+                wx.getUserInfo({
+                    success: function (userResult) {
+                        options.success(userResult.userInfo);
+                    },
+
+                    fail: function () {
+                        Session.clear();
+                        doLogin();
+                    },
+                });
             },
 
             fail: function () {
@@ -157,4 +166,4 @@ module.exports = {
     LoginError: LoginError,
     login: login,
     setLoginUrl: setLoginUrl,
-};
\ No newline at end of file
+};
diff --git a/lib/request.js b/lib/request.js
index e2d5e6a..4b0433e 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -110,4 +110,5 @@ function request(options) {
 module.exports = {
     RequestError: RequestError,
     request: request,
+    buildAuthHeader: buildAuthHeader,
 };
\ No newline at end of file