public function index(Auth $auth)
 {
     if (empty($_SESSION['logged_user'])) {
         $auth->authorize($to = null, $scope = 'snsapi_userinfo', $state = 'STATE');
         $user = $auth->user();
         Session::put('logged_user', $user->openid);
         // 跳转到其它授权才能访问的页面
     }
 }
 public function callback(Request $request, Guard $auth, Auth $wxAuth)
 {
     $redirectTo = $request->query('redirectTo', '/');
     $profile = $wxAuth->user();
     $data = $profile->all();
     $user = $auth->user();
     try {
         $alias = $user->aliases()->where('provider', 'wechat')->where('type', 'openid')->firstOrFail();
         if ($data['openid'] != $alias->alias) {
             return response('Forbidden.', 403);
         } else {
             $alias->data = $profile->toJson();
             $alias->save();
         }
     } catch (ModelNotFoundException $e) {
         $user->aliases()->create(['user_id' => $user->id, 'provider' => 'wechat', 'alias' => $data['openid'], 'type' => 'openid', 'data' => $profile->toJson()]);
     }
     $request->session()->put('openid', $data['openid']);
     return redirect($redirectTo);
 }