SaeTOAuthV2::parseSignedRequest PHP Method

    function parseSignedRequest($signed_request)
    {
        list($encoded_sig, $payload) = explode('.', $signed_request, 2);
        $sig = self::base64decode($encoded_sig);
        $data = json_decode(self::base64decode($payload), true);
        if (strtoupper($data['algorithm']) !== 'HMAC-SHA256') {
            return '-1';
        }
        $expected_sig = hash_hmac('sha256', $payload, $this->client_secret, true);
        return $sig !== $expected_sig ? '-2' : $data;
    }

 /**
  * 授权页
  */
 public function actionCallback()
 {
     // weibo POST
     //从POST过来的signed_request中提取oauth2信息
     if (!empty($_REQUEST["signed_request"])) {
         $o = new SaeTOAuthV2(Yii::app()->params['WB_AKEY'], Yii::app()->params['WB_SKEY']);
         $data = $o->parseSignedRequest($_REQUEST["signed_request"]);
         if ($data == '-2') {
             die('签名错误!');
         } else {
             $_SESSION['oauth2'] = $data;
         }
     }
     //print_r($_SESSION['oauth2']);
     if (empty($_SESSION['oauth2']["user_id"])) {
         //若没有获取到access token，则发起授权请求
         $this->render('auth');
     } else {
         //若已获取到access token，则加载应用信息
         //print_r($_SESSION['oauth2']);
         $c = new SaeTClientV2(Yii::app()->params['WB_AKEY'], Yii::app()->params['WB_SKEY'], $_SESSION['oauth2']['oauth_token'], '');
         Yii::app()->session['api'] = $c;
         $this->redirect('/');
         //setcookie( 'weibojs_'.$o->client_id, http_build_query($_SESSION['oauth2']) );
     }
 }