Yii SOAP Web服务会话ID已重置

我正在使用Yii构建一个SOAP Web服务，并试图通过会话ID管理身份验证，但它在每次请求时都会不断更改
这是我写的代码：

class MessagingController extends CController {
    public function login($username, $password) {
        $user = User::model()->find('username=:username AND password=:password', array(':username' => $username, ':password' => $password));
       if($user) {
            $session = new Session();
            $session->id = Yii::app()->session->sessionID;
            $session->user = $user->id;
            $session->start = date('Y-m-d H:i:s',  time());
            $session->duration = $this->sessionDuration; //Session duration is 1hr.`
            return $session->save() ? 
              $this->generateResponse(0, 'Session initiated successfully.', array('SessionId' => $session->id, 'Timestamp' => $session->start, 'Duration' => $session->duration)) : generateResponse(-1, 'Server error. #S', null);
        }
    return $this->generateResponse(-1, 'Unknown User. #UU', null);
}

}

配置文件：
"session"=>数组("autoStart"=>true，'超时'=>1440，'cookieMode'=>'allow'，)，