Class.php

   /**
    * Send JSON encoded data to the browser and end all further processing.
    * @method endWithJson
    * @param  array $data A data array.
    * @throws InvalidArgumentException
    * @return void
    */
    private function endWithJson($data)
    {
        if (!is_array($data)) {
            throw new \InvalidArgumentException('Method endWithJson requires a data array as argument.');
        }
        header('Content-type: application/json');
        Yii::app()->end(json_encode($data));
    }