protected function getHeader()
    {
        ini_set('auto_detect_line_endings', true);
        if (($handle = fopen($this->file, "r")) !== false) {
            $header = fgetcsv($handle, 0, ',');
            static::isHeader($header);

            return $header;
        } else {
            throw new InternalServerErrorException('Could not open uploaded CSV file.');
        }
    }