function getHeader($ch, $header)
    {
        $i = strpos($header, ':');
        if (!empty($i)) {
            $key = str_replace('-', '_', strtolower(substr($header, 0, $i)));
            $value = trim(substr($header, $i + 2));
            $this->http_header[$key] = $value;
        }
        return strlen($header);
    }