PHP5.1.3版以上支持用curl_getinfo函数来获取请求头
具体需要先设置 curl_setopt($ch, CURLINFO_HEADER_OUT, true);
然后在请求发生后用 curl_getinfo($ch, CURLINFO_HEADER_OUT);

function curlRequest($url, $params = array(), $is_post = false, $time_out = 10, $header=array())
    {
        $str_cookie = isset($ext_params['str_cookie']) ? $ext_params['str_cookie'] : '';$ch = curl_init();//初始化curl
        curl_setopt($ch, CURLOPT_URL, $url);//抓取指定网页
        curl_setopt($ch, CURLOPT_HEADER, 0);//设置是否返回response header
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上

        //当需要通过curl_getinfo来获取发出请求的header信息时，该选项需要设置为true
        curl_setopt($ch, CURLINFO_HEADER_OUT, true);

        curl_setopt($ch, CURLOPT_TIMEOUT, $time_out);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $time_out);
        curl_setopt($ch, CURLOPT_POST, $is_post);

        if ($is_post) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
        }

        if ($str_cookie) {
            curl_setopt($ch, CURLOPT_COOKIE, $str_cookie);
        }

        if ($header) {
            curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
        }

        $response = curl_exec($ch);

　　　　　//打印请求的header信息
        $request_header = curl_getinfo( $ch, CURLINFO_HEADER_OUT);
        print_r($request_header);

        curl_close($ch);

        return $response;
    }