php中用于检测一个地理IP地址是否可用的代码

/********************************************
*
* 函数名：curl_string ($url,$proxy)
* 作 用：检测代理ip地址
* 作 者：李飞麟
* 日 期：2011-11-09
*
********************************************/
function curl_string ($url,$proxy)
{
$user_agent = "mozilla/5.0 (windows; u; windows nt 5.1; zh- cn; rv:1.9.0.5) gecko/2008120122 firefox/3.0.5 firephp/0.2.1";
$ch = curl_init();
curl_setopt ($ch, curlopt_proxy, $proxy);
curl_setopt ($ch, curlopt_url, $url);//设置要访问的ip
curl_setopt ($ch, curlopt_useragent, $user_agent);//模拟用户使用的浏览器
@curl_setopt ( $ch, curlopt_followlocation, 1 ); // 使用自动跳转
curl_setopt ( $ch, curlopt_timeout, 120 ); //设置超时时间
curl_setopt ( $ch, curlopt_autoreferer, 1 ); // 自动设置referer

curl_setopt ($ch, curlopt_cookiejar, 'c:\cookie.txt');
curl_setopt ($ch, curlopt_header, 1);
curl_setopt ($ch, curlopt_returntransfer, 1);
curl_setopt ($ch, curlopt_followlocation, 1);
curl_setopt ($ch, curlopt_timeout, 10);
$result = curl_exec($ch);
// check if any error occured
if( $result === false)
{
error_log(date("h:i:s") . ' curl 失败: ' . curl_error($ch) ." -- ". $proxy."\n", 3, mymedia.'/log/'.date('y-m-d').'_err.log');
}else{
error_log(date("h:i:s") . ' curl 成功: ' . $proxy."\n", 3, mymedia.'/log/'.date('y-m-d').'_ok.log');
}
curl_close($ch);
return $result;
}