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;
}