php获取访问者ip

/**
* 获取访问者IP
*
*/
public static function get_client_ip() {
if (getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')) {
$CLIENT_IP = getenv('HTTP_CLIENT_IP');
} elseif (getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) {
$CLIENT_IP = getenv('HTTP_X_FORWARDED_FOR');
} elseif (getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {
$CLIENT_IP = getenv('REMOTE_ADDR');
} elseif (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {
$CLIENT_IP = $_SERVER['REMOTE_ADDR'];
}
return $CLIENT_IP;
}

function get_onlineip() {
$ch = curl_init('http://www.ip138.com/ip2city.asp');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$a  = curl_exec($ch);
preg_match('/\[(.*)\]/', $a, $ip);
return $ip[1];
}