php獲取真實IP方法

/**
 * 读取真实IP方法
 */
function getRealIp()
{
    foreach ([
        'HTTP_CLIENT_IP',
        'HTTP_X_FORWARDED_FOR',
        'HTTP_X_FORWARDED',
        'HTTP_X_CLUSTER_CLIENT_IP',
        'HTTP_FORWARDED_FOR',
        'HTTP_FORWARDED',
        'REMOTE_ADDR',
    ] as $key) {
        if (array_key_exists($key, $_SERVER)) {
            foreach (explode(',', $_SERVER[$key]) as $ip) {
                $ip = trim($ip);
                //会过滤掉保留地址和私有地址段的IP，例如 127.0.0.1会被过滤
                //也可以修改成正则验证IP
                if ((bool) filter_var($ip, FILTER_VALIDATE_IP,
                    FILTER_FLAG_IPV4 |
                    FILTER_FLAG_NO_PRIV_RANGE |
                    FILTER_FLAG_NO_RES_RANGE)) {
                    return $ip;
                }
            }
        }
    }
    return false;
}