PHP 获取客户端 IP 地址的方法实例代码

/**
 * 获取客户端IP地址
 */
function real_ip()
{
  $ip = $_SERVER[\'REMOTE_ADDR\'];
  if (isset($_SERVER[\'HTTP_X_FORWARDED_FOR\']) && preg_match_all(\'#\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}#s\', $_SERVER[\'HTTP_X_FORWARDED_FOR\'], $matches)) {
    foreach ($matches[0] AS $xip) {
      if (!preg_match(\'#^(10|172\\.16|192\\.168)\\.#\', $xip)) {
        $ip = $xip;
        break;
      }
    }
  } elseif (isset($_SERVER[\'HTTP_CLIENT_IP\']) && preg_match(\'/^([0-9]{1,3}\\.){3}[0-9]{1,3}$/\', $_SERVER[\'HTTP_CLIENT_IP\'])) {
    $ip = $_SERVER[\'HTTP_CLIENT_IP\'];
  } elseif (isset($_SERVER[\'HTTP_CF_CONNECTING_IP\']) && preg_match(\'/^([0-9]{1,3}\\.){3}[0-9]{1,3}$/\', $_SERVER[\'HTTP_CF_CONNECTING_IP\'])) {
    $ip = $_SERVER[\'HTTP_CF_CONNECTING_IP\'];
  } elseif (isset($_SERVER[\'HTTP_X_REAL_IP\']) && preg_match(\'/^([0-9]{1,3}\\.){3}[0-9]{1,3}$/\', $_SERVER[\'HTTP_X_REAL_IP\'])) {
    $ip = $_SERVER[\'HTTP_X_REAL_IP\'];
  }
  return $ip;
}