php常用代码片段

1,获取用户真实ip
/**

• 获取客户端IP地址
• @param integer $type 返回类型 0 返回IP地址 1 返回IPV4地址数字
• @param boolean $adv 是否进行高级模式获取（有可能被伪装）
• @return mixed
  */
  public function get_client_ip( $type = 0, $adv = true ) {
  $type = $type ? 1 : 0;
  static $ip = NULL;
  if ($ip !== NULL) return $ip[$type];
  if($adv){
  if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
  $arr = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
  $pos = array_search('unknown',$arr);
  if(false !== $pos) unset($arr[$pos]);
  $ip = trim($arr[0]);
  }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
  $ip = $_SERVER['HTTP_CLIENT_IP'];
  }elseif (isset($_SERVER['REMOTE_ADDR'])) {
  $ip = $_SERVER['REMOTE_ADDR'];
  }
  }elseif (isset($_SERVER['REMOTE_ADDR'])) {
  $ip = $_SERVER['REMOTE_ADDR'];
  }
  // IP地址合法验证
  $long = sprintf("%u",ip2long($ip));
  $ip = $long ? array($ip, $long) : array('0.0.0.0', 0);
  return $ip[$type];
  }