php获取客户端ip地址方法

 /**
      * 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   $adv 是否进行高级模式获取（有可能被伪装）
      * @return mixed
      */
     public function ip($type = 0, $adv = true)
     {
         $type      = $type ? 1 : 0;
         static $ip = null;
         if (null !== $ip) {
             return $ip[$type];
         }

         $httpAgentIp = Config::get('http_agent_ip');

         if ($httpAgentIp && isset($_SERVER[$httpAgentIp])) {
             $ip = $_SERVER[$httpAgentIp];
         } elseif ($adv) {
             if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
                 $arr = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
                 $pos = array_search('unknown', $arr);
                 if (false !== $pos) {
                     unset($arr[$pos]);
                 }
                 $ip = trim(current($arr));
             } 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   = $long ? [$ip, $long] : ['0.0.0.0', 0];
         return $ip[$type];
     }