php 获取301 302的真实地址

function getRealURL($url){

     $header = get_headers($url,1);

     if (strpos($header[0],'301') || strpos($header[0],'302')) {

         if(is_array($header['Location'])) {

             return $header['Location'][count($header['Location'])-1];

         }else{

             return $header['Location'];

         }

     }else {

         return $url;

     }

 }