PHP如何通过URL访问，获得新的URL 两种方法

1.1

 $url = 'http://passport.drcloud.cn/api/logon.asp?id=1&ru=http://203.158.158.122/store/thirdLogin.php&tw=1800&sm=0&lc=2052';
 $newurl = getMapUrl($url);
 echo $newurl;

 function getMapUrl($url){
     $result = get_headers($url, true);
     return isset($result['Location'])? $result['Location'] : '';
 }

1.2

 $url = 'http://passport.drcloud.cn/api/logon.asp?id=1&ru=http://203.158.158.122/store/thirdLogin.php&tw=1800&sm=0&lc=2052';
 $newurl = getMapUrl($url);
 echo $newurl;

 function getMapUrl($url){
     file_get_contents($url);
     $result = $http_response_header;
     if($result){
         foreach($result as $val){
             if(substr($val,0,10)=='Location: '){
                 return str_replace('Location: ','', $val);
             }
         }
     }
     return '';
 }

2

 $url = 'http://passport.drcloud.cn/api/logon.asp?id=1&ru=http://203.158.158.122/store/thirdLogin.php&tw=1800&sm=0&lc=2052';
 $newurl = getHeadersNew($url);
 var_dump($newurl);
 function getHeadersNew($url){
     $ch= curl_init();
     curl_setopt($ch, CURLOPT_URL, $url);
     curl_setopt($ch, CURLOPT_NOBODY, 1);
     curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
     curl_setopt($ch, CURLOPT_HEADER, 1);
     $f=curl_exec($ch);
     curl_close($ch);
     $h=explode("\n",$f);
     $r=array();
     foreach( $h as $t){
       $rr=explode(":",$t,2);
       if(count($rr)==2 ){ $r[$rr[0]]=trim($rr[1]);}
     }
     return $r;
 }