php短域名转换为实际域名函数

$url="http://sinaurl.cn/hbdsU5";
echounshorten($url);
functionunshorten($url){
$url=trim($url);
$headers=get_headers($url);
$location=$url;
$short=false;
foreach($headersas$head){
if($head=="HTTP/1.1302Found")$short=true;
if($short&&startwith($head,"Location:")){
$location=substr($head,10);
}
}
return$location;
}
functionstartwith($Haystack,$Needle){
returnstrpos($Haystack,$Needle)===0;
}