PHP将微博短地址还原为实际网址方法

<?php
$url= " http://163.fm/1QLJ8U";
echounshorten($url);
functionunshorten($url)
{
    $url= trim($url);
    $headers= get_headers($url);
    $location= $url;
    $short= false;
    foreach($headersas$head)
    {
        if($head=="HTTP/1.1 302 Found")
            $short= true;
        if($short&& startwith($head,"Location: "))
        {
            $location= substr($head,10);
        }
    }
    return$location;
}
functionstartwith($Haystack, $Needle)
{
    returnstrpos($Haystack, $Needle) === 0;
}
?>