function remote_filesize($uri,$user='',$pw=''){
// start output buffering
ob_start();
// initialize curl with given uri
$ch = curl_init($uri); // make sure we get the header
curl_setopt($ch, CURLOPT_HEADER, 1); // make it a http HEAD request
curl_setopt($ch, CURLOPT_NOBODY, 1); // if auth is needed, do it here
if (!empty($user) && !empty($pw)) {
$headers = array('Authorization: Basic ' . base64_encode($user.':'.$pw));
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers); }
$okay = curl_exec($ch);
curl_close($ch); // get the output buffer
$head = ob_get_contents(); // clean the output buffer and return to previous // buffer settings
ob_end_clean(); // gets you the numeric value from the Content-Length // field in the http header
$regex = '/Content-Length:\s([0-9].+?)\s/';
$count = preg_match($regex, $head, $matches); // if there was a Content-Length field, its value // will now be in $matches[1]
if (isset($matches[1]))
{ $size = $matches[1]; }
else { $size = 'unknown'; }
$last=round($size/(1024*1024),3);
return $last.' MB';
}
//用法 echo remote_filesize($url,$user='',$pw='');