获取远程图片的体积大小

//用法 echo remote_filesize($url,$user='',$pw='');
$url = "http://www.nowamagic.net/librarys/images/random/rand_11.jpg";
echo remote_filesize($url,$user='',$pw='');

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); //

启用时会将头文件的信息作为数据流输出

curl_setopt($ch, CURLOPT_NOBODY, 1); // if auth is needed, do it hereif (!empty($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$head = ob_get_contents(); // clean the output buffer and return to previous // buffer settingsob_end_clean(); // gets you the numeric value from the Content-Length // field in the http header$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';}$last_mb = round($size/(1024*1024),3);$last_kb = round($size/1024,3);return $last_kb . 'KB / ' . $last_mb.' MB';}

函数的思路是，先CURL获取图片到缓冲区，然后正则获取图片的Content-Length信息就OK了。