php获取远程图片体积大小的实例

　　//用法 echo remote_filesize($url,$user='',$pw='');

　　$url = "http://www.aa.com/librarys/images/random/rand_11.jpg";//这里要换成你的图片地址

　　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); // 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';

　　}

　　$last_mb = round($size/(1024*1024),3);

　　$last_kb = round($size/1024,3);

　　return $last_kb . 'KB / ' . $last_mb.' MB';

　　}