PHP 获取远程文件的大小的3种方法

1、使用file_get_contents()

<?php
$file = file_get_contents($url);
echo strlen($file);
?>

2. 使用get_headers()

<?php
$header_array = get_headers($url, true);
$size = $header_array['Content-Length'];
echo $size;
?>

PS:

需要打开allow_url_fopen!
如未打开会显示
Warning: get_headers() [function.get-headers]: URL file-access is disabled in the server configuration

3.使用fsockopen()

<?php
function get_file_size($url) {
$url = parse_url($url);

if (empty($url['host'])) {
return false;
}

$url['port'] = empty($url['post']) ? 80 : $url['post'];
$url['path'] = empty($url['path']) ? '/' : $url['path'];

$fp = fsockopen($url['host'], $url['port'], $error);

if($fp) {
fputs($fp, "GET " . $url['path'] . " HTTP/1.1\r\n");
fputs($fp, "Host:" . $url['host']. "\r\n\r\n");

while (!feof($fp)) {
$str = fgets($fp);
if (trim($str) == '') {
break;
}elseif(preg_match('/Content-Length:(.*)/si', $str, $arr)) {
return trim($arr[1]);
}
}
fclose ( $fp);
return false;
}else {
return false;
}
}

?>