/**
* 文件下载
* @param $filepath 文件路径
* @param $filename 文件名称
*/
function file_down($filepath, $filename = '') {
if(!$filename) $filename = basename($filepath);
if(is_ie()) $filename = rawurlencode($filename);
$filetype = fileext($filename);
$filesize = sprintf("%u", filesize($filepath));
if(ob_get_length() !== false) @ob_end_clean();
header('Pragma: public');
header('Last-Modified: '.gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: pre-check=0, post-check=0, max-age=0');
header('Content-Transfer-Encoding: binary');
header('Content-Encoding: none');
header('Content-type: '.$filetype);
header('Content-Disposition: attachment; filename="'.$filename.'"');
header('Content-length: '.$filesize);
readfile($filepath);
exit;
}
