php 强制下载文件实现代码

<?php
$file = monkey.gif;

if (file_exists($file)) {
    header(Content-Description: File Transfer);
    header(Content-Type: application/octet-stream);
    header(Content-Disposition: attachment; filename=.basename($file));
    header(Content-Transfer-Encoding: binary);
    header(Expires: 0);
    header(Cache-Control: must-revalidate, post-check=0, pre-check=0);
    header(Pragma: public);
    header(Content-Length: . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exit;
}
?>
?
<?php
header("Content-Type: application/force-download");
header("Content-Disposition: attachment; filename=ins.jpg"); 
readfile("imgs/test_Zoom.jpg");
?>