How to support IDM without allow request the page two times

Question

I got this error ,as the above image show, while trying to download a file by IDM from my site. the limit of requesting this page one time only after entering Captcha Code and if you request the page again must enter the captcha code again.

How to support IDM in this case

The download code as the following

$file='test.mp3';
$download_rate = 50; //50 kb/s

if(file_exists($file) && is_file($file))
{
    header('Cache-control: private');
    header('Content-Type: application/octet-stream');
    header('Content-Length: '.filesize($file));
    header('Content-Disposition: filename='.$file);

    flush();
    $file = fopen($file, "r");

    while(!feof($file))
    {
        // send the current file part to the browser
        print fread($file, round($download_rate * 1024));
        // flush the content to the browser
        flush();
        // sleep one second
        sleep(1);
    }
    fclose($file);
    }
else {
    echo 'File Not Found';
}

Answer 1

Use xsendfile. A mod for apache

https://tn123.org/mod_xsendfile/