PHP标头强制下载-不起作用

Question

Hi I have this code but not happens, any idea? When I run this page, I got a blank page, one thing that I don't understand is the filename is just the name and no the entire address. A url is like this, with the complete address:

http://site.com/download_orig.php?file=prod_media/images/neografik_pty_ltd/product_test_10/192027102011_istock_000016116673xsmall.jpg

Cheers, M

<?php

$filename = $_GET['file'];
if (!is_file($filename)) {
    header('Location: home.php'); exit;
}
$filepath = str_replace('\\', '/', realpath($filename));
$filesize = filesize($filepath);
$filename = substr(strrchr('/'.$filepath, '/'), 1);
$extension = strtolower(substr(strrchr($filepath, '.'), 1));
switch($extension) {
    case "pdf": $mime="application/pdf"; break;
    case "rvt": $mime="application/octet-stream"; break;
    case "rft": $mime="application/octet-stream"; break;
    case "rfa": $mime="application/octet-stream"; break;
    case "xls": $mime="application/vnd.ms-excel"; break;
    case "xlsx": $mime="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; break;  
    case "dwg": $mime="application/acad"; break;
    case "dwf": $mime="application/acad"; break;
    case "gif": $mime="image/gif"; break;
    case "png": $mime="image/png"; break;
    case "jpeg":
    case "jpg": $mime="image/jpg"; break;
    default: $mime=0;
}

// use this unless you want to find the mime type based on extension
// $mime = array('application/octet-stream');

// Only allowed files here, no hack and stuff, sorry
if($mime===0) header('Location: home.php'); exit;

header('Content-Description: File Transfer');
header('Content-Type: '.$mime);
header('Content-Disposition: attachment; filename='.basename($filename));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Content-Length: '.sprintf('%d', $filesize));

// check for IE only headers
if (isset($_SERVER['HTTP_USER_AGENT']) && (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false)) {
  header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
  header('Pragma: public');
} else {
  header('Pragma: no-cache');
}
ob_clean();
flush();
readfile($filename);
exit;
?>

Answer 1

You have

if($mime===0) header('Location: home.php'); exit;

exit is always called (even if $mime is not zero) causing program to terminate. Do this:

if($mime===0) { header('Location: home.php'); exit; }