$file_name = $_GET['file'];

// make sure it's a file before doing anything!
if(is_file($file_name))
{

/*
Do any processing you'd like here:
1.  Increment a counter
2.  Do something with the DB
3.  Check user permissions
4.  Anything you want!
*/

// required for IE
if(ini_get('zlib.output_compression')) { ini_set('zlib.output_compression', 'Off'); }

// get the file mime type using the file extension
switch(strtolower(substr(strrchr($file_name,'.'),1)))
{
case 'pdf': $mime = 'application/pdf'; break;
case 'zip': $mime = 'application/zip'; break;
case 'jpeg':
case 'jpg': $mime = 'image/jpg'; break;
default: $mime = 'application/force-download';
}
header('Pragma: public');   // required
header('Expires: 0');       // no cache
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private',false);
header('Content-Type: '.$mime);
header('Content-Disposition: attachment; filename="'.basename($file_name).'"');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.filesize($file_name));    // provide file size
readfile($file_name);       // push it out
exit();

}