setting up filepath

[Lassie]

I am trying to build a download that needs to establish a filepath.
There is a download dir which holds a hash folder, which holds the files.
I can get as far as indentifying the files but I cant seem to attach the file name to the dir/hash path.
How can i capture the file name?

[code]
//open the dir
$folder= opendir("C:pick_up/$hash");
//check if dir opened -  to be done
// prepare the download
//loop through the directory
while($file = readdir($folder))
{
if($file !='.'&& $file != '..') echo "$file<br>";
}
closedir($folder);


$filepath = 'C:/pick_up/$hash/'.$file;//doen't attach file name and ext
echo"$filepath";
// check that it exists and is readable
if (file_exists($filepath) && is_readable($filepath))
{

// get the file's size and send the appropriate headers

$size = filesize($filepath);
header('Content-Type: application/octet-stream');
header('Content-Length: '.$size);
header('Content-Disposition: attachment; filename='.$file);
header('Content-Transfer-Encoding: binary');
// open the file in binary read-only mode

$file = fopen($filepath, 'rb');
if ($file) {
// stream the file and exit the script when complete
fpassthru($file);

exit;
}
else {
echo "$nogo";
  }
}
[/code]