File download from server using mysql and PHP - php

Question

I have created a PHP page that allows users to download a file when they click the this link:
Download File
I have also created the download page that the link directs to:
<?php
if(isset($_GET['file'])) {
$fileID = $_GET['pubid'];
$filename= ($_GET['file']);
$path = "admin/pubfiles/";
$fullPath = $path . $filename;
mysql_select_db($database_connDioceseofife, $connDioceseofife);
$sql = "SELECT file FROM publications WHERE pubID = $fileID";
$result = mysql_query($sql) or die(mysql_error());
$row = mysql_fetch_assoc($result);
if($filename == NULL) {
die('No file exists or the name is invalid!');
}
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header("Content-Disposition: attachment; filename=\"$filename\"");
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
readfile($fullPath);
}
?>
Now my problem is, when the download popup window come up, it reads that the file is of 0 bytes. And when downloaded, it can't open. i get the message that it is not a supported file type or its been damaged or corrupted.
Please any help would be much appreciated.

Answer 1

You're not doing anything with the query result in $row.
Use $row['file'] to get the actual file itself.

Answer 2

Thank you all for assisting me. I have been able to solve the problem after further reading. I have updated the initial script i wrote. what is above is now the working script.
What i did was to include $fullpath = $path . $filename then changed the header("Content-Disposition: attachment; filename=\"$filename\""); and then the readfile function from readfile($path) to readfile($fullpath).
Thanks again #nlsbshtr and everybody else for your help.