PHP: Download file from Server - php

Question

I have tried all sorts of codes I've found but nothing has worked for me...
When I use readfile() or fopen() or something like this:
function makeDownload($file, $dir, $type) {
header("Content-Type: $type");
header("Content-Disposition: attachment; filename=\"$file\"");
readfile($dir.$file);
}
... A download is started but the file is always empty...
here's the last code I've tried:
$filename = "gandalf.jpg";
// define error message
$err = '<p style="color:#990000">Sorry, the file you are requesting is unavailable.</p>';
if (!$filename) {
// if variable $filename is NULL or false display the message
echo " filename NULL";
echo $err;
} else {
// define the path to your download folder plus assign the file name
$path = 'upload/'.$filename;
// check that file exists and is readable
if (file_exists($path) && is_readable($path)) {
echo "file exists";
// get the file size and send the http headers
$size = filesize($path);
header('Content-Type: image/png');
header('Content-Length: '.$size);
header('Content-Disposition: attachment; filename='.$filename);
header('Content-Transfer-Encoding: binary');
// open the file in binary read-only mode
// display the error message if file can't be opened
//readfile($path.$filename);
$file = # fopen($path, 'rb');
if ($file) {
// stream the file and exit the script when complete
fpassthru($file);
exit;
} else {
echo $err;
}
} else {
echo $err;
}
}
This is the source of my code: Source code
I hope you can help me :)
I use google chrome
I need your help for this little project: Link to Project
When you click on a file in the drop down appears "herunterladen" (download in german) here is where I want to start the php download code
I just need the most basic download function for PHP... why is there an upload example on w3schools but NOT a download example? oO

Answer 1

$fileSource= $_GET['fileSource']; //If you are passing the filename as a URL parameter
$fileSource= "sample.pdf" //If the filename is fixed in the current folder
if($fileSource) {
$filesize = filesize($fileSource);
$path_parts = pathinfo($fileSource);
$ext = strtolower($path_parts["extension"]);
switch ($ext) {
case "pdf":
header("Content-Disposition: attachment;
filename=\"".$path_parts["basename"]."\""); // use 'attachment' to
force a download
header("Content-type: application/pdf"); // add here more headers
for diff. extensions
break;
default:
header("Content-type: application/octet-stream");
header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
}
if($filesize) {
header("Content-length: $filesize");
}
readfile($fileSource);
exit;
}