用于从服务器下载pdf文件的PHP代码无效

Question

I have written a code to download pdf file from server, but the code is not working and I cant even see the errors This is the code which I am using.

// place this code inside a php file and call it f.e. "download.php"
$path = $_SERVER['DOCUMENT_ROOT']."/product_images/"; // change the path to fit your     websites document structure
fullPath = $path.$_REQUEST['download_file'];

if ($fd = fopen ($fullPath, "r")) {
$fsize = filesize($fullPath);
$path_parts = pathinfo($fullPath);
$ext = strtolower($path_parts["extension"]);
switch ($ext) {
    case "pdf":
    header("Content-type: application/pdf"); // add here more headers for diff.     extensions
    header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\"");     // use 'attachment' to force a download
    break;
    default;
    header("Content-type: application/octet-stream");
    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
}
header("Content-length: $fsize");
header("Cache-control: private"); //use this to open files directly
while(!feof($fd)) {
    $buffer = fread($fd, 2048);
    echo $buffer;
}
}
fclose ($fd);
exit;
// example: place this kind of link into the document where the file download is offered:
// <a href="download.php?download_file=some_file.pdf">Download here</a>
?>

I am fetching the file from database and this is my download link which I am using on my site

<div style="padding-left:320px; padding-top:5px;"><a href="<?php echo URL ?>download.php?download_file=<?php echo $prod_details['specification_pdf']?>">
<img src="<?php       echo URL ?>images/download_pdf.png" /></a></div>
</div>

Can anyone please help me in resolving this problem

Answer 1

As say @lasar missing $ in line 2 could be the problem. I adapt (and test) your code to be more secure (see basename) and direct (see readfile):

<?php
$path = $_SERVER['DOCUMENT_ROOT']."/product_images/"; // change the path to fit your     websites document structure
$fullPath = $path.basename($_REQUEST['download_file']);

if (is_readable ($fullPath)) {
$fsize = filesize($fullPath);
$path_parts = pathinfo($fullPath);
$ext = strtolower($path_parts["extension"]);
switch ($ext) {
    case "pdf":
    header("Content-type: application/pdf"); // add here more headers for diff.     extensions
    header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\"");     // use 'attachment' to force a download
    break;
    default;
    header("Content-type: application/octet-stream");
    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
}
header("Content-length: $fsize");
header("Cache-control: private"); //use this to open files directly
readfile($fullPath);
exit;
} else {
        die("Invalid request");
}
// example: place this kind of link into the document where the file download is offered:
// <a href="download.php?download_file=some_file.pdf">Download here</a>

ADD

• see readfile manual page for a good explanation of headers to download files
• REMEMBER due it's nature PHP is well know to damage binary file download, remeber to keep <?php always in 1st line and avoid close tag ?> in PHP-only files