What’s the best way to supply download of a digital product in PHP?

Digital commercial products that customers pay for download link.

I have put all the zipped files (products) outside of web document root and buyers download them via a php script which is integrated with paypal IPN to make sure the downloader is a paying buyer.

Sort of like: http://www.mysite.com/download.php?buyer_id=xxx

Thus far it all works with only one problem. The zip files I download via the URL above is corrupted and can't be opened correctly with WinRAR. However, directly downloaded zip is fine.

My code:

                $path = WAREHOUSE_PATH.'/products/'.$identifier.'.zip';
                        $mm_type="application/octet-stream";
                        header("Pragma: public");
                        header("Expires: 0");
                        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
                        header("Cache-Control: public");
                        header("Content-Description: File Transfer");
                        header("Content-Type: " . $mm_type);
                        header("Content-Length: " .(string)(filesize($path)) );
                        header('Content-Disposition: attachment; filename="'.basename($path).'"');
                        header("Content-Transfer-Encoding: binary\n");

                        $fp = @fopen($path,"rb");
                        if ($fp) {
                          while(!feof($fp)) {
                            print(fread($fp, 1024*8));
                            flush();
                            if (connection_status()!=0) {
                              @fclose($fp);
                              die();
                            }
                          }
                          @fclose($fp);
                        }

PHP:

What could be wrong? Thanks!

 

This looks odd to me ...

header('Content-Disposition: attachment; filename="'.basename($path).'"');

I have a similar download which has this ...

header('Content-Disposition: attachment; filename=' . basename($path));

And instead of:

$fp = @fopen($path,"rb"); if ($fp) { while(!feof($fp)) { print(fread($fp, 1024*8)); flush(); if (connection_status()!=0) { @fclose($fp); die(); } } @fclose($fp); }

Try

@readfile($path);

 

Thanks! problem solved. Seems I had a few unwanted white spaces before the download. Silly.