Download selected files into zip format in wordpress - php

Question

I am using a wordpress template page download.php and the code is :
$ck=$_REQUEST['select'];
$num=count($ck);
$zip_file_name='demodown.zip';
$zip = new ZipArchive();
if ($zip->open($zip_file_name, ZIPARCHIVE::CREATE )!==TRUE)
{
exit("cannot open <$zip_file_name>\n");
}
$file_path = $_SERVER['DOCUMENT_ROOT']."/lab4/brazil_resource/wp-content/pdf_upload/";
for($i=0;$i<$num;$i++)
{
$sql=mysql_query("select * from wp_pagecontent where id='$ck[$i]'");
$f=mysql_fetch_array($sql);
$files=$f['pdf_file'];
$zip->addFile($file_path.$files,$files);
}
$zip->close();
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="'.$zip_file_name.'"');
exit;
Using the above code I cannot zip the files that are selected. The download files in showing 0 bytes size.
Please help

Answer 1

I had solved it now finally
$zip_file_name='demo.zip';
$zip = new ZipArchive();
$tmp_file = tempnam('.','');
$zip->open($tmp_file, ZipArchive::CREATE);
$file_path = content_url()."/pdf_upload/";
foreach($_REQUEST['select'] as $file)
{
$download_file = $file_path.$file;
$download_file2 = file_get_contents($download_file);
$zip->addFromString('files/'.$file,$download_file2);
}
$zip->close();
if(file_exists($tmp_file))
{
// push to download the zip
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="'.$zip_file_name.'"');
readfile($tmp_file);
// remove zip file is exists in temp path
}

Answer 2

I have solved the other issue with the following code:
$zip_file_name='demo.zip';
$zip = new ZipArchive();
$tmp_file = tempnam('.','');
$zip->open($tmp_file, ZipArchive::CREATE);
for($i=0;$i<$num;$i++)
{
$sql=mysql_query("select * from wp_pagecontent where id='$ck[$i]'");
$f=mysql_fetch_array($sql);
$files=$f['pdf_file'];
$download_file = file_get_contents($files);
//$fe=$file_path.$files;
//$zip->addFromString(basename($fe),file_get_contents($fe));
$zip->addFromString(basename($files),$download_file);
}
$zip->close();
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="'.$zip_file_name.'"');
header("Content-length: ".filesize($zip_file_name));
readfile($tmp_file);
exit;