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Create Zip file in PHP, Force Download allowing Download Managers

Posted on 2008-10-14
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Last Modified: 2013-12-25
Hi,

I'm looking to create a zip file on the fly and download it immediately using PHP. The purpose is to allow users to select a number of files on our server and download them in a tidy zip. I'm having problems with IE7 and Getright however.

Basically, I want to create a unique filename for the zip, store it on the server and force the user to download it. Ideally then I will also delete the file to prevent the server clogging up. Firefox is fine with this code however if you combine a download manager, it creates two (sometimes three!) unique files. I can only assume that the sessions do not transfer to the download manager so it creates a new file.

I've attached some code as shown below where I've tried to use sessions to get around the problem.

(I'm using the pear/zip files from another project - there may be a better way?)


<?
	session_start();
	include ('pear/Zip.php');
 
	// For testing only (we have database queries etc here)
	$filearray = array("file1.jpg,file2.jpg,file3.jpg"); 
 
	if (isset($_SESSION['dl_filename'])) {
		$zipname = $_SESSION['dl_filename'];
	} else {
		$zipname = "masszip_".rand(0,99999).".zip";
		session_register('dl_filename');
		$_SESSION['dl_filename'] = $zipname;
		$zipfile = New Archive_Zip($zipname);
		$zipfile->create($filearray);	
	}
 
 
	header("Content-Type: application/zip ");
	header("Content-Disposition: attachment; filename=".$zipname);
	readfile($zipname); 
?>

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Question by:djdiablo
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3 Comments
 
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Accepted Solution

by:
hampus_b earned 100 total points
ID: 22710262
why not create a not so unique zip? for example, concat the names of the files and make a hash from the names. then the request for the same files would ask for the same file, and you could leave it on the server.

Or, with mod rewrite in apache, point *.zip files to a php-script, and let php create the zip on the fly like this:
site.com/files/a.doc_b.doc_c.doc.zip

The script can then serve the files on the fly or cache them on the server.
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LVL 1

Author Closing Comment

by:djdiablo
ID: 31505831
Thanks, a good common sense answer which I hadn't thought of!
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Author Comment

by:djdiablo
ID: 22713686
Using the above solution, I created the following code. It now works as required without the need for sessions. Thanks for your help!
	// Create MD5
	$md5files = md5(implode("",$filearray));
	$md5n = strtolower(substr($md5files,0,7));
	
	// Add to Filename
	$zipname = "masszip_".$md5n.".zip";
	
	if (file_exists($zipname)) {
		$already = 1;
	} else {
		$zipfile = New Archive_Zip($zipname);
		$zipfile->create($filearray);	
	}
 
	header("Content-Type: application/zip ");
	header("Content-Disposition: attachment; filename=".$zipname);
	header("Content-Length: ".filesize($zipname));
	readfile("$zipname"); 

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