Create ZIP Archive for Download

PHP Tutorials - Herong's Tutorial Examples

∟Create ZIP Archive for Download

This section provides a tutorial example on how to create a ZIP archive in a temporary file with dymanic data and send it to Web browser as a download using the ZipArchive class.

If you have data items from database for Users to download from a Web server, you may want to ZIP them on the fly so users can download them in a single ZIP file.

Of course, the best option is to retrieve data items from database in memory, ZIP them in memory and send the ZIP to user's browser without creating any physical files on the Web server. However, this is not doable with the ZipArchive class, which does not support ZIP archive as file handles or pipes.

The next option is to retrieve data items from database in memory, ZIP them in a temporary file and remove it after sending it to user's browser. This can be done the following steps:

1. Create a unique file name in the system temporary directory as the ZIP file name:

$tmpDir = sys_get_temp_dir();
$zipFile = tempnam($tmpDir, "ZIP"); # ZIP is the prefix for temp name

2. Open the temporary file and the ZIP archive:

$zip->open($zipFile, ZipArchive::CREATE);

3. Retrieve data items from database and loop over each item.

4. Create an unique name for each item, and the item data to the ZIP archive as a string.

$itemData = ...; # based data from database
$itemName = ...; # based record ID from database
$zip->addFromString("$itemName", $itemData);

5. Close the ZIP archive, read the ZIP data back from the temporary file, and remove it immediately.

$zip->close();
$zipData = file_get_contents($zipFile);
unlink($zipFile);

6. Send the ZIP data to the Web browser.

Here is an example script that creates a new ZIP archive in temporary file with dynamic data items. The ZIP archive is then pushed to client browser.

<?php
#  zip-in-temp-file.php
#- Copyright 2009 (c) HerongYang.com. All Rights Reserved.
  $dir = "msg";
  $file = 'hello.txt';

  $tmpDir = sys_get_temp_dir();
  $zipFile = tempnam($tmpDir, "ZIP");

  $zip = new ZipArchive;
  error_log("Creating ZIP file $zipFile");
  $rc = $zip->open($zipFile, ZipArchive::CREATE);
  if ($rc === TRUE) {
    if ($zip->addEmptyDir($dir) === TRUE) error_log("$dir added");

    # this could be any data and muliple times
    if ($zip->addFromString("$dir/$file", 'Hello world!') === TRUE)
      error_log("$file added");

    $zip->close();
  } else {
    error_log("Failed to create ZIP with error: $rc");
  }

  $zipData = file_get_contents($zipFile);
  unlink($zipFile);

  header("Content-Type: application/octet-stream");
  header("Content-Disposition: attachment; filename=Hello.zip");
  header("Content-Length: " . strlen($zipData));
  header("Cache-Control: no-cache");
  print($zipData);
?>