PHP Zip Class

A better PHP zipping/unzipping class.

The problem

When building a CMS that is supposed to be redistributable and functioning on a range of hosting solutions (shared, VPS, dedicated) a problem often occurs in zipping and unzipping files. since not all PHP installation have the zipArchive class exists.

Case: Duplicator plugin for WordPress

For a number of clients, a problem seemed often occurring due to missing zipArchive class:

• VPS
• VPS again
• Shared dreamhost
• Shared X10 Hosting
• Shared dreamhost
• cPanel
• Yet another case

However, although the plugin itself is was distributed as a zip file, the WordPress code was able to unzip and install it. This is because the WordPress core code will check if the zipArchive class exists, and if it does not, it will use the PclZip class which can be included as a PHP file and considered as an alternative for zipArchive.

The solution

In this class, I tried to solve this problem in the same approach that the WordPress core team did; by checking if the class zipArchive exists or not, and using PclZip if it does not.

This does NOT solve missing the zlib extension which is a requirement even for the PclZip class. However, missing the zlib extension is less common than just missing the zipArchive class.

This class also provides a very simple and intuitive way of dealing with zip files.

Installation

To install this class, simply upload the src folder contents to your server and include the Zip.php file.

Note: To install in CodeIgniter create a folder called zip in your in application/libraries/ and put the src folder contents inside of it, then load it using the library loader $this->load->library("zip/zip");.

Usage Examples:

Note: When I wrote this class, I intended to use it in a multi-line fashion (You'll see what I mean). However, I decided later that I should make a shorthand for this, so it would be usable in a one-line style.

Adding new files to the zip / Creating new zip file:

Multi-line style

• PHP:

    require_once "path/to/src/zip.php";
    $zip = new Zip();
    $zip->zip_start("path/to/new/or/old/zip_file.zip");
    $zip->zip_add("path/to/example.png"); // adding a file
    $zip->zip_add(array("path/to/example1.png","path/to/example2.png")); // adding two files as an array
    $zip->zip_add(array("path/to/example1.png","path/to/directory/")); // adding one file and one directory
    $zip->zip_end();

• CodeIgniter:

	$this->load->library("zip/zip");
    $this->zip->zip_start("path/to/new/or/old/zip_file.zip");
    $this->zip->zip_add("path/to/example.png"); // adding a file
    $this->zip->zip_add(array("path/to/example1.png","path/to/example2.png")); // adding two files as an array
    $this->zip->zip_add(array("path/to/example1.png","path/to/directory/")); // adding one file and one directory
    $this->zip->zip_end();

one-line style

• PHP:

    require_once "path/to/src/zip.php";
    $zip = new Zip();
    $zip->zip_files(array("path/to/new/or/old/zip_file.zip","path/to/directory/"),"path/to/zip/file.zip");

• CodeIgniter:

	$this->load->library("zip/zip");
    $this->zip->zip_files(array("path/to/new/or/old/zip_file.zip","path/to/directory/"),"path/to/zip/file.zip");

Extracting (unzipping) files:

Multi-line style

• PHP:

    require_once "path/to/src/zip.php";
    $zip = new Zip();
    $zip->unzip_file("path/to/new/or/old/zip_file.zip");
    $zip->unzip_to("path/to/containing/directory/");

• CodeIgniter:

	$this->load->library("zip/zip");
    $this->zip->unzip_file("path/to/new/or/old/zip_file.zip");
    $this->zip->unzip_to("path/to/containing/directory/");

one-line style

• PHP:

    require_once "path/to/src/zip.php";
    $zip = new Zip();
    $zip->unzip_file("path/to/new/or/old/zip_file.zip","path/to/containing/directory/");

• CodeIgniter:

	$this->load->library("zip/zip");
    $this->zip->unzip_file("path/to/new/or/old/zip_file.zip","path/to/containing/directory/");

Note: The library will throw a new exception in case of error and will return true in case of success.

Testing

    cd test && php test.php

Credits

• This approach of solution was inspired by WordPress.
• PHPConcept for creating PclZip, an awesome alternative for zipArchive.