How to Zip and Unzip Files in PHP

Network transfer file compression has significant advantages. The total file size after compression is usually greatly reduced, saving bandwidth and speeding up user downloads. Users can decompress at any time after downloading. In short, compression can significantly simplify network transfers of files for you and your visitors.

Manually compressing files can be cumbersome, but luckily, PHP offers many extensions that specialize in handling file compression and decompression. You can use the functions in these extensions to automatically compress PHP files.

This tutorial will guide you how to compress files into zip archives in PHP and decompress files from zip archives. You will also learn how to delete or rename files in your archive without decompressing first.

PHP Single File Compression
Multiple File Compression in Directory
Modify or Overwrite Archive
Extract Content from Archive
More Archive Control

PHP Single File Compression

PHP's

ZipArchive::RDONLY>The PHP's

ZipArchive::RDONLY

>The logo of PHP (available in PHP 7.4.3 and later) allows you to open the archive in read-only mode.

You can consult the documentation for this method to understand the different error codes returned when opening a file fails. If the zip file is successfully opened or created, the method returns the ZipArchive::OVERWRITE flag if the content of an existing archive does not matter. If an archive with that specific name does not exist, it does not create a new archive.

$zip->open('my_compressed_files.zip', ZipArchive::OVERWRITE|ZipArchive::CREATE);

You can use ZipArchive::CREATE in combination to overwrite an existing archive and create a new archive if there is no archive with that specific name. Examples are as follows:

Use the ZipArchive::CREATE and open() methods to open a new or existing archive for read and write.

In this section, we will understand the differences that may arise due to different combinations of flags passed to $options, passing to ZipArchive::CREATE will create a new archive or modify an existing archive if it already exists. You will not receive any warnings about modifying existing archives. This means that if you execute the code in this section to create the archive and then execute it again after replacing the original option with the new option, you will get some unexpected results. The archive will then contain a wallpapers directory containing the subdirectories files/images and images from the

wallpapers

directory. It can be a little confusing at first and may make you wonder why if you want to overwrite everything in the archive (if it already exists), but if you don't want the code to throw an error if it doesn't exist, then use ZipArchive::CREATE|ZipArchive::OVERWRITE.

Also remember that since libzip 1.6.0, empty files are no longer considered valid archives.

Extract content from archiveZipArchive extractTo($destination, $entries)$entries The class has a method called

to extract the archived content. You can use it to extract everything in the archive or just extract some specific files. The parameter can be used to specify the single file name to be extracted, or to pass a file array.

One thing to remember is that you need to specify the correct path to the file in the archive to extract it. For example, we archived a font file named AlegreyaSans-Light.ttf in the previous section. This file is stored in a directory named font_files in the archive. This means that the path you need to specify in the $entries parameter is font_files/AlegreyaSans-Light.ttf, not just AlegreyaSans-Light.ttf.

Directory and file structure will be retained during the extraction process, and the files will be extracted to their respective directories.

$zip->open('my_compressed_files.zip', ZipArchive::OVERWRITE|ZipArchive::CREATE);

If the second parameter is omitted, the method will extract all files in the archive.

More Archive Controls

The

ZipArchive class also provides many other methods and properties to help you get more information about the archive before extracting everything.

You can use the count() method to calculate the number of files in the archive. Another option is to use the numFiles attribute. They can be used to iterate over all files in the archive, extract only the required files, or you can do other actions on them, such as removing them from the archive.

In the following example, we are deleting all files in the archive that contain the word Italic. Similar codes can be used to delete all files that do not contain specific words. You can also iterate over these files and replace specific words with other content.

<?php

$zip = new ZipArchive();
$zip->open('compressed/user_archive.zip', ZipArchive::CREATE);
$zip->extractTo('uncompressed/', 'font_files/AlegreyaSans-Light.ttf');
$zip->close();

?>

In the above code, we use deleteName() to delete a single file. However, you can also use it to delete the entire directory.

Similar functions renameName($oldname, $newname) can be used to change the name of any file in the archive. If a file named $newname already exists, you will receive an error message.

Summary

We introduced many very useful methods of the ZipArchive class that will make automatic compression and decompression of files in PHP a breeze. You should now be able to compress a single file or a group of files at once based on your own standards. Again, you should be able to extract any specific file from the archive without affecting other content.

With the help of count() and numFiles, you can have better control over individual files, and renaming or deleting them will be very easy. You should read the documentation at least once to learn more about such functions.

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