<?php

$zipFile = "tmp/data.zip";

//prepare the archive to be unpacked
if (!is_dir("tmp")) {
    mkdir("tmp");
}
$source = new ZipArchive();
$source->open($zipFile,
    ZipArchive::CREATE | ZipArchive::OVERWRITE);
$source->addFromString("file.txt", "Hello, world!\n");
$source->close();

$zip = new ZipArchive;
$res = $zip->open($zipFile);
if ($res === TRUE) {
    $zip->extractTo('tmp/');
    $zip->close();
} else {
    throw new Exception("Could not open archive");
}