ZIP all files in directory and download generated .zip

<?php
$dir = 'path/to/your/directory';
// Normalize directory path to prevent trailing slash issues
$dir = rtrim($dir, '/\\');

if (!is_dir($dir)) {
    die('Directory not found.');
}

// Initialize archive object
$zip = new ZipArchive();
$zip_name = time() . ".zip"; // Zip name
if ($zip->open($zip_name, ZipArchive::CREATE) !== true) {
    die('Failed to create zip file.');
}

// Create recursive directory iterator
/** @var SplFileInfo[] $files */
$files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($dir), RecursiveIteratorIterator::LEAVES_ONLY);

foreach ($files as $name => $file) {
  // Skip directories (they would be added automatically)
  if (!$file->isDir()) {
    // Get real and relative path for current file
    $filePath = $file->getRealPath();
    $relativePath = substr($filePath, strlen($dir) + 1);

    // Add current file to archive
    $zip->addFile($filePath, $relativePath);
  }
}

// Zip archive will be created only after closing object
$zip->close();

//then prompt user to download the zip file
header('Content-Type: application/zip');
header('Content-Disposition: attachment; filename=' . $zip_name);
header('Content-Length: ' . filesize($zip_name));
readfile($zip_name);

//cleanup the zip file
unlink($zip_name);
exit;
?>