Wordpress Backup With Client Request

backup.php

<?php

ini_set('max_execution_time', 0);
error_reporting(E_ALL);
ini_set('display_errors','On');

$rootPath = realpath(__DIR__);

$zip = new ZipArchive();
$zip->open('backup_'.uniqid().'.zip', ZipArchive::CREATE | ZipArchive::OVERWRITE);

$files = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator($rootPath),
    RecursiveIteratorIterator::LEAVES_ONLY
);

foreach ($files as $name => $file)
{
    if( ! in_array($file->getFilename(), ['.', '..']) ){

        // Skip directories (they would be added automatically)
        if ( ! $file->isDir() )
        {
            $filePath = $file->getRealPath();
            $relativePath = substr($filePath, strlen($rootPath) + 1);
            $zip->addFile($filePath, $relativePath);
        }

    }
}

$zip->close();