how to write backup script for website php code example

Example: how to do backup to website in php code

if (!file_exists('/home/sites/'.$_SERVER['SERVER_NAME'].'/cbitsbackup/')) {
mkdir('/home/sites/'.$_SERVER['SERVER_NAME'].'/cbitsbackup/', 0777, true);
}
$filefront = '/home/sites/'.$_SERVER['SERVER_NAME'].'/cbitsbackup/backup-'.$_SERVER['SERVER_NAME'].'-day1';
$fileend = '.zip';
$time = time();

if(file_exists($filefront.$fileend)){
$file = $filefront.'-'.$time.$fileend;}
else{$file = $filefront.$fileend;};
zip_directory('/home/sites/'.$_SERVER['SERVER_NAME'].'/public_html',$file);


function zip_directory($source,$tempfile){
if(!extension_loaded('zip') || !file_exists($source)) return false;
$zip = new ZipArchive();
if(!$zip->open($tempfile,ZIPARCHIVE::CREATE)) return false;
$source = str_replace('\\','/',realpath($source));
if(is_dir($source) === true){
    $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($source), RecursiveIteratorIterator::SELF_FIRST);
    foreach($files as $file){
        $file = str_replace('\\', '/', realpath($file));
        if(is_dir($file) === true) $zip->addEmptyDir(str_replace($source . '/','', $file . '/'));
        else if(is_file($file) === true) $zip->addFromString(str_replace($source . '/', '', $file), file_get_contents($file));}}
elseif(is_file($source) === true) $zip->addFromString(basename($source), file_get_contents($source));
return $zip->close();}