Super simple class to encode an object into XML.

simple_xml_encode.php

<?php
class XML {
    /**
     * Encode an object as XML string
     *
     * @param Object $obj
     * @param string $root_node
     * @return string $xml
     */
    public static function encodeObj($obj, $root_node = 'response') {
        $xml = '<?xml version="1.0" encoding="utf-8"?>' . PHP_EOL;
        $xml .= self::encode($obj, $root_node, $depth = 0);
        return $xml;
    }
    /**
     * Encode an object as XML string
     *
     * @param Object|array $data
     * @param string $node
     * @param int $depth Used for indentation
     * @return string $xml
     */
    private static function encode($data, $node, $depth) {
        $xml = str_repeat("\t", $depth);
        $xml .= "<{$node}>" . PHP_EOL;
        foreach($data as $key => $val) {
            if(is_array($val) || is_object($val)) {
                $xml .= self::encode($val, $key, ($depth + 1));
            } else {
                $xml .= str_repeat("\t", ($depth + 1));
                $xml .= "<{$key}>" . htmlspecialchars($val) . "</{$key}>" . PHP_EOL;
            }
        }
        $xml .= str_repeat("\t", $depth);
        $xml .= "</{$node}>" . PHP_EOL;
        return $xml;
    }
}