Classe para gerar XML

XMLElement.php

<?php 

class XMLElement
{
	private $tag = null;
	private $value = null;
	private $childs = [];
	private $attributes = [];
	private $isRoot = true;
	private $isCDATA = false;

	public function __construct($tag)
	{
		$this->tag = $tag;
	}

	public function addAttribute($name, $value = null)
	{
		$this->attributes[$name] = $value;
	}

	public function addChild($name, $value = null)
	{
		$child = new XMLElement($name, $value);
		$child ->isRoot = false;
		$child ->value = $value;
		$this->childs[] = $child;
		return $child;
	}

	public function addChildCDATA($name, $value = null)
	{
		$child = $this->addChild($name, $value);
		$child->isCDATA = true;
		return $child;
	}

	public function asXML()
	{
		$xml = $this->isRoot ? '<?xml version="1.0" encoding="iso-8859-1"?>' . NL : '';
		if(count($this->childs)) {
			$xml .= '<' . $this->tag . $this->getAttributes() . '>' . NL;
			foreach ($this->childs as $child) {
				$xml .= "\t" . $child->asXML();
			}
			$xml .= "\t" . '</' . $this->tag . '>' . NL;
		} else if($this->value) {
			$xml .= "\t" . '<' . $this->tag . $this->getAttributes() . '>';
			$xml .= $this->isCDATA ? '<![CDATA['. $this->value . ']]>' : htmlentities($this->value);
			$xml .= '</' . $this->tag . '>' . NL;
		} else {
			$xml .= "\t" . '<' . $this->tag . $this->getAttributes() . '/>' . NL;
		}
		return $xml;
	}

	private function getAttributes()
	{
		$attributes = [];
		foreach ($this->attributes as $key => $value) {
			$attributes[] = $value ? $key . '="' . $value . '"' : $key;
		}
		return (count($attributes) ? ' ' : '') . implode(' ', $attributes);
	}
}