ResponseClassInterface.php

<?php
class Bundles implements ResponseClassInterface
{
    protected $bundles = array();

    public function addBundle($bundle)
    {
        $this->bundles[] = $bundle;
    }

    /**
     * Create a response model object from a completed command
     *
     * @param OperationCommand $command That serialized the request
     *
     * @return self
     */
    public static function fromCommand(OperationCommand $command)
    {
        $bundlesObject = new self();
        $xml = new \DOMDocument();
        $xml->loadXML($command->getResponse()->getBody(true));

        $xpath = new \DOMXPath($xml);
        foreach ($xpath->query('/bundles/bundle/@href') as $bundle) {
            $bundlesObject->addBundle($bundle->value);
        }
        return $bundlesObject;
    }
}