parse XML from URL (via SOAP)

I am attempting to build out a dashboard widget that will perform a validation check on a site RSS feed using the W3 Validator. Their API docs ( provide the method. Here is my function to get the data:

    $feed       = '';
    $request    = new WP_Http;
    $url        = ''.urlencode($feed).'&output=soap12';
    $response   = wp_remote_get ( $url );

    if( is_wp_error( $response ) ) {
        echo '<p>Sorry, there was an error with your request.</p>';
    } else {
        $feed_data  = $response['body'];

Here is the return:

For the life of me, I cannot seem to parse out that XML properly. Is there a 3rd party library I should be using, or is there a native WP function that will handle this?

Solutions Collecting From Web of "parse XML from URL (via SOAP)"

Lots of places in WordPress use xml_parse including the Atom library, the XML-RPC Library that we use, and SimplePie

The oembed class uses SimpleXML.

The WordPress Importer and Jetpack actually use both (Jetpack for different things, and the importer tries to use SimpleXML and falls back if it doesn’t exist).

Basically, there’s nothing built into WordPress, it just uses what’s built into PHP. I personally like (and use) SimpleXML as long as the XML isn’t going to be too big (I mean really big), just because you can simply pass the whole XML string to it and get back an object you can work with.