Mark Flint

Here are two examples of getting attribute values using an xpath query: one using simpleXML and one using DOM document. Both queries are on namespaces within the XML file.

First here’s the DOM Document version:

$dom = new DomDocument();
// it's possible to use the static method ::load instead of intantiating
$dom->load('http://api.flickr.com/services/feeds/groups_pool.gne?id=12345678@N00&format=rss_200');
$xpath = new DOMXPath($dom);
$result = $xpath->query("//media:thumbnail/@url");
foreach ($result as $val) {
    // make an array of thumbnail URLs from a Flickr group
    $thumbsArray[] = $val->nodeValue;
}

… and the SimpleXML version:

$xml = simplexml_load_file('http://api.flickr.com/services/feeds/groups_pool.gne?id=12345678@N00&format=rss_200');
$result = $xml->xpath('//media:thumbnail/@url');
foreach ($result as $val) {
    // make an array of thumbnail URLs from a Flickr group
    $thumbsA[] = (string)$val['url'];
}

Here’s a simpleXML script I used to parse a feed. There are MP3 links that are under the namespace xmlns:media=”http://search.yahoo.com/mrss/”. The links are in the feed like this:

<media:group>
    <media:content url='linkformp3.mp3' />
</media:group>

To get at the url attribute you first have to access the ‘media’ namespace by using children('media',true). This tells the parser to find children of the namespace prefix ‘media’. Another way to do this is to use the url declared for the namespace, but using children(‘media’,true) seems easier. Here’s the full script:

<?php
$file = 'http://www.ucbmedia.co.uk/feeds/wft/index.php';
$xml = simplexml_load_file($file, 'SimpleXMLElement', LIBXML_NOCDATA);

foreach ($xml->channel->item as $item) {
    echo "<b>".$item->title."</b><br><br>";
    echo $item->description."<br><br>";
    echo $item->pubDate."<br><br>";
    // get children for namespace prefixed 'media'
    $media = $item->children('media',true);
    $mp3 = $media->group->content->attributes();
    echo $mp3['url']."<br><hr><br><br>";
}
?>

Also notice the way of loading a feed and preserving CDATA in simpleXML, simplexml_load_file($file, 'SimpleXMLElement', LIBXML_NOCDATA);