如何获取 RSS 提要的特定于 iTunes 的子节点？

Question

I'm trying to process an RSS feed using PHP and there are some tags such as 'itunes:image' which I need to process. The code I'm using is below and for some reason these elements are not returning any value. The output is length is 0.

How can I read these tags and get their attributes?

$f = $_REQUEST['feed'];
$feed = new DOMDocument();
$feed->load($f);
$items = $feed->getElementsByTagName('channel')->item(0)->getElementsByTagName('item');

foreach($items as $key => $item) 
{
    $title = $item->getElementsByTagName('title')->item(0)->firstChild->nodeValue;
    $pubDate = $item->getElementsByTagName('pubDate')->item(0)->firstChild->nodeValue;
    $description = $item->getElementsByTagName('description')->item(0)->textContent; // textContent

    $arrt = $item->getElementsByTagName('itunes:image');
    print_r($arrt);
}

Answer 1

getElementsByTagName is specified by DOM, and PHP is just following that. It doesn't consider namespaces. Instead, use getElementsByTagNameNS , which requires the full namespace URI (not the prefix). This appears to be http://www.itunes.com/dtds/podcast-1.0.dtd *. So:

    $img = $item->getElementsByTagNameNS('http://www.itunes.com/dtds/podcast-1.0.dtd', 'image');
    // Set preemptive fallback, then set value if check passes
    urlImage = '';
    if ($img) {
      $urlImage = $img->getAttribute('href');
    }

Or put the namespace in a constant.

You might be able to get away with simply removing the prefix and getting all image tags of any namespace with getElementsByTagName .

Make sure to check whether a given item has an itunes:image element at all (example now given); in the example podcast, some don't, and I suspect that was also giving you trouble. (If there's no href attribute, getAttribute will return either null or an empty string per the DOM spec without erroring out.)

_{* In case you're wondering, there is no actual DTD file hosted at that location, and there hasn't been for about ten years.}

Answer 2

<?php
$rss_feed = simplexml_load_file("url link");
if(!empty($rss_feed)) {
$i=0;
foreach ($rss_feed->channel->item as $feed_item) {    
?>
            
<?php echo $rss_feed->children('itunes', true)->image->attributes()->href;?>

<?php
}
?>