create_rss_feed_recursive.php

<?php


$xml = new SimpleXMLElement(
  '<?xml version="1.0" encoding="utf-8"?>
  <rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/">
  <channel>
  </channel>
  </rss>');

$channel = $xml->channel;

// .. fetch items from database

foreach ($items as $item)
{
  // image or clip
  if (in_array($item->type, array('image','clip')))
  {
    $feeditem = $channel->addChild('item');
    $feeditem->addChild('title', $item->title);
    $feeditem->addChild('description', $item->title);
    $feeditem->addChild('link', $item->get_fullpath());
    $guid = $feeditem->addChild('guid', $item->get_guid());
    $guid->addAttribute('isPermalink', 'false');

    $media_content = $feeditem->addChild('media:content', '', 'http://search.yahoo.com/mrss/');
    $media_content->addAttribute('url', $item->get_fullpath());
    $media_content->addAttribute('medium', $item->get_feedtype());
    if ($item->type=='image') $media_content->addAttribute('duration', $item->duration);
  }

  // external feed
  if ($item->type == 'feed')
  {    
    $feedxml = simplexml_load_file($item->filename);
    if ($feedxml == false) die('cant read feed');

    foreach($feedxml->channel->item as $feeditem)
    {
      xml_adopt($channel, $feeditem);
    }
  }
}

// debug pretty print
$dom = new DOMDocument("1.0");
$dom->preserveWhiteSpace = false;
$dom->formatOutput = true;
$dom->loadXML($xml->asXML());
echo "<pre>";
echo htmlspecialchars( var_export($dom->saveXML(), true) );


// ----------------------------------------------------------------------

function xml_adopt($root, $new, $namespace = null) {
    // first add the new node
    $node = $root->addChild($new->getName(), (string) $new, $namespace);
    // add any attributes for the new node
    foreach($new->attributes() as $attr => $value) {
        $node->addAttribute($attr, $value);
    }
    // get all namespaces, include a blank one
    $namespaces = array_merge(array(null), $new->getNameSpaces(true));
    // add any child nodes, including optional namespace
    foreach($namespaces as $space) {
      foreach ($new->children($space) as $child) {
        xml_adopt($node, $child, $space);
      }
    }
}

// ----------------------------------------------------------------------

output.xml

<?xml version="1.0" encoding="utf-8"?>
<rss xmlns:media="http://search.yahoo.com/mrss/" version="2.0">
  <channel>
    <item>
      <title>cheese.jpg</title>
      <description>cheese.jpg</description>
      <link>http://local.dev/zwartav-rss/feedmanager/media/cheese.jpg</link>
      <guid isPermalink="false">cb3415a3e8660538c7dcc20d91b9fc28e8063085</guid>
      <media:content url="http://local.dev/zwartav-rss/feedmanager/media/cheese.jpg" medium="image" duration="20"/>
      <feed_id>1f506a1261ee0374caddede812524456</feed_id>
    </item>
    <item>
      <title>cocacola.jpg</title>
      <description>cocacola.jpg</description>
      <link>http://local.dev/zwartav-rss/feedmanager/media/cocacola.jpg</link>
      <guid isPermalink="false">cd7e0cef4f98c8cec7fb7c6618ba3526d113ad92</guid>
      <media:content url="http://local.dev/zwartav-rss/feedmanager/media/cocacola.jpg" medium="image" duration="15"/>
      <feed_id>1f506a1261ee0374caddede812524456</feed_id>
    </item>
    <item>
      <title>video.mp4</title>
      <description>video.mp4</description>
      <link>http://local.dev/zwartav-rss/feedmanager/media/video.mp4</link>
      <guid isPermalink="false">f1c095f4b1c923dbbf459da6eff04b727dd1f35c</guid>
      <media:content url="http://local.dev/zwartav-rss/feedmanager/media/video.mp4" medium="video"/>
      <feed_id>1f506a1261ee0374caddede812524456</feed_id>
    </item>
  </channel>
</rss>