如何用PHP解析YouTube XML，包括名称空间描述

我试图使用PHP的SimpleXMLElement解析YouTube频道提要并包含描述。我可以很容易地获得标题和视频url

这是我能得到描述的东西

$channel_id = 'UCtNjkMLQQOX251hjGqimx2w';
$yt_url = 'https://www.youtube.com/feeds/videos.xml?channel_id=';
$xml_str = file_get_contents($yt_url.$channel_id);
$xml = new SimpleXMLElement($xml_str);
$xml->registerXPathNamespace('prefix', 'http://www.w3.org/2005/Atom');
$result = $xml->xpath("//media:description");
foreach($result as $r){
 print $r;
 print '<br />';
}

$channel_id='UCtNjkMLQQOX251hjGqimx2w'；
$yt_https://www.youtube.com/feeds/videos.xml?channel_id=';
$xml\u str=file\u get\u contents（$yt\u url.$channel\u id）；
$xml=新的simplexmlement（$xml\u str）；
$xml->registerXPathNamespace（'前缀'，'http://www.w3.org/2005/Atom');
$result=$xml->xpath（//media:description”）；
foreach（结果为$r）{
打印$r；
打印“
”；
}

来自YouTube的原始xml看起来像这样

 <entry>
  <id>yt:video:OTYFJaT-Glk</id>
  <yt:videoId>OTYFJaT-Glk</yt:videoId>
  <yt:channelId>UCtNjkMLQQOX251hjGqimx2w</yt:channelId>
  <title>Guitar E.R. - Setting up wood shop for O Positive custom speaker cabinets.</title>
  <link rel="alternate" href="https://www.youtube.com/watch?v=OTYFJaT-Glk"/>
  <author>
   <name>Guitar ER</name>
   <uri>https://www.youtube.com/channel/UCtNjkMLQQOX251hjGqimx2w</uri>
  </author>
  <published>2020-10-18T16:38:51+00:00</published>
  <updated>2020-10-20T01:04:59+00:00</updated>
  <media:group>
   <media:title>Guitar E.R. - Setting up wood shop for O Positive custom speaker cabinets.</media:title>
   <media:content url="https://www.youtube.com/v/OTYFJaT-Glk?version=3" type="application/x-shockwave-flash" width="640" height="390"/>
   <media:thumbnail url="https://i4.ytimg.com/vi/OTYFJaT-Glk/hqdefault.jpg" width="480" height="360"/>
   <media:description>In this video Doctor John Moran of Guitar E.R. gives us a glimpse into the new wood shop where he will be building custom guitar and bass cabinets, likely under the name O Positive Cabinets.</media:description>
   <media:community>
    <media:starRating count="0" average="0.00" min="1" max="5"/>
    <media:statistics views="22"/>
   </media:community>
  </media:group>
 </entry>
 <entry>

yt：视频：OTYFJaT Glk
奥蒂夫贾特Glk
UCTNJKMLQOX251HJGQIMX2W
吉他E.R.-为O-Positive定制音箱柜建立木材车间。
';
打印“”；
}
?>

$xml_str = file_get_contents($yt_url.$channel_id);
$xml = new SimpleXMLElement($xml_str);
foreach($xml->entry as $entry){
    print $entry->title;
    print '<br />';
    print $entry->author->uri;
    print '<br />';
}

<?
$channel_id = 'UCtNjkMLQQOX251hjGqimx2w';
$yt_url = 'https://www.youtube.com/feeds/videos.xml?channel_id=';

$xml_str = file_get_contents($yt_url.$channel_id);
$xml = new SimpleXMLElement($xml_str);
$xml->registerXPathNamespace('prefix', 'http://www.w3.org/2005/Atom');

$yt_data = array();
foreach($xml->entry as $entry){

    $videoid = (string)$entry->children('yt', true)->videoId;
    $yt_data[] = array(
        'id' => $videoid,
        'title' => (string)$entry->title,
        'description' => (string)$entry->children('media', true)->group->description,
        'img' => (string)'https://img.youtube.com/vi/'.$videoid.'/maxresdefault.jpg',
        'thumb' => (string)'https://img.youtube.com/vi/'.$videoid.'/mqdefault.jpg',
        'published' => (string)$entry->published,
        'updated' => (string)$entry->updated,
        'channel' => (string)$entry->children('yt', true)->channelId,
        'author' => (string)$entry->author->name,
        'uri' => (string)$entry->author->uri,
        'views' => (string)$entry->children('media', true)->group->community->statistics->attributes()['views'],
        'ratings_count' => (string)$entry->children('media', true)->group->community->starRating->attributes()['count'],
        'ratings_avg' => (string)$entry->children('media', true)->group->community->starRating->attributes()['average'],
    );
    
}

foreach($yt_data as $yt){
    print '<div class="ytVidWrap">';
    print '<a href="https://www.youtube.com/watch?v='.$yt['id'].'" target="_blank">';
    print '<img src="'.$yt['thumb'].'" alt="YouTube Video" />';
    print '<h1>'.$yt['title'].'</h1>';
    print '<p>'.$yt['description'].'</p>';
    print '<p>'.$yt['views'].' views &bull; '.date('M j, Y',strtotime($yt['published'])).'</p>';
    print '</a>';
    print '</div>';
}
?>