如何使用simpeXML從youtube API獲取視頻持續時間？

Question

我已經使用這個代碼

public function getVideoLength($id) 
    { 
     $this->getVideoFeed($id); 
     if ($this->xmlEntry == null) return 0; 
     $duration = $this->xmlEntry->media['group']->yt['duration'];   
     return $duration; 
    } 

得到了來自YouTube

<?xml version="1.0" encoding="UTF-8"?> 
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:media="http://search.yahoo.com/mrss/" xmlns:gd="http://schemas.google.com/g/2005" xmlns:yt="http://gdata.youtube.com/schemas/2007"> 
    <id>http://gdata.youtube.com/feeds/api/videos/9mZb6PZM4FU</id> 
    <published>2010-01-09T19:38:15.000Z</published> 
    <updated>2013-07-17T06:51:32.000Z</updated> 
    <category scheme="http://schemas.google.com/g/2005#kind" term="http://gdata.youtube.com/schemas/2007#video" /> 
    <category scheme="http://gdata.youtube.com/schemas/2007/categories.cat" term="Entertainment" label="Розваги" /> 
    <title type="text">Каратэ</title> 
    <content type="text">Сцена из фильма "Не бойся, я с тобой"</content> 
    <link rel="alternate" type="text/html" href="http://www.youtube.com/watch?v=9mZb6PZM4FU&amp;feature=youtube_gdata" /> 
    <link rel="http://gdata.youtube.com/schemas/2007#video.responses" type="application/atom+xml" href="http://gdata.youtube.com/feeds/api/videos/9mZb6PZM4FU/responses" /> 
    <link rel="http://gdata.youtube.com/schemas/2007#video.related" type="application/atom+xml" href="http://gdata.youtube.com/feeds/api/videos/9mZb6PZM4FU/related" /> 
    <link rel="http://gdata.youtube.com/schemas/2007#mobile" type="text/html" href="http://m.youtube.com/details?v=9mZb6PZM4FU" /> 
    <link rel="self" type="application/atom+xml" href="http://gdata.youtube.com/feeds/api/videos/9mZb6PZM4FU" /> 
    <author> 
     <name>Lefan123</name> 
     <uri>http://gdata.youtube.com/feeds/api/users/Lefan123</uri> 
    </author> 
    <gd:comments> 
     <gd:feedLink rel="http://gdata.youtube.com/schemas/2007#comments" href="http://gdata.youtube.com/feeds/api/videos/9mZb6PZM4FU/comments" countHint="80" /> 
    </gd:comments> 
    <media:group> 
     <media:category label="Розваги" scheme="http://gdata.youtube.com/schemas/2007/categories.cat">Entertainment</media:category> 
     <media:content url="http://www.youtube.com/v/9mZb6PZM4FU?version=3&amp;f=videos&amp;app=youtube_gdata" type="application/x-shockwave-flash" medium="video" isDefault="true" expression="full" duration="174" yt:format="5" /> 
     <media:content url="rtsp://r4---sn-4g57kuek.c.youtube.com/CiILENy73wIaGQlV4Ez26Ftm9hMYDSANFEgGUgZ2aWRlb3MM/0/0/0/video.3gp" type="video/3gpp" medium="video" expression="full" duration="174" yt:format="1" /> 
     <media:content url="rtsp://r4---sn-4g57kuek.c.youtube.com/CiILENy73wIaGQlV4Ez26Ftm9hMYESARFEgGUgZ2aWRlb3MM/0/0/0/video.3gp" type="video/3gpp" medium="video" expression="full" duration="174" yt:format="6" /> 
     <media:description type="plain">Сцена из фильма "Не бойся, я с тобой"</media:description> 
     <media:keywords /> 
     <media:player url="http://www.youtube.com/watch?v=9mZb6PZM4FU&amp;feature=youtube_gdata_player" /> 
     <media:thumbnail url="http://i1.ytimg.com/vi/9mZb6PZM4FU/0.jpg" height="360" width="480" time="00:01:27" /> 
     <media:thumbnail url="http://i1.ytimg.com/vi/9mZb6PZM4FU/1.jpg" height="90" width="120" time="00:00:43.500" /> 
     <media:thumbnail url="http://i1.ytimg.com/vi/9mZb6PZM4FU/2.jpg" height="90" width="120" time="00:01:27" /> 
     <media:thumbnail url="http://i1.ytimg.com/vi/9mZb6PZM4FU/3.jpg" height="90" width="120" time="00:02:10.500" /> 
     <media:title type="plain">Каратэ</media:title> 
     <yt:duration seconds="174" /> 
    </media:group> 
    <gd:rating average="4.934732" max="5" min="1" numRaters="429" rel="http://schemas.google.com/g/2005#overall" /> 
    <yt:statistics favoriteCount="0" viewCount="215169" /> 
</entry> 

我試圖獲取時間這個XML響應，但持續時間$爲空。 如何得到它？

Answer 1

xml中的冒號用於定義不同的名稱空間。您需要將命名空間切換到媒體才能訪問持續時間。

嘗試使用：

$this->xmlEntry->children('media', true)->group->children('yt', true)->duration->attributes()["seconds']; 

嘗試在這裏閱讀更多關於它：http://www.w3schools.com/xml/xml_namespaces.asp和PHP library for parsing XML with a colons in tag names?

還要注意的是秒的持續時間標籤的屬性，您試圖訪問它的價值。