php - 如何获取的xml属性？

Question

我无法找出或找出如何使用PHP permission="allowed"从此xml解析simplexml_load_file值。

基本结构是

<?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" gd:etag="W/&quot;DkEDSH47eCp7I2A9WhJbEEQ.&quot;">
<yt:accessControl action="comment" permission="allowed" />
<yt:accessControl action="commentVote" permission="allowed" />
<yt:accessControl action="videoRespond" permission="moderated" />
<yt:accessControl action="rate" permission="allowed" />
<yt:accessControl action="embed" permission="allowed" />
<yt:accessControl action="list" permission="allowed" />
<yt:accessControl action="autoPlay" permission="allowed" />
<yt:accessControl action="syndicate" permission="allowed" />

如何获得最后一行上 permission=allowed属性的值？

Answer 1

您想使用 XPath 来检索记录，这是一种XML查询语言。

请参阅SimpleXMLElement's xpath()和registerXPathNamespace()方法。
W3Schools解释XPath's syntax here。

对于此XML

$xml = <<<EOD
<book xmlns:chap="http://example.org/chapter-title">
   <title>My Book</title>
</book>
EOD;

您将注册一个这样的 namespace :

$sxe = new SimpleXMLElement($xml);
$sxe->registerXPathNamespace('c', 'http://example.org/chapter-title');
$result = $sxe->xpath('//c:title');