如何查询<entry>来自 ATOM 提要的节点 [英] How to query the <entry> nodes from an ATOM feed

问题描述

我可以查询 RSS 提要中的 description 节点并返回如下结果:

I can query the description nodes in an RSS feed and return a result like this:

$xpath = new DOMXPath($xmlDoc);
$items = $xpath->query('/rss/channel/item/description/..');

foreach($items as $number => $item){}

但是当我从这样的 Atom 提要中查询 entry 节点时，它没有返回任何内容(我遵循与上述 RSS 相同的模式):

But it returns nothing when I query the entry nodes from an Atom feed like this (in which I follow the same pattern as RSS's above):

$xpath = new DOMXPath($xmlDoc);
$items = $xpath->query('/feed/entry/..');

foreach($items as $number => $item){}

我错过了什么?

推荐答案

没有 RSS 命名空间，而 Atom 元素在以下命名空间中:

There is no RSS namespace, whereas Atom elements are in the following namespace:

http://www.w3.org/2005/Atom 

您可以通过查看文档的 feed 元素来看到这一点，它可能如下所示:

You can see this by looking at your document's feed element, which probably looks something like this:

<feed xmlns="http://www.w3.org/2005/Atom">

在查询其中的元素之前，您需要注册此命名空间:

You need to register this namespace before querying for elements in it:

$xpath->registerNamespace('a', 'http://www.w3.org/2005/Atom'); 

然后在表达式中使用所选的命名空间前缀:

And then use the chosen namespace prefix in your expression:

$items = $xpath->query('/a:feed/a:entry');

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