PHP SimpleXML-> addChild-不需要的空名称空间属性 [英] PHP SimpleXML->addChild - unwanted empty namespace attribute

问题描述

我正在尝试使用SimpleXMLElement的SimpleXML的addChild方法(实际上是SimpleXMLElement的子类SimpleXMLIterator)来添加子元素.

I'm attempting to use SimpleXML's addChild method of the SimpleXMLElement (actually a SimpleXMLIterator which is a subclass of SimpleXMLElement) to add child elements.

我的问题是源文档包含带名称空间和不带名称空间的混合元素.这是一个简单(无双关语)示例:

My problem is that the source document contains a mixture of elements with namespaces and without. Here's a simple (no pun intended) example:

<?xml version="1.0" encoding="UTF-8"?>
  <ns1:a xmlns:ns1="http://www.abc.com">
</ns1:a>

PHP代码为:

$it = new SimpleXMLIterator ('./test.xml', 0, true);
$it->addChild('d', 'another!'); // adds new child element to parent's NS
$it->addChild('c', 'no namespace for me!', ''); // puts xmlns="" every time :(

//output xml in response:
header('Content-Type: text/xml');

echo $it->saveXML();

问题-正如评论所指出的-如果我想将没有命名空间的子元素放置在带有命名空间的父元素内，则每次都会得到一个空的XML命名空间属性(上述PHP代码的输出):

The problem - as the comment states - is that if I want to place a child element with no namespace inside of the parent element with a namespace, I get an empty XML namespace attribute every time (output of above PHP code):

<?xml version="1.0" encoding="UTF-8"?>
  <ns1:a xmlns:ns1="http://www.abc.com">
  <ns1:d>another!</ns1:d>
  <c xmlns="">no namespace for me!</c>
</ns1:a>

虽然Web浏览器和XML解析器(例如Xerces)似乎都不介意这种多余的标记，但我似乎有点讨厌，因为我似乎无法告诉它停止这样做.

While both web browsers as well as XML parsers (e.g. Xerces) don't seem to mind this superfluous markup, I find it slightly annoying that I can't seem to tell it to stop doing this.

任何人都有解决方案，还是我反应过度?

Anyone have a solution or am I over reacting?

:}

推荐答案

对于SimpleXML，c需要一个名称空间.如果您指定一个，它将获得xmlns属性，因为您之前未声明过指定的内容.如果未为c指定名称空间，则它将从父节点继承名称空间.这里唯一的选择是ns1. (这恰好是d.)

For SimpleXML c needs a namespace. If you specify one, it gets an xmlns attribute because what you specified has not been declared before. If you don't specify a namespace for c, it inherits the namespace from the parent node. The only option here is ns1. (This happens to d.)

为防止父名称空间的继承，并且省略空的xmlns，您需要在父名称空间使用xmlns="http://example.com"之类的名称空间.然后$it->addChild('c', 'no ns', 'http://example.com')给您<c>no ns</c>.

To prevent inhertance of the parent namespace and omit empty xmlns you'd need an namespace like xmlns="http://example.com" at the parent. Then $it->addChild('c', 'no ns', 'http://example.com') gives you <c>no ns</c>.

但是，您不能注入其他名称空间，例如使用addAttribute.您必须先处理输入文件，然后再用SimpleXML对其进行解析.对我来说，这似乎比从输出中删除所有空的xmlns属性还要难看.

However you cannot inject additional namespaces e.g. with addAttribute. You have to manipulate the input file before it's parsed by SimpleXML. To me this seems even more ugly than removing all empty xmlns attributes from the output.

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