PHP：检索DOMElement的所有声明的命名空间 [英] PHP: retrieve all declared namespaces of a DOMElement

问题描述

我正在使用 DOM扩展程序来解析包含<一个href =http://en.wikipedia.org/wiki/Xml_namespace =nofollow noreferrer> xml命名空间。我会想到，命名空间声明就像任何其他属性一样对待，但我的测试似乎不同意。我有一个这样的文档：

 < rdf：RDF 
 xmlns：rdf =http： /www.w3.org/1999/02/22-rdf-syntax-ns#
 xmlns =http://purl.org/rss/1.0/
 xmlns：taxo =http ：//purl.org/rss/1.0/modules/taxonomy/
 xmlns：dc =http://purl.org/dc/elements/1.1/
 xmlns：syn =http ：//purl.org/rss/1.0/modules/syndication/
 xmlns：prism =http://purl.org/rss/1.0/modules/prism/
 xmlns：admin = http://webns.net/mvcb/
> 
  

此类测试代码如下：

  $ doc = new DOMDocument（）; 
 $ doc-> loadXml（file_get_contents（'/ home / soulmerge / tmp / rss1.0 / recent.xml'））; 
 $ root = $ doc-> documentElement; 
 var_dump（$ root-> tagName）; 
＃prints'string（7）rdf：RDF'
 var_dump（$ root-> attributes-> item（0））; 
＃prints'NULL'
 var_dump（$ root-> getAttributeNode（'xmlns'））; 
＃prints'object（DOMNameSpaceNode）＃3（0）{}'
  

所以问题是：

1. 有谁知道在哪里可以找到 DOMNameSpaceNode 的文档？ 在php.net上搜索不产生任何有用的结果。


2. 如何从该DOMElement中提取所有这些命名空间声明？

解决方案

除非有更直接的方式，否则可以使用XPath及其命名空间轴。

例如

 <？php 
 $ doc = new DOMDocument; 
 $ doc-> loadxml（'< rdf：RDF 
 xmlns：rdf =http://www.w3.org/1999/02/22-rdf-syntax-ns#
 xmlns =http://purl.org/rss/1.0/
 xmlns：taxo =http://purl.org/rss/1.0/modules/taxonomy/
 xmlns ：dc =http://purl.org/dc/elements/1.1/
 xmlns：syn =http://purl.org/rss/1.0/modules/syndication/
 xmlns ：prism =http://purl.org/rss/1.0/modules/prism/
 xmlns：admin =http://webns.net/mvcb/
> 
 ... 
< / rdf：RDF>'）; 
 $ context = $ doc-> documentElement; 
 
 $ xpath = new DOMXPath（$ doc）; 
 foreach（$ xpath-> query（'namespace :: *'，$ context）as $ node）{
 echo $ node-> nodeValue，\\\
; 
} 
  

打印

  http://www.w3.org/XML/1998/namespace 
 http://webns.net/mvcb/ 
 http://purl.org/ rss / 1.0 / modules / prism / 
 http://purl.org/rss/1.0/modules/syndication/ 
 http://purl.org/dc/elements/1.1/ 
 http://purl.org/rss/1.0/modules/taxonomy/ 
 http://purl.org/rss/1.0/ 
 http://www.w3.org/1999/02/ 22-rdf-syntax-ns＃
  

---

编辑和btw：我还没有找到DOMNameSpaceNode的文档。但是您可以从ext / dom / php_dom.c中的源代码中扣除（部分）其功能

它似乎没有暴露任何方法并公开属性

 nodeName，nodeValue，nodeType，
prefix，localName，namespaceURI，
 ownerDocument，parentNode
  

由与相应的DOMNode属性相同的功能处理。 p>

I am using the DOM extension to parse an xml file containing xml namespaces. I would have thought that namespace declarations are treated just like any other attribute, but my tests seem to disagree. I have a document that starts like this:

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns="http://purl.org/rss/1.0/"
    xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:syn="http://purl.org/rss/1.0/modules/syndication/"
    xmlns:prism="http://purl.org/rss/1.0/modules/prism/"
    xmlns:admin="http://webns.net/mvcb/"
    >

And a test code like this:

$doc = new DOMDocument();
$doc->loadXml(file_get_contents('/home/soulmerge/tmp/rss1.0/recent.xml'));
$root = $doc->documentElement;
var_dump($root->tagName);
# prints 'string(7) "rdf:RDF"'
var_dump($root->attributes->item(0));
# prints 'NULL'
var_dump($root->getAttributeNode('xmlns'));
# prints 'object(DOMNameSpaceNode)#3 (0) {}'

So the questions are:

1. Does anyone know where could I find the documentation of DOMNameSpaceNode? A search on php.net does not yield any useful result.
2. How do I extract all those namespace declarations from that DOMElement?

解决方案

Unless there is a more direct way you can use XPath and its namespace axis.
e.g.

<?php
$doc = new DOMDocument;
$doc->loadxml('<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns="http://purl.org/rss/1.0/"
    xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:syn="http://purl.org/rss/1.0/modules/syndication/"
    xmlns:prism="http://purl.org/rss/1.0/modules/prism/"
    xmlns:admin="http://webns.net/mvcb/"
    >
...
</rdf:RDF>');
$context = $doc->documentElement;

$xpath = new DOMXPath($doc);
foreach( $xpath->query('namespace::*', $context) as $node ) {
  echo $node->nodeValue, "\n";
}

prints

http://www.w3.org/XML/1998/namespace
http://webns.net/mvcb/
http://purl.org/rss/1.0/modules/prism/
http://purl.org/rss/1.0/modules/syndication/
http://purl.org/dc/elements/1.1/
http://purl.org/rss/1.0/modules/taxonomy/
http://purl.org/rss/1.0/
http://www.w3.org/1999/02/22-rdf-syntax-ns#

---

edit and btw: I haven't found documentation for DOMNameSpaceNode either. But you can "deduct" (parts of) its functionality from the source code in ext/dom/php_dom.c
It doesn't seem to expose any methods and exposes the properties

"nodeName", "nodeValue", "nodeType",
"prefix", "localName", "namespaceURI",
"ownerDocument", "parentNode"

all handled by the same functions as the corresponding DOMNode properties.

这篇关于PHP：检索DOMElement的所有声明的命名空间的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！