SimpleXML: How to parse nodenames including dots with xpath query - php

Question

I have to parse the following XML:
<BMECAT version="2005" xmlns="http://www.bmecat.org/bmecat/2005fd">
<T_NEW_CATALOG prev_version="0">
<PRODUCT>
<NAME>Test</NAME>
<USER_DEFINED_EXTENSIONS>
<UDX.VENDOR.ATTRIBUTE lang="de">German</UDX.VENDOR.ATTRIBUTE>
<UDX.VENDOR.ATTRIBUTE lang="en">English</UDX.VENDOR.ATTRIBUTE>
</USER_DEFINED_EXTENSIONS>
</PRODUCT>
</T_NEW_CATALOG>
</BMECAT>
I need to get the value "German" via xpath. Everything I have tried so far didn't work so I need some help. I think the problem is that the tagname includes dots. I have found no way to escape the xpath expression.

Answer 1

The XML you show cannot be parsed because it is malformed (USER_DEFINED_EXTENSIONS is not closed properly). Assuming well-formed input, you could use DOMDocument instead of SimpleXML:
<?php
$xml = <<<'XML'
<BMECAT version="2005" xmlns="http://www.bmecat.org/bmecat/2005fd">
<T_NEW_CATALOG prev_version="0">
<PRODUCT>
<NAME>Test</NAME>
<USER_DEFINED_EXTENSIONS>
<UDX.VENDOR.ATTRIBUTE lang="de">German</UDX.VENDOR.ATTRIBUTE>
<UDX.VENDOR.ATTRIBUTE lang="en">English</UDX.VENDOR.ATTRIBUTE>
</USER_DEFINED_EXTENSIONS>
</PRODUCT>
</T_NEW_CATALOG>
</BMECAT>
XML;
$dom = new DOMDocument();
$dom->loadXML($xml);
$xpath = new DOMXPath($dom);
$xpath->registerNamespace("bme",
"http://www.bmecat.org/bmecat/2005fd");
$expression = 'string(
/bme:BMECAT
/bme:T_NEW_CATALOG
/bme:PRODUCT
/bme:USER_DEFINED_EXTENSIONS
/bme:UDX.VENDOR.ATTRIBUTE[#lang = "de"]
)';
var_dump($xpath->evaluate($expression));
And the result will be
German
If you need to use SimpleXML, you really need to show your current PHP code.