解析symfony xml配置

Question

I have a symfony xml-config and need to parse it.

<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

<parameters>
    <parameter key="abcxyz" type="collection">
        <parameter key="abc" type="collection">
            <parameter key="a" type="string">a</parameter>
            <parameter key="b" type="string">b</parameter>
            <parameter key="c" type="constant">\My\Bundle\Type::TYPE_ABC</parameter>
        </parameter>
        <parameter key="xyz" type="collection">
            <parameter key="x" type="string">x</parameter>
            <parameter key="y" type="string">y</parameter>
            <parameter key="z" type="constant">\My\Bundle\Type::TYPE_XYZ</parameter>
        </parameter>
    </parameter>
</parameters>
</container>

and I need to get the values "abc" and "xyz". I tried to get it with

$simpleXml = simplexml_load_string(file_get_contents(__DIR__ . '/myConfig.xml');
var_dump($simpleXml->xpath('//parameters/parameter/parameter/@key'));

but the result is empty...

Answer 1

Add a namespace to the xml element and change the xpath query like this:

$simpleXml->registerXPathNamespace("s", "http://symfony.com/schema/dic/services");
$s=$simpleXml->xpath("//s:parameters/s:parameter/s:parameter/@key");
var_dump($s);

This will give the result that you want:

array (size=2)
  0 => 
    object(SimpleXMLElement)[6]
      public '@attributes' => 
        array (size=1)
          'key' => string 'abc' (length=3)
  1 => 
    object(SimpleXMLElement)[7]
      public '@attributes' => 
        array (size=1)
          'key' => string 'xyz' (length=3)