Read XML File with DOMDocument in php - php

Question

I want to read this xml document:
<?xml version="1.0" encoding="UTF-8"?>
<tns:getPDMNumber xmlns:tns="http://www.testgroup.com/TestPDM" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.testgroup.com/TestPDM getPDMNumber.xsd ">
<tns:getPDMNumberResponse>
<tns:requestID>22222</tns:requestID>
<tns:pdmNumber>654321</tns:pdmNumber>
<tns:responseCode>0</tns:responseCode>
</tns:getPDMNumberResponse>
</tns:getPDMNumber>
I tried it this way:
$dom->load('response/17_getPDMNumberResponse.xml');
$nodes = $dom->getElementsByTagName("tns:requestID");
//$nodes = $dom->getElementsByTagName("tns:getPDMNumber");
//$nodes = $dom->getElementsByTagName("tns:getPDMNumberResponse");
foreach($nodes as $node)
{
$response=$node->getElementsByTagName("tns:getPDMNumber");
foreach($response as $info)
{
$test = $info->getElementsByTagName("tns:pdmNumber");
$pdm = $test->nodeValue;
}
}
the code never runs into the foreach loop.
Only for clarification my goal is to read the "tns:pdmNumber" node.
Have anybody a idea?
EDIT: I have also tried the commited lines.

Answer 1

The XML uses a namespace, so you should use the namespace aware methods. They have the suffix _NS.
$tns = 'http://www.testgroup.com/TestPDM';
$document = new DOMDocument();
$document->loadXml($xml);
foreach ($document->getElementsByTagNameNS($tns, "pdmNumber") as $node) {
var_dump($node->textContent);
}
Output:
string(6) "654321"
A better option is to use Xpath expression. They allow a more comfortable access to DOM nodes. In this case you have to register a prefix for the namespace that you can use in the Xpath expression:
$document = new DOMDocument();
$document->loadXml($xml);
$xpath = new DOMXpath($document);
$xpath->registerNamespace('t', 'http://www.testgroup.com/TestPDM');
var_dump(
$xpath->evaluate('string(/t:getPDMNumber/t:getPDMNumberResponse/t:pdmNumber)')
);

Answer 2

This:
$nodes = $dom->getElementsByTagName("tns:requestID");
you find all the requestID nodes, and try to loop on them. That's fine, but then you use that node as a basis to find any getPDMNumber nodes UNDER the requestID - but there's nothing - requestID is a terminal node. So
$response=$node->getElementsByTagName("tns:getPDMNumber");
finds nothing, and the inner loop has nothing to do.
It's like saying "Start digging a hole until you reach china. Once you reach China, keep digging until you reach Australia". But you can't keep digging - you've reached the "bottom", and the only thing deeper than China would be going into orbit.