How to prevent white space between XML nodes when traversing it?

Question

This is related to PHP Dom Document.

I have sample file like below

<?xml version="1.0" encoding="UTF-8"?>
<document>
    <items>
        <item class="pen">
            <no>1</no>
            <name>A</name>
            <price>10</price>
        </item>
        <item class="book">
            <no>2</no>
            <name>B</name>
            <price>20</price>
        </item>
        <item class="pen">
            <no>2</no>
            <name>C</name>
            <price>30</price>
        </item>
    </items>
</document>

PHP code

$nodeCount = $oElement;
$limitCount = 1;
$nodeCount = $nodeCount->nextSibling;
while($nodeCount && !empty($nodeCount) && $nodeCount->nodeType == 1 && !preg_match("/pen/",$this->GetNodeClass($nodeCount)))
{
    $limitCount++;
    $nodeCount = $nodeCount->nextSibling;
}

Here, GetNodeClass() checks for an attribute class and this is the culprit point from where error occurs

function GetNodeClass($oElement)
{
    //Error comes from below line when try to execute getAttribute() method on TextNode
    $class = $oElement->getAttribute('class');
    return $class;
}

When I traverse these elements, sometimes I receive errors like below

Fatal error: Call to undefined method DOMText::getAttribute() in

Then I have tried to solve it using below condition to prevent that error.

$node->nodeType == 1

In some cases it works properly but in some cases always it shows an error like explained. I knew that it comes because of some white space between nodes. But is there any other way to ignore those white space at the time of XML file reading? Because I have so much code written already so if there is some pin point solution for that.

I use DomDocument object for all this.

Any help will be appreciated.

Answer 1

I have just made a very simple code trying to reproduce your error but I was unable to, below follows the code which works just fine for me without any errors.

<?php

$dom = new DOMDocument;
$dom->preserveWhiteSpace = FALSE;
$dom->load('data.xml');

foreach ($dom->getElementsByTagName('item') as $item)
{
        if (!preg_match("/pen/",GetNodeClass($item)))
        #if ($item->getAttribute('class') == 'book')
        {
                        echo "no." . $item->childNodes->item(0)->nodeValue . "\n";
                        echo "Name: " . $item->childNodes->item(1)->nodeValue . "\n";
                        echo "Price: " . $item->childNodes->item(2)->nodeValue . "\n";
                        echo "----------------------------\n";
        }
}

function GetNodeClass($oElement)
{
    $class = $oElement->getAttribute('class');
    return $class;
}