PHP updating xml CDATA fields with DOMdocument

Question

I have the following XML data:

<?xml version="1.0" encoding="utf-8"?>
<source>
    <publisher>some-data</publisher>
    <publisherurl>some-data</publisherurl>
    <lastBuildDate>a-date</lastBuildDate>
    <element>
        <sub-element><![CDATA[some-data]]></sub-element>
    </element>
</source>

I'm trying to use PHP's built in DOMdocument parser to update the text inside sub-element.

I've tried:

$dom=new DOMDocument();
$dom->load("document.xml");

$ele=$root->getElementsByTagName('element');
foreach ($ele as $e) {
    $e->getElementsByTagName('sub-element')->item(0)->nodeValue = "new val";
}

this kind of works but it removes the CDATA and just replaces it with new-val. I want to preserve the CDATA field so I tried the following:

$dom=new DOMDocument();
$dom->load("document.xml");

$ele=$root->getElementsByTagName('element');
foreach ($ele as $e) {  
    $sub=$e->getElementsByTagName('sub-element');   
    foreach($sub->childNodes as $child) {
        if ($child->nodeType == XML_CDATA_SECTION_NODE) {
            $child->nodeValue = 'new-val';
        }
    }
}

This seems like it should work but PHP returns the following Notice

Undefined property: DOMNodeList::$childNodes

Feel like I'm on the right path but I just can't figure out what I'm doing wrong here. Does anyone know how to fix?

My end goal output is:

<?xml version="1.0" encoding="utf-8"?>
<source>
    <publisher>some-data</publisher>
    <publisherurl>some-data</publisherurl>
    <lastBuildDate>a-date</lastBuildDate>
    <element>
        <sub-element><![CDATA[new-val]]></sub-element>
    </element>
</source>

Felippe Duarte · Accepted Answer · 2018-01-24 21:35:59Z

3

You need to compare against firstChild

$xml = '<?xml version="1.0" encoding="utf-8"?>
<source>
    <publisher>some-data</publisher>
    <publisherurl>some-data</publisherurl>
    <lastBuildDate>a-date</lastBuildDate>
    <element>
        <sub-element><![CDATA[some-data]]></sub-element>
    </element>
    <element>
        <sub-element>some-other-data</sub-element>
    </element>
</source>';

$dom = new DOMDocument();
$dom->loadXML($xml);

$ele=$dom->getElementsByTagName('element');
foreach ($ele as $e) {
    $item = $e->getElementsByTagName('sub-element')->item(0);
    if($item->firstChild->nodeType == XML_CDATA_SECTION_NODE) { //<------
        //it's CDATA do whatever
         $item->firstChild->nodeValue = "new val";
    } else {
        //it's not , do something else
        $item->nodeValue = "new val";
    }
}
echo "<pre>";
print_r(htmlentities($dom->saveXML()));
echo "</pre>";

Output:

<?xml version="1.0" encoding="utf-8"?>
<source>
    <publisher>some-data</publisher>
    <publisherurl>some-data</publisherurl>
    <lastBuildDate>a-date</lastBuildDate>
    <element>
        <sub-element><![CDATA[new val]]></sub-element>
    </element>
    <element>
        <sub-element>new val</sub-element>
    </element>
</source>

PS: if you don't have to make a distinction between CDATA or not, just use firstChild

foreach ($ele as $e) {
    $item = $e->getElementsByTagName('sub-element')->item(0);
    $item->firstChild->nodeValue = "new val";
}

edited Jan 24, 2018 at 21:35

answered Jan 24, 2018 at 21:22

Felippe Duarte

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3 Comments

Austin Over a year ago

The output I'm looking for would be this: <sub-element><![CDATA[new val]]></sub-element> How do I do that?

Felippe Duarte Over a year ago

$item->firstChild->nodeValue = "new val"; Edited, take a look

Felippe Duarte Over a year ago

Or if can just ignore the comparison and use firstChild all the time

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