DOMDocument node with boolean value - php

Question

What is the correct way to extract a boolean value from an XML node? I have tried with this:
<?php
$xml = "<node><code>false</code></node>";
$dom = new DOMDocument();
$dom->loadXML($xml);
$nodeList = $dom->getElementsByTagName('code');
if ($nodeList->length == 1) {
if($nodeList->item(0)->nodeValue){
echo 'VALID';
} else {
echo 'NOT VALID';
}
}
?>
but I get VALID as a result.

Answer 1

nodeValue is going to return a string, so you need to do a string comparison. For example:
if($nodeList->item(0)->nodeValue != 'false'){
echo 'VALID';
} else {
echo 'NOT VALID';
}
You may also consider using filter_var($string, FILTER_VALIDATE_BOOLEAN) to convert the value to boolean (for example it will also convert "1" or "yes" to a boolean), depending on the type of value you'll get in the XML.

Answer 2

Here is no such thing as a 'boolean' value in XML it is all text. But you can use an Xpath expression to validate the value of a specific node and return it as an boolean directly:
$xml = <<<'XML'
<nodes>
<node>
<code>false</code>
</node>
<node>
<code>true</code>
</node>
</nodes>
XML;
$document = new DOMDocument();
$document->loadXml($xml);
$xpath = new DOMXpath($document);
foreach ($xpath->evaluate('//node') as $node) {
var_dump(
$xpath->evaluate('code = "true"', $node)
);
}
Output:
bool(false)
bool(true)
An alternative would be to fetch the value as a string and use filter_var().
foreach ($xpath->evaluate('//node') as $node) {
var_dump(
filter_var($xpath->evaluate('string(code)', $node), FILTER_VALIDATE_BOOLEAN)
);
}

Answer 3

Another solution
( filter_var( $xmlNodeElement->current(), FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE) ) ? echo "Valid" : echo "Not valid";
Current when initialize, show first node element more about follow link