Question

How can I read the first and only comment in PHP:

<?xml version="1.0" encoding="UTF-8"?>
<!-- read this -->
<root>
</root>

using DOMDOcument object?

$xml = new DOMDocument();

$libxml_error = 'Il file %s non risulta ben formato (%s).';

// Per evitare i warning nel caso di xml non ben formato occorre sopprimere
// gli errori
if (!@$xml -> load($xml_file_path)) $error = sprintf($libxml_error,
    $xml_file_path, libxml_get_last_error()->message);

// Read the fist comment in xml file

Answer 1

What about this:

$xpath = new DOMXPath($xml);
foreach ($xpath->query('//comment()') as $comment) {
    var_dump($comment->textContent);
}

Since you probably only want the first one:

$xpath = new DOMXPath($xml);
$results = $xpath->query('//comment()');
$comment = $results[0];
var_dump($comment);

Source: How to retrieve comments from within an XML Document in PHP