Validate XML using a custom DTD in PHP

Question

Is there a way (without installing any libraries) of validating XML using a custom DTD in PHP?

Answer 1

If you have the dtd in a string, you can validate against it by using a data wrapper for the dtd:

$xml = '
        
        
            Tove
            Jani
            Reminder
            Don\'t forget me this weekend!
        ';

$dtd = '
        
        
        
        ';


$root = 'note';

$systemId = 'data://text/plain;base64,'.base64_encode($dtd);

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

$creator = new DOMImplementation;
$doctype = $creator->createDocumentType($root, null, $systemId);
$new = $creator->createDocument(null, null, $doctype);
$new->encoding = "utf-8";

$oldNode = $old->getElementsByTagName($root)->item(0);
$newNode = $new->importNode($oldNode, true);
$new->appendChild($newNode);

if (@$new->validate()) {
    echo "Valid";
} else {
    echo "Not valid";
}