How to append XML string into a DOMDocument object? - php

Question

Creating the DOMDocument object:
$getToken = '<getToken>...</getToken>';
$getToken_objeto = new DOMDocument("1.0", "UTF-8");
$getToken_objeto -> loadXML($getToken);
Trying to append a XML string (Signature) into the DOMDocument created above:
$Signature = '<Signature>...</Signature>';
$Signature_objeto = new DOMDocument("1.0", "UTF-8");
$Signature_objeto -> loadXML($Signature);
$Signature_nodeList = $Signature_objeto -> getElementsByTagName("Signature");
$Signature_node = $Signature_nodeList -> item(0);
$getToken_objeto -> importNode($Signature_node, true);
$getToken_objeto -> appendChild($Signature_node);
I get 2 errors:
Fatal error: Uncaught exception 'DOMException' with message 'Wrong Document Error' in C:...
DOMException: Wrong Document Error in C:...
Seems simple to resolve but im quite unexperienced using the PHP DOM extension.
Thanks in advance.

Answer 1

You're trying to append the original node - not the imported one.
$Signature_node = $getToken_objeto->importNode(
$Signature_nodeList->item(0), true
);
You're trying to append the node to the document, but an XML document can only have a single document element and it already has one. You can append it to the document element:
$getToken_objeto->documentElement->appendChild($Signature_node);
But PHP can load XML fragments directly into a DOMDocumentFragment.
$xml = '<getToken>...</getToken>';
$fragmentXml = '<Signature>...</Signature>';
$dom = new DOMDocument();
$dom->loadXML($xml);
$xpath = new DOMXpath($dom);
$fragment = $dom->createDocumentFragment();
$fragment->appendXml($fragmentXml);
$xpath
->evaluate('//getToken')
->item(0)
->appendChild($fragment);
echo $dom->saveXml();