Question

I’m trying to add a new node to an existing XML document.

However, trying to use the push function in a XML::LibXML::NodeList result does not change the document.

Here’s an example:

#!/usr/bin/perl 
use strict;
use XML::LibXML;

my $parser     = XML::LibXML->new();
my $xml_string =
'<example>
    <books>
        <category id="1">
            <book isbn="a" />
            <book isbn="b" />
            <book isbn="c" />
        </category>
        <category id="2"/>
        <category id="3"/>
    </books>
</example>';
my $doc = $parser->parse_string($xml_string);
my $category_nodelist = $doc->findnodes('//category[@id="1"]');

my $book_el = $doc->ownerDocument->createElement('book');
$book_el->setAttribute("isbn", "d");
$category_nodelist->push($book_el);

print $doc->toString(1);

Answer 1

To insert the new node into the document, use

$category_nodelist->[0]->appendChild($book_el);