How to move a node in XML data using Perl

Question

I've tried several different methods for parsing XML documents. I need to find a node in the document with an xattribute, and then move that node with its children to a different parent node.

I've had some success using XML::LibXML for locating the node and being able to iterate through it's children, but I'm stuck in how to move it to a different parent.

Using $node->cloneNode(1) looks promising but I can't find good examples of its use.

This is the original XML data

<config logdir="/var/log/foo/" debugfile="/tmp/foo.debug">
  <old>
    <server name="sahara" osname="solaris" osversion="2.6">
      <address ip="10.0.0.101">Private</address>
      <address ip="10.0.1.101">Private</address>
    </server>
    <server name="gobi" osname="irix" osversion="6.5">
      <address ip="10.0.0.102">Private</address>
    </server>
    <server name="kalahari" osname="linux" osversion="2.0.34">
      <address ip="10.0.0.103">Private</address>
      <address ip="10.0.1.103">Private</address>
    </server>
  </old>
  <new>
  </new>        
</config>

and this is the result I would like

<config logdir="/var/log/foo/" debugfile="/tmp/foo.debug">
  <old>
    <server name="sahara" osname="solaris" osversion="2.6">
      <address ip="10.0.0.101">Private</address>
      <address ip="10.0.1.101">Private</address>
    </server>
    <server name="gobi" osname="irix" osversion="6.5">
      <address ip="10.0.0.102">Private</address>
    </server>
  </old>
  <new>
    <server name="kalahari" osname="linux" osversion="2.0.34">
      <address ip="10.0.0.103">Private</address>
      <address ip="10.0.1.103">Private</address>
    </server>
  </new>        
</config>

Answer 1

Using XML::LibXML:

use strict;
use warnings;

use XML::LibXML;

my $xml = XML::LibXML->load_xml( IO => \*DATA );

my ($new) = $xml->findnodes('//new');

for my $linux ( $xml->findnodes('//old/server[@osname="linux"]') ) {
    $linux->unbindNode();         # Remove from Parent (done automatically when added elsewhere without cloning)
    $new->addChild($linux);
}

print $xml;

__DATA__
<config logdir="/var/log/foo/" debugfile="/tmp/foo.debug">
    <old>
        <server name="sahara" osname="solaris" osversion="2.6">
            <address ip="10.0.0.101">Private</address>
            <address ip="10.0.1.101">Private</address>
        </server>
        <server name="gobi" osname="irix" osversion="6.5">
            <address ip="10.0.0.102">Private</address>
        </server>
        <server name="kalahari" osname="linux" osversion="2.0.34">
            <address ip="10.0.0.103">Private</address>
            <address ip="10.0.1.103">Private</address>
        </server>
    </old>
    <new>
    </new>      
</config>

Outputs:

<?xml version="1.0"?>
<config logdir="/var/log/foo/" debugfile="/tmp/foo.debug">
    <old>
        <server name="sahara" osname="solaris" osversion="2.6">
            <address ip="10.0.0.101">Private</address>
            <address ip="10.0.1.101">Private</address>
        </server>
        <server name="gobi" osname="irix" osversion="6.5">
            <address ip="10.0.0.102">Private</address>
        </server>

    </old>
    <new>
    <server name="kalahari" osname="linux" osversion="2.0.34">
            <address ip="10.0.0.103">Private</address>
            <address ip="10.0.1.103">Private</address>
        </server></new>      
</config>