Change an XML attribute value using XML::Twig

Question

I want to change an XML attribute value using XML::Twig. I can do this by using XML::LibXML like this

       my $doc = XML::LibXML->new->parsefile();
       my $xpath = '/model/@name';
       my ($attr) = $doc->findnodes($xpath);    
       $attr->setValue('dfdsa');

But I have to used XML::Twig because of some constraints

input

<model name="XXXX" oid="i">
  <system oid="1" uri="/gaia" listing="NO">
    <schema desc="HTTP Sever schema" enab="YES" name="HTTP" oid="1" prio="5">
    </schema>
  </system>
</model>

output

<model name="dfdsa" oid="i">
  <system oid="1" uri="/gaia" listing="NO">
    <schema desc="HTTP Sever schema" enab="YES" name="HTTP" oid="1" prio="5">
    </schema>
  </system>
</model>

I tried this code but it's not modifying the content

my $doc = XML::Twig->new->parsefile('pattern.xml');
my $xpath = '/model';
my ($attr) = $doc->findnodes($xpath);
$attr->set_att(name => 'dfdsa');

What did you try? Setting the value of the attribute is done with `$elt->set_att( name => 'dfdsa')` — mirod, Aug 13 '12 at 06:05
Hello Minard, I tried below but its not modifing the content :( my $doc = XML::Twig->new->parsefile('pattern.xml'); my $xpath = '/model'; my ($attr) = $doc->findnodes($xpath); $attr->set_att( name => 'dfdsa'); — user1575765, Aug 13 '12 at 06:37
Even i tried with below Bud didn't worked XML::Twig->new( twig_handlers => { 'model' => sub {$_->set_att( name => 'dfdsa')} } ,)->parsefile( 'pattern.xml'); — user1575765, Aug 13 '12 at 07:05
it should work. Please post a proper test case, with code we can run, including the data in a _DATA__ section if possible. Without it all we can do is guess. This will also avoid your XML to be invalid. I am not sure how to fix you spelling and your messing up people's name though (Bud is a beer, minard is not my name) ;--( — mirod, Aug 13 '12 at 07:12
your code works... if at some point you output the XML::Twig object. it doesn't magically update the file on disk. You need to have a `$doc->print`, or `$doc->print_to_file(...)` at the end of the code — mirod, Aug 13 '12 at 08:44
@mirod : Sorry sorry I was confused!!!. Thanks alot for your suggestion — user1575765, Aug 13 '12 at 11:25

score 1 · Answer 1 · answered Aug 13 '12 at 07:07

I am very disappointed that you seem to have done almost nothing to try to solve this problem yourself. Even the XML in your question was malformed and I had to fix it.

This program will do what you want

use strict;
use warnings;

use XML::Twig;

my $twig = XML::Twig->new;
$twig->parsefile('pattern.xml');

my ($model) = $twig->findnodes('/model[@name]');
$model->set_att(name => 'dfdsa');

$twig->print(pretty_print => 'indented');

output

<model name="dfdsa" oid="i">
  <system listing="NO" oid="1" uri="/gaia">
    <schema desc="HTTP Sever schema" enab="YES" name="HTTP" oid="1" prio="5"></schema>
  </system>
</model>

Change an XML attribute value using XML::Twig

1 Answers1