LibXML question

Binford has asked for the wisdom of the Perl Monks concerning the following question:

I've read through here, and trying to use some of the exampled, which work perfectly, sems straightforward. So what am I doing wrong? For this XML

<APPLIANCE_LIST_OUTPUT>
  <RESPONSE>
    <DATETIME>2014-06-27T13:38:55Z</DATETIME>
    <APPLIANCE_LIST>
      <APPLIANCE>
        <ID>76297</ID>
        <NAME>st0153</NAME>
        <SOFTWARE_VERSION></SOFTWARE_VERSION>
        <RUNNING_SCAN_COUNT>0</RUNNING_SCAN_COUNT>
        <STATUS>Online</STATUS>
      </APPLIANCE>
      <APPLIANCE>
        <ID>53489</ID>
        <NAME>THD-Mexico</NAME>
        <SOFTWARE_VERSION>2.6</SOFTWARE_VERSION>
        <RUNNING_SCAN_COUNT>0</RUNNING_SCAN_COUNT>
        <STATUS>Online</STATUS>
      </APPLIANCE>
      <APPLIANCE>
        <ID>76079</ID>
        <NAME>QAPLRScanner</NAME>
        <SOFTWARE_VERSION></SOFTWARE_VERSION>
        <RUNNING_SCAN_COUNT>0</RUNNING_SCAN_COUNT>
        <STATUS>Online</STATUS>
      </APPLIANCE>
</APPLIANCE_LIST>
  </RESPONSE>
</APPLIANCE_LIST_OUTPUT>
[download]

Why doesn't this work to output the STATUS node per line?

use XML::LibXML qw();
my $xml = XML::LibXML->load_xml(location => 'output.xml');
for ($xml->findnodes('//appliance_list_output[@status]')) {
    print $_->getAttribute('status') . "\n";
    #print $_->getElementsbyTagName('status') . "\n";
    print $_ . "\n";
}
[download]

Ive' tried various ways to do this, but no matter what irt doesn't seem to enter the "for" loop. BUt if I change the Xpath, it complains, so it seems to READ the XML and have it parsed correctly, but won't examine it? Stumped, thanks in advance...

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Re: LibXML question by AppleFritter (Vicar) on Jun 27, 2014 at 19:59 UTC
Two things. First of all, XML is case-sensitive. `appliance_list_output` is not the same as `APPLIANCE_LIST_OUTPUT`, and the same goes for `status` and `STATUS`. Second (after reading up on XPath), you're not getting results because you're only querying for the `status` attributes of `APPLIANCE_LIST_OUTPUT` nodes, as opposed to `STATUS` nodes descended from them. Try the following: `#!/usr/bin/perl use feature qw/say/; use XML::LibXML qw(); my $xml = XML::LibXML->load_xml(location => 'output.xml'); for ($xml->findnodes('//APPLIANCE_LIST_OUTPUT/descendant::STATUS/text( +)')) { say; }` [download] Here's the output: `Online Online Online` [download] I've also used `text()` to select the text content of the status nodes, BTW. Leaving that out, you'd get "`<STATUS>Online</STATUS>`" for each node, rather than just "`Online`". Does this do what you want? BTW, here's a useful XPath tutorial site.	[reply] [d/l] [select]
Re^2: LibXML question by choroba (Cardinal) on Jun 27, 2014 at 23:10 UTC
Once you use the abbreviation `//` for `/descendant::`, you can use it in both places: `//APPLIANCE_LIST_OUTPUT//STATUS/text()` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]