care to illustrate use of xml cpan modules?

[BigBear]

how do I access xml attribute details using XML::Simple and/or XML::Mini::Document or XML::LibXML ?

I am trying to understand and compare 4 ways in which I could use perl cpan xml modules to extract some info from a bunch of given XML files.

I have written some proof of concept code using XML::XPath and am left wondering how this "simple" task would be solved by using on of the other XML modules? I am a beginner in some ways and learn best by observing a problem and then copying that sample and modyfying it to my needs.

my perl XML::XPath code
#!/usr/bin/perl 
#file: show-barcodes-with-XML-XPath.pl
#!/usr/bin/perl

use XML::XPath; 
 
my $file = "00000002.TIF.xml"; 
my $xp = XML::XPath->new(filename => $file); 
my $barcode_code39 = $xp->find('/barcodes/source/index/symbol[@type="C
+ODE-39"]/data');
my $barcode_qrcode = $xp->find('/barcodes/source/index/symbol[@type="Q
+R-Code"]/data');

$barcode_code39 = substr($barcode_code39, 0, 10);

print ("Code 39: ", $barcode_code39, "\n");
print ("QR-Code: ", $barcode_qrcode, "\n");

#print ("processed: " . $file . "\n");



#file: 00000002.TIF.xml
<barcodes xmlns='http://zbar.sourceforge.net/2008/barcode'>
<source href='00000002.TIF'>
<index num='0'>
<symbol type='QR-Code' quality='1'><data><![CDATA[0037000249]]></data>
+</symbol>
<symbol type='CODE-39' quality='102'><data><![CDATA[0037000249P]]></da
+ta></symbol>
</index>
</source>
</barcodes>

How would I employ XML::Simple to do the "same" thing ?

And how would I write the same thing using XML::Mini::Document ?

And lastly how would I write the same thing using XML::LibXML ?

Thanks for any insights into how this would be done using one of the above

[tobyink]

With XML::LibXML it's pretty similar. The biggest change is that libxml sticks rigidly to the XPath spec and forces you to use a namespace prefix for matching element names in the 'http://zbar.sourceforge.net/2008/barcode' namespace.

use XML::LibXML;

my $file = '00000002.TIF.xml';
my $xp = XML::LibXML::XPathContext->new(
    XML::LibXML->load_xml(location => $file),
);
$xp->registerNs(b => 'http://zbar.sourceforge.net/2008/barcode');

my $barcode_code39 = $xp->find('/b:barcodes/b:source/b:index/b:symbol[
+@type="CODE-39"]/b:data');
my $barcode_qrcode = $xp->find('/b:barcodes/b:source/b:index/b:symbol[
+@type="QR-Code"]/b:data');

$barcode_code39 = substr($barcode_code39, 0, 10);

print ("Code 39: ", $barcode_code39, "\n");
print ("QR-Code: ", $barcode_qrcode, "\n");

[mirod]

If you want comparisons of various XML modules, have a look at the Ways to Rome series. It presents the same task, done with many different modules.

[Mr. Muskrat]

This is how I would do it with XML::Simple.

#!/usr/bin/perl
use strict;
use warnings;

use XML::Simple;

my $file = '00000002.TIF.xml';
my $xml = XMLin(
    $file,
    KeyAttr => { symbol => 'type' },
);

my %barcode = (
    code39 => substr( $xml->{source}{index}{symbol}{'CODE-39'}{data}, 
+0, 10 ),
    qrcode => $xml->{source}{index}{symbol}{'QR-Code'}{data},
);

print "Code 39: $barcode{code39}\n";
print "QR_Code: $barcode{qrcode}\n";

[grantm]

This node compares examples of using XML::Simple and XML::LibXML. I strongly recommend the latter and definitely don't recommend XML::XPath.

[Anonymous Monk]

Well, each one of the candidates comes with lots of examples, look in the MANIFEST