use 5.010;
use strict;
use warnings;

use LWP::Simple;
use XML::LibXML;

use constant {
  URL_TEMPLATE => 'http://ax.itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=%s&mt=8',
  APPLE_ITEMS_NS => 'http://www.apple.com/itms/'
};

# Get application ID from command line or use default
my $appid = $ARGV[0] // '321234472';

# Create XML parser object and XPath context
my $libxml = XML::LibXML->new();

my $xpath = XML::LibXML::XPathContext->new();
$xpath->registerNs(itms => APPLE_ITEMS_NS);

# Format URL using template and application ID, load content and parse XML
my $document = $libxml->parse_string(get(sprintf(URL_TEMPLATE, $appid)));

# Extract all <b>-tags from the XML data
my @bs = $xpath->findnodes('//itms:b', $document);

# Print the text contained in the extracted tags
say $_->textContent foreach (@bs);