Perl Language XML Parsing Consuming XML with XML::Rabbit

Example

With XML::Rabbit it is possible to consume XML files easily. You define in a declarative way and with an XPath syntax what you are looking for in the XML and XML::Rabbit will return objects according to the given definition.

Definition:

package Bookstore;
use XML::Rabbit::Root;
has_xpath_object_list books => './book' => 'Bookstore::Book';
finalize_class();
  
package Bookstore::Book;
use XML::Rabbit;
has_xpath_value bookid => './@id';
has_xpath_value author => './author';
has_xpath_value title => './title';
has_xpath_value genre => './genre';
has_xpath_value price => './price';
has_xpath_value publish_date => './publish_date';
has_xpath_value description => './description';
has_xpath_object purchase_data => './purchase_data' => 'Bookstore::Purchase';
finalize_class();

package Bookstore::Purchase;
use XML::Rabbit;
has_xpath_value price => './price';
has_xpath_value date => './date';
finalize_class();

XML Consumption:

use strict;
use warnings;
use utf8;
  
package Library;
use feature qw(say);
use Carp;
use autodie;
 
say "Showing data information";
my $bookstore = Bookstore->new( file => './sample.xml' );
 
foreach my $book( @{$bookstore->books} ) {
    say "ID: " . $book->bookid;
    say "Title: " . $book->title;
    say "Author: " . $book->author, "\n";
}

Notes:

Please be careful with the following:

1. The first class has to be XML::Rabbit::Root. It will place you inside the main tag of the XML document. In our case it will place us inside <catalog>

2. Nested classes which are optional. Those classes need to be accessed via a try/catch (or eval / $@ check) block. Optional fields will simply return null. For example, for purchase_data the loop would be:

foreach my $book( @{$bookstore->books} ) {
    say "ID: " . $book->bookid;
    say "Title: " . $book->title;
    say "Author: " . $book->author;
    try {
        say "Purchase price: ". $book->purchase_data->price, "\n";
    } catch {
        say "No purchase price available\n";
    }
}

sample.xml

<?xml version="1.0"?>
<catalog>
   <book id="bk101">
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
      <publish_date>2000-10-01</publish_date>
      <description>An in-depth look at creating applications 
      with XML.</description>
   </book>
   <book id="bk102">
      <author>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2000-12-16</publish_date>
      <description>A former architect battles corporate zombies, 
      an evil sorceress, and her own childhood to become queen 
      of the world.</description>
   </book>
   <book id="bk103">
      <author>Corets, Eva</author>
      <title>Maeve Ascendant</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2000-11-17</publish_date>
      <description>After the collapse of a nanotechnology 
      society in England, the young survivors lay the 
      foundation for a new society.</description>
   </book>
   <book id="bk104">
      <author>Corets, Eva</author>
      <title>Oberon's Legacy</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2001-03-10</publish_date>
      <description>In post-apocalypse England, the mysterious 
      agent known only as Oberon helps to create a new life 
      for the inhabitants of London. Sequel to Maeve 
      Ascendant.</description>
      <purchase_data>
        <date>2001-12-21</date>
        <price>20</price>
      </purchase_data>
   </book>
</catalog>