xmlmap

An active record like lib for parsing xml files, with which you can define relations with has_many and conditions, letting you do ::all and #relation_plural_name. Paths can be defined using css paths or xpath.

Install

gem install xmlmap

so lets see an example of it in action. Given an xml file with this structure (actual games.xml sample file is a bit longer):

<?xml version="1.0" encoding="ISO-8859-1" ?>

<data>
	<categories>
		<category>RTS</category>
		<category>Adventure</category>
		<category>FPS</category>
	<categories>

<game>
	<title>Starcraft</title>
 <screenshot>http://fake.com/starcraft1.jpg</screenshot> 
 <screenshot>http://fake.com/starcraft2.jpg</screenshot> 
 <screenshot>http://fake.com/starcraft3.jpg</screenshot> 
 <categories>RTS</categories>
</game>

<game>
	<title>Full throttle</title>
 <screenshot>http://fake.com/fullthrottle1.jpg</screenshot> 
 <screenshot>http://fake.com/fullthrottle2.jpg</screenshot> 
 <screenshot>http://fake.com/fullthrottle3.jpg</screenshot> 
 <categories>Adventure</categories>
</game>

</data>

We can use xmlmap like:

gem 'xmlmap'
require 'xmlmap'

#if a pluralization you need isnt already covered by ActiveSupport, then you'll need to add it like this:
#ActiveSupport::Inflector.inflections do |inflect|
  #inflect.irregular 'rohir', 'rohirrim'
#end

class Game < Xmlmap
set_url './games.xml'
set_path 'data game'
has_many :screenshots, 
	       :conditions => Proc.new { |gm,screen| true } #demo condition filter doing nothing 

  def categories
		self.at('categories').inner_text.strip
  end
end

class Screenshot < Xmlmap
set_url './games.xml'
set_path 'screenshot', :base => :game #so Screenshot.all will look for the combined 'data game screenshot' path

end

class Category < Xmlmap
set_url './games.xml'
set_path 'data categories category'

has_many :games, 
	       :non_descendant_path => [:game],
	       :conditions => Proc.new { |category, game| game.categories.match category.inner_text }           
end

puts 'All game titles and screenshots'
puts ' '

games = Game.all
games.each do |game|
  puts game.at('title').inner_text
  puts '   '+game.screenshots.map(&:inner_text).join(' ')
end

puts ' '
puts 'now lets get the first screenshot for the games in the RTS category'
puts ' '



games = Category.all.detect { |cat| cat.inner_text.strip == 'RTS' }.games

games.each do |game|
  puts game.screenshots.first.inner_text unless game.screenshots.empty?
end

Running the above will print:

All game titles and screenshots
 
Starcraft
   http://fake.com/starcraft1.jpg http://fake.com/starcraft2.jpg http://fake.com/starcraft3.jpg
Full throttle
   http://fake.com/fullthrottle1.jpg http://fake.com/fullthrottle2.jpg http://fake.com/fullthrottle3.jpg
Command and Conquer - Red Alert
   http://fake.com/redalert1.jpg http://fake.com/redalert2.jpg http://fake.com/redalert3.jpg
Day of the tentactle
   http://fake.com/dott1.jpg http://fake.com/dott2.jpg http://fake.com/dott3.jpg
Doom
   http://fake.com/doom1.jpg http://fake.com/doom2.jpg http://fake.com/doom3.jpg
Wolfenstein
   http://fake.com/wolfenstein1.jpg http://fake.com/wolfenstein2.jpg http://fake.com/wolfenstein3.jpg
Call of duty
   http://fake.com/callofduty1.jpg http://fake.com/callofduty2.jpg http://fake.com/callofduty3.jpg
 
now lets get the first screenshot for the games in the RTS category

http://fake.com/starcraft1.jpg
http://fake.com/redalert1.jpg