diff --git a/lib/models/music_brainz.rb b/lib/models/music_brainz.rb
index 74ac0b6..9f5fb4c 100644
--- a/lib/models/music_brainz.rb
+++ b/lib/models/music_brainz.rb
@@ -13,7 +13,7 @@ module MusicBrainz
     url = WEB_SERVICE_URL + resourse.to_s.gsub('_', '-') + '/' + (params[:id].to_s || '')
     params.delete(:id) unless params[:id].nil?
     url << '?' + params.map{ |k, v|
-      k.to_s + '=' + (v.is_a?(Array) ? v.map{ |_| _.to_s.gsub('_', '-') }.join(',') : v.to_s)
+      k.to_s.gsub('_', '-') + '=' + (v.is_a?(Array) ? v.map{ |_| _.to_s.gsub('_', '-') }.join(',') : v.to_s)
     }.join('&') unless params.empty?
     self.get_contents url
   end
diff --git a/lib/models/music_brainz/artist.rb b/lib/models/music_brainz/artist.rb
index fa1ef67..e13446a 100644
--- a/lib/models/music_brainz/artist.rb
+++ b/lib/models/music_brainz/artist.rb
@@ -49,8 +49,8 @@ module MusicBrainz
           :name => a.first_element_child.text,
           :weight => 0,
           :desc => self.safe_get_value(a, 'disambiguation'),
-          :type => self.safe_get_attr(a, 'type'),
-          :mbid => self.safe_get_attr(a, 'id')
+          :type => self.safe_get_attr(a, nil, 'type'),
+          :mbid => self.safe_get_attr(a, nil, 'id')
         }
         aliases = a.css('alias-list > alias').map{ |item| item.text }
         if aliases.include? name
diff --git a/lib/models/music_brainz/base.rb b/lib/models/music_brainz/base.rb
index 1bfeb4d..b7e10bf 100644
--- a/lib/models/music_brainz/base.rb
+++ b/lib/models/music_brainz/base.rb
@@ -1,7 +1,8 @@
 module MusicBrainz
   class Base
     def self.safe_get_attr xml, path, name
-      xml.css(path).first.attr(name) unless xml.css(path).empty? or xml.css(path).first.attr(name).nil?
+      node = path.nil? ? xml : (xml.css(path).first unless xml.css(path).empty?)
+      node.attr(name) unless node.nil? or node.attr(name).nil?
     end
     
     def self.safe_get_value xml, path
diff --git a/lib/models/music_brainz/release.rb b/lib/models/music_brainz/release.rb
index 6b6a500..344cdbf 100644
--- a/lib/models/music_brainz/release.rb
+++ b/lib/models/music_brainz/release.rb
@@ -1,12 +1,12 @@
 module MusicBrainz
-  class Release
+  class Release < MusicBrainz::Base
     attr_accessor :id, :title, :status, :date, :country
     @tracks
   
     def tracks
       if @tracks.nil? and not self.id.nil?
         @tracks = []
-        Nokogiri::XML(MusicBrainz.load('http://musicbrainz.org/ws/2/release/' + self.id + '?inc=recordings&limit=100')).css('medium-list > medium > track-list > track').each do |r|
+        Nokogiri::XML(MusicBrainz.load(:release, :id => self.id, :inc => [:recordings], :limit => 100)).css('medium-list > medium > track-list > track').each do |r|
           @tracks << MusicBrainz::Track.parse_xml(r)
         end
       end
@@ -14,15 +14,15 @@ module MusicBrainz
     end
   
     def self.find mbid
-      xml = Nokogiri::XML(MusicBrainz.load('http://musicbrainz.org/ws/2/release/' + mbid)).css('release').first
+      xml = Nokogiri::XML(MusicBrainz.load(:release, :id => mbid)).css('release').first
       self.parse_xml(xml) unless xml.nil?
     end
   
     def self.parse_xml xml
       @release = MusicBrainz::Release.new
-      @release.id = xml.attr('id')
-      @release.title = xml.css('title').text unless xml.css('title').empty?
-      @release.status = xml.css('status').text unless xml.css('status').empty?
+      @release.id = self.safe_get_attr(xml, nil, 'id')
+      @release.title = self.safe_get_value(xml, 'title')
+      @release.status = self.safe_get_value(xml, 'status')
       date = xml.css('date').empty? ? '2030-12-31' : xml.css('date').text
       if date.length == 0
         date = '2030-12-31'
@@ -33,7 +33,7 @@ module MusicBrainz
       end
       date = date.split('-')
       @release.date = Time.utc(date[0], date[1], date[2])
-      @release.country = xml.css('country').text unless xml.css('country').empty?
+      @release.country = self.safe_get_value(xml, 'country')
       @release
     end
   end
diff --git a/lib/models/music_brainz/release_group.rb b/lib/models/music_brainz/release_group.rb
index 167d237..5e1cff4 100644
--- a/lib/models/music_brainz/release_group.rb
+++ b/lib/models/music_brainz/release_group.rb
@@ -1,12 +1,12 @@
 module MusicBrainz
-  class ReleaseGroup
+  class ReleaseGroup < MusicBrainz::Base
     attr_accessor :id, :type, :title, :disambiguation, :first_release_date
     @releases
   
     def releases
       if @releases.nil? and not self.id.nil?
         @releases = []
-        Nokogiri::XML(MusicBrainz.load('http://musicbrainz.org/ws/2/release/?release-group=' + self.id + '&limit=100')).css('release').each do |r|
+        Nokogiri::XML(MusicBrainz.load(:release, :release_group => self.id, :inc => [:media], :limit => 100)).css('release').each do |r|
           @releases << MusicBrainz::Release.parse_xml(r)
         end
       end
@@ -14,16 +14,16 @@ module MusicBrainz
     end
   
     def self.find mbid
-      xml = Nokogiri::XML(MusicBrainz.load('http://musicbrainz.org/ws/2/release-group/' + mbid)).css('release-group').first
+      xml = Nokogiri::XML(MusicBrainz.load(:release_group, :id => mbid)).css('release-group').first
       self.parse_xml(xml) unless xml.nil?
     end
   
     def self.parse_xml xml
       @release_group = MusicBrainz::ReleaseGroup.new
-      @release_group.id = xml.attr('id')
-      @release_group.type = xml.attr('type')
-      @release_group.title = xml.css('title').text
-      @release_group.disambiguation = xml.css('disambiguation').empty? ? '' : xml.css('disambiguation').text
+      @release_group.id = self.safe_get_attr(xml, nil, 'id')
+      @release_group.type = self.safe_get_attr(xml, nil, 'type')
+      @release_group.title = self.safe_get_value(xml, 'title')
+      @release_group.disambiguation = self.safe_get_value(xml, 'disambiguation')
       date = xml.css('first-release-date').empty? ? '2030-12-31' : xml.css('first-release-date').text
       if date.length == 0
         date = '2030-12-31'
diff --git a/lib/models/music_brainz/track.rb b/lib/models/music_brainz/track.rb
index eabcbd7..44957d6 100644
--- a/lib/models/music_brainz/track.rb
+++ b/lib/models/music_brainz/track.rb
@@ -1,19 +1,19 @@
 module MusicBrainz
-  class Track
+  class Track < MusicBrainz::Base
     attr_accessor :position, :recording_id, :title, :length
   
     def self.find mbid
-      xml = Nokogiri::XML(MusicBrainz.load('http://musicbrainz.org/ws/2/recording/' + mbid + '?limit=100'))
+      xml = Nokogiri::XML(MusicBrainz.load(:recording, :id => mbid))
       self.parse_xml(xml) unless xml.nil?
     end
   
     def self.parse_xml xml
       @track = MusicBrainz::Track.new
-      @track.position = xml.css('position').text.to_i unless xml.css('position').empty?
-      @track.recording_id = xml.css('recording').attr('id').value unless xml.css('recording').empty?
-      @track.title = xml.css('recording > title').text unless xml.css('recording > title').empty?
-      @track.length = xml.css('length').first.text.to_i unless xml.css('length').empty?
-      @track.length = xml.css('recording > length').first.text.to_i unless xml.css('recording > length').empty?
+      @track.position = self.safe_get_value(xml, 'position').to_i
+      @track.recording_id = self.safe_get_attr(xml, 'recording', 'id')
+      @track.title = self.safe_get_value(xml, 'recording > title')
+      @track.length = self.safe_get_value(xml, 'length').to_i
+      @track.length = self.safe_get_value(xml, 'recording > length').to_i
       @track
     end
   end