implemented a basic validator module for lastfm results (improvement necessary)

lib/last_fm/album.rb

@@ -2,7 +2,11 @@ module LastFM
   
   class Album < LastFMRequest
     def self.search query, limit = nil, page = nil
-      album_request "search", "albummatches", query, nil, limit, page
+      album_request "search", "albummatches", query, nil, limit, page do |result|
+        result = LastFM::Validator.validate_mash result
+        result = Hashie::Mash.new({ :album => [] }) if result.blank?
+        update_results "#{current_class_name}_#{__method__}", result
+      end
     end
   
     # return: album name, artist, (top)tags, tracks ( name, duration (in sec) ) mbid (album), release date, image urls ( different sizes )

lib/last_fm/artist.rb

@@ -1,13 +1,20 @@
 module LastFM
   
   class Artist < LastFMRequest
+    
     def self.search query, limit = nil, page = nil
-      artist_request "search", "artistmatches", query, limit, page
+      artist_request "search", "artistmatches", query, limit, page do |result|
+        result = LastFM::Validator.validate_mash result
+        result = Hashie::Mash.new({ :artist => [] }) if result.blank?
+        update_results "#{current_class_name}_#{__method__}", result
+      end
     end
   
     # return: artist name, tags, similar artists, artist bio (summary / long), mbid, image urls ( different sizes )
     def self.getInfo artist
-      artist_request "getInfo", "artist", artist
+      artist_request "getInfo", "artist", artist do |info|
+        LastFM::Validator.validate_mash info, "tag", "image"
+      end
     end
   
     # return: artists ( name, mbid, image urls ( different sizes ) )
@@ -28,14 +35,18 @@ module LastFM
     # return: albums ( name, mbid, album url, image urls ( different sizes ) ) ordered by popularity
     def self.getTopAlbums artist, limit = nil, page = nil
       artist_request "getTopAlbums", "topalbums", artist, limit, page do |albums|
-        if albums["@attr"].total.to_i == 1
-          albums.album = [albums.album] # wrap with Array
-        end
+        albums = LastFM::Validator.validate_mash albums, "album"
+        albums = Hashie::Mash.new({ :album => [] }) if albums.total == "0"
+        update_results "#{current_class_name}_#{__method__}", albums
       end
     end
     
     def self.getImages artist, limit = nil
-      artist_request "getImages", "images", artist, limit
+      artist_request "getImages", "images", artist, limit do |images|
+        images = LastFM::Validator.validate_mash images, "image"
+        images = Hashie::Mash.new({ :image => [] }) if images.total == "0"
+        update_results "#{current_class_name}_#{__method__}", images
+      end
     end
   
   end

lib/last_fm/chart.rb

@@ -1,11 +1,18 @@
 module LastFM
+
   class Chart < LastFMRequest
     def self.getTopArtists limit = nil, page = nil
-      chart_request "getTopArtists", "artists", limit, page
+      chart_request "getTopArtists", "artists", limit, page do |artists|
+        LastFM::Validator.validate_mash artists, "image"
+        update_results "#{current_class_name}_#{__method__}", artists
+      end
     end
-    
+
     def self.getTopTracks limit = nil, page = nil
-      chart_request "getTopTracks", "tracks", limit, page
+      chart_request "getTopTracks", "tracks", limit, page do |tracks|
+        LastFM::Validator.validate_mash tracks
+        update_results "#{current_class_name}_#{__method__}", tracks
+      end
     end
   end
 

lib/last_fm/last_fm_request.rb

@@ -4,12 +4,12 @@ require 'hashie'
 module LastFM
 
   class LastFMRequest
-    
+
     @@base_uri = 'http://ws.audioscrobbler.com/2.0/'
     @@default_params = { :format => 'json', :autocorrect => '1' }
     @@hydra = Typhoeus::Hydra.new
     @@results = {}
-    
+
     def self.api_key=(key)
       @@api_key = key
       @@default_params[:api_key] = key
@@ -18,15 +18,15 @@ module LastFM
     def self.base_uri
       return @@base_uri
     end
-    
+
     def self.default_params
       return @@default_params
     end
-    
+
     def self.results
       return @@results
     end
-  
+
     def self.run_queue!
       puts "<< ----------- started request queue ---------"
       @@hydra.run
@@ -34,52 +34,59 @@ module LastFM
     end
 
     def self.artist_request method, node, q, limit = nil, page = nil, &block
-      klass_name = self.name.split('::').last.downcase!
-      request_params = default_params.merge( :method => "#{klass_name}.#{method.to_s}", :artist => q, :limit => limit, :page => page )
-      create_and_queue_request klass_name, method, node, block, request_params
+      request_params = default_params.merge( :method => "#{current_class_name}.#{method.to_s}", :artist => q, :limit => limit, :page => page )
+      create_and_queue_request method, node, block, request_params
     end
 
     def self.album_request method, node, q, artist = nil, limit = nil, page = nil, &block
-      klass_name = self.name.split('::').last.downcase!
-      request_params = default_params.merge( :method => "#{klass_name}.#{method.to_s}", :album => q, :artist => artist, :limit => limit, :page => page )
-      create_and_queue_request klass_name, method, node, block, request_params
+      request_params = default_params.merge( :method => "#{current_class_name}.#{method.to_s}", :album => q, :artist => artist, :limit => limit, :page => page )
+      create_and_queue_request method, node, block, request_params
     end
 
     def self.track_request method, node, q, artist = nil, limit = nil, page = nil, &block
-      klass_name = self.name.split('::').last.downcase!
-      request_params = default_params.merge( :method => "#{klass_name}.#{method.to_s}", :track => q, :artist => artist, :limit => limit, :page => page )
-      create_and_queue_request klass_name, method, node, block, request_params
+      request_params = default_params.merge( :method => "#{current_class_name}.#{method.to_s}", :track => q, :artist => artist, :limit => limit, :page => page )
+      create_and_queue_request method, node, block, request_params
     end
-    
+
     def self.chart_request method, node, limit = nil, page = nil, &block
-      klass_name = self.name.split('::').last.downcase!
-      request_params = default_params.merge( :method => "#{klass_name}.#{method.to_s}", :limit => limit, :page => page )
-      create_and_queue_request klass_name, method, node, block, request_params
+      request_params = default_params.merge( :method => "#{current_class_name}.#{method.to_s}", :limit => limit, :page => page )
+      create_and_queue_request method, node, block, request_params
+    end
+
+    protected
+
+    def self.update_results key, hash
+      @@results[(key.to_sym)].update hash
+    end
+
+    def self.current_class_name
+      self.name.split('::').last.downcase!
     end
 
     private
-    
-    def self.create_and_queue_request klass_name, method, node, block, request_params
+
+    def self.create_and_queue_request method, node, block, request_params
       request = Typhoeus::Request.new(base_uri, :params => request_params)
-      handle_response request, klass_name, method, node, block
+      handle_response request, method, node, block
       
-      puts ">> ---- '#{klass_name}.#{method.to_s}' request is queued ----" if @@hydra.queue request
-      @@results[(klass_name + "_" + method).to_sym] = Hashie::Mash.new
+      puts ">> ---- '#{current_class_name}.#{method.to_s}' request is queued ----" if @@hydra.queue request
+      @@results[(current_class_name + "_" + method).to_sym] = Hashie::Mash.new
     end
-    
-    def self.handle_response request, klass_name, method, node, block
+
+    def self.handle_response request, method, node, block
       request.on_complete do |response|
         if response.success?
-          puts "<< ---- '#{klass_name}.#{method.to_s}' -- TIME: #{response.time.to_s} ----"
+          puts "<< ---- '#{current_class_name}.#{method.to_s}' -- TIME: #{response.time.to_s} ----"
           
-          hash = Hashie::Mash.new(JSON.parse(response.body)) 
+          hash = Hashie::Mash.new(JSON.parse(response.body))
+          puts hash
           hash = method.to_s == "search" ? hash.results.send(node.to_sym) : hash.send(node.to_sym)
           
-          @@results[(klass_name + "_" + method).to_sym].update hash
+          update_results "#{current_class_name}_#{method}", hash unless hash.blank?
           
-          block.call(@@results[(klass_name + "_" + method).to_sym]) unless block.nil?
+          block.call(@@results[("#{current_class_name}_#{method}").to_sym]) unless block.nil?
         elsif response.timed_out?
-          puts ">> -- '#{klass_name}.#{method.to_s}' -- TIMED OUT -- <<"
+          puts ">> -- '#{current_class_name}.#{method.to_s}' -- TIMED OUT -- <<"
         end
       end
     end

lib/last_fm/track.rb

@@ -2,7 +2,11 @@ module LastFM
   
   class Track < LastFMRequest
     def self.search query, limit = nil, page = nil
-      track_request "search", "trackmatches", query, nil, limit, page
+      track_request "search", "trackmatches", query, nil, limit, page do |result|
+        result = LastFM::Validator.validate_mash result
+        result = Hashie::Mash.new({ :track => [] }) if result.blank?
+        update_results "#{current_class_name}_#{__method__}", result
+      end
     end
   
     # return: track name, id, (top)tags, artist, duration (in msec), album ( artist, title, image urls ( different sizes) ), mbid

lib/last_fm/validator.rb

@@ -0,0 +1,28 @@
+module LastFM
+  
+  class Validator
+    
+    def self.validate_mash mash, *args
+      args.flatten!
+      
+      return [] if mash.blank?
+      
+      mash.each do |key, value|
+        if args.include? key.to_s || value.is_a?(Array)
+          mash[key] = Array.wrap value
+          mash[key].map do |mashie|
+            validate_mash mashie, args
+          end
+        elsif value.is_a? Hashie::Mash
+          mash[key] = validate_mash mash[key], args
+        end
+        mash[key] = "" if value.blank? && value.is_a?(String)
+        mash[key] = [] if value.blank? && value.is_a?(Array)
+      end
+      
+      return mash
+    end
+
+  end
+  
+end