Refactor controllers

app/controllers/api/playlists_controller.rb

@@ -1,11 +1,12 @@
 module API
   class PlaylistsController < ApplicationController
+    before_action :set_playlist, only: :show
+
     def index
       @playlists = Playlist.all
     end
 
     def show
-      @playlist = Playlist.find(params[:id])
     end
 
     def create
@@ -16,6 +17,10 @@ module API
 
     private
 
+    def set_playlist
+      @playlist = Playlist.find(params[:id])
+    end
+
     def playlist_params
       params.require(:playlist).permit :name
     end

app/controllers/api/sounds_controller.rb

@@ -1,9 +1,16 @@
 module API
   class SoundsController < ApplicationController
-    # FIXME: add some tests!
+    before_action :set_sound, only: :show
+
     def show
-      sound = Sound.find(params[:id])
       send_file sound.path, type: sound.mime_type
     end
+
+
+    private
+
+    def set_sound
+      @sound = Sound.find(params[:id])
+    end
   end
 end

app/controllers/api/tracks_controller.rb

@@ -1,10 +1,18 @@
 module API
   class TracksController < ApplicationController
+    before_action :set_track, only: :show
+
     def index
       @tracks = Track.all
     end
 
     def show
+    end
+
+
+    private
+
+    def set_track
       @track = Track.find(params[:id])
     end
   end