Implement Endpoints for Songs

Gemfile

@@ -23,5 +23,5 @@ group :test do
 end
 
 gem 'thin'
-gem 'kaminari'
+gem 'will_paginate', '~> 3.0'
 gem 'rabl'

Gemfile.lock

@@ -61,9 +61,6 @@ GEM
       railties (>= 3.0, < 5.0)
       thor (>= 0.14, < 2.0)
     json (1.8.1)
-    kaminari (0.14.1)
-      actionpack (>= 3.0.0)
-      activesupport (>= 3.0.0)
     mail (2.5.4)
       mime-types (~> 1.16)
       treetop (~> 1.4.8)
@@ -134,6 +131,7 @@ GEM
     uglifier (2.3.0)
       execjs (>= 0.3.0)
       json (>= 1.8.0)
+    will_paginate (3.0.5)
 
 PLATFORMS
   ruby
@@ -145,7 +143,6 @@ DEPENDENCIES
   factory_girl
   faker
   jquery-rails
-  kaminari
   pg
   rabl
   rails (= 3.2.15)
@@ -154,3 +151,4 @@ DEPENDENCIES
   shoulda-matchers
   thin
   uglifier (>= 1.0.3)
+  will_paginate (~> 3.0)

app/controllers/songs_controller.rb

@@ -1,10 +1,32 @@
 class SongsController < ApplicationController
   # GET /songs
-  def songs
+  def index
     @songs = Song.paginate(:per_page => 50, :page => params[:page])
 
     respond_to do |format|
       format.html
     end
   end
+
+  # GET /songs/on_sale
+  def on_sale
+    @songs = Song.on_sale.paginate(:per_page => 50, :page => params[:page])
+
+    respond_to do |format|
+      format.html
+    end
+  end
+
+  # POST /songs
+  def create
+    @song = Song.new(title: params[:title], artist: params[:artist], album: params[:album], price_in_cents: params[:price])
+
+    respond_to do |format|
+      if @song.save
+        format.html { render 'songs/song' }
+      else
+        format.html { render json: { errors: @song.errors }, status: :unprocessable_entity }
+      end
+    end
+  end
 end

app/models/bar.rb

@@ -20,6 +20,6 @@ def generate_token
   end
 
   def downcase_name
-    self.name_downcased = self.name.downcase if self.name.present?
+    self.name_downcased = self.name.try(:downcase)
   end
 end

app/views/songs/base.rabl

@@ -0,0 +1 @@
+attributes :id, :title, :artist, :album, :price

app/views/songs/index.html.rabl

@@ -1,5 +1,9 @@
 object false
 
-child (@songs) do
-  extends "songs/song"
+node(:pagination) do
+  pagination_hash(@songs)
+end
+
+child @songs, object_root: false do
+  extends "songs/base"
 end

app/views/songs/on_sale.html.rabl

@@ -0,0 +1,9 @@
+object false
+
+node(:pagination) do
+  pagination_hash(@songs)
+end
+
+child @songs, object_root: false do
+  extends "songs/base"
+end

app/views/songs/song.rabl

@@ -1 +1,3 @@
-attributes :id, :title, :artist, :album, :price
+object @song => ""
+
+extends "songs/base"

spec/controllers/songs_spec.rb

@@ -0,0 +1,102 @@
+require 'spec_helper'
+
+describe 'Songs API' do
+  context "failed request" do
+    subject { JSON.parse(last_response.body)['errors'] }
+
+    context "title, artist, album and price are not provided" do
+      it "responds with an error" do
+        post '/songs'
+        should have_key('title')
+        should have_key('artist')
+        should have_key('album')
+        should have_key('price_in_cents')
+      end
+    end
+
+    context "name is duplicated" do
+      it "respond with an error" do
+        song = FactoryGirl.create(:song)
+        post "/songs", { title: song.title, album: song.album, artist: song.artist, price: 100 }
+        should have_key('title')
+      end
+    end
+  end
+
+  context "successful request" do
+    subject { JSON.parse(last_response.body) }
+
+    it "returns a song record" do
+      post "/songs", { title: "Awesome Song", artist: "Berna", album: "Top Hits", price: 100 }
+      song = Song.last
+
+      subject['id'].should     == song.id
+      subject['title'].should  == song.title
+      subject['artist'].should == song.artist
+      subject['album'].should  == song.album
+      subject['price'].should  == song.price
+    end
+
+    context "returns a list of songs in the server" do
+      before do
+        Song.destroy_all
+        100.times.each do
+          song = FactoryGirl.create :song
+        end
+      end
+
+      let(:url) { "/songs" }
+
+      it "should paginate the first 50 songs" do
+        get url
+        subject.should have_key("pagination")
+        subject["pagination"]["total"].should == 100
+        subject["pagination"]["total_pages"].should == 2
+        subject["pagination"]["current_page"].should == 1
+        subject.should have_key("songs")
+        subject["songs"].count.should eql(50)
+      end
+
+      it "should paginate the second 50 songs" do
+        get url, { page: 2 }
+        subject.should have_key("pagination")
+        subject["pagination"]["total"].should == 100
+        subject["pagination"]["total_pages"].should == 2
+        subject["pagination"]["current_page"].should == 2
+        subject.should have_key("songs")
+        subject["songs"].count.should eql(50)
+      end
+    end
+
+    context "returns a list of songs on sale" do
+      before do
+        Song.destroy_all
+        100.times.each do
+          song = FactoryGirl.create :song, price_in_cents: 100
+        end
+      end
+
+      let(:url) { "/songs/on_sale" }
+
+      it "should paginate the first 50 songs on sale" do
+        get url
+        subject.should have_key("pagination")
+        subject["pagination"]["total"].should == 100
+        subject["pagination"]["total_pages"].should == 2
+        subject["pagination"]["current_page"].should == 1
+        subject.should have_key("songs")
+        subject["songs"].count.should eql(50)
+      end
+
+      it "should paginate the second 50 songs on sale" do
+        get url, { page: 2 }
+        subject.should have_key("pagination")
+        subject["pagination"]["total"].should == 100
+        subject["pagination"]["total_pages"].should == 2
+        subject["pagination"]["current_page"].should == 2
+        subject.should have_key("songs")
+        subject["songs"].count.should eql(50)
+      end
+    end
+  end
+end

spec/models/song_spec.rb

@@ -2,7 +2,7 @@
 
 describe Song do
   before do
-    Bar.delete_all
+    Song.delete_all
   end
 
   it "must have a title" do