Count view only once in the same browser

app/controllers/asciicasts_controller.rb

@@ -2,7 +2,6 @@ class AsciicastsController < ApplicationController
   PER_PAGE = 15
 
   before_filter :load_resource, :only => [:show, :raw, :edit, :update, :destroy]
-  before_filter :count_view, :only => [:show]
   before_filter :ensure_authenticated!, :only => [:edit, :update, :destroy]
   before_filter :ensure_owner!, :only => [:edit, :update, :destroy]
 
@@ -33,6 +32,7 @@ class AsciicastsController < ApplicationController
       format.html do
         @asciicast = AsciicastDecorator.new(@asciicast)
         @title = @asciicast.title
+        ViewCounter.new(@asciicast, cookies).increment
         respond_with @asciicast
       end
 
@@ -78,12 +78,6 @@ class AsciicastsController < ApplicationController
     @asciicast = Asciicast.find(params[:id])
   end
 
-  def count_view
-    unless request.xhr?
-      Asciicast.increment_counter :views_count, @asciicast.id
-    end
-  end
-
   def ensure_owner!
     if current_user != @asciicast.user
       redirect_to asciicast_path(@asciicast), :alert => "You can't do that."

app/services/view_counter.rb

@@ -0,0 +1,22 @@
+class ViewCounter
+  attr_reader :asciicast, :storage
+
+  def initialize(asciicast, storage)
+    @asciicast = asciicast
+    @storage = storage
+  end
+
+  def increment
+    unless storage[key]
+      Asciicast.increment_counter(:views_count, asciicast.id)
+      asciicast.reload
+      storage[key] = '1'
+    end
+  end
+
+  private
+
+  def key
+    @key ||= :"asciicast_#{asciicast.id}_viewed"
+  end
+end

spec/controllers/asciicasts_controller_spec.rb

@@ -64,9 +64,14 @@ describe AsciicastsController do
     end
 
     context 'for html request' do
+      let(:view_counter) { mock('view_counter') }
+
       before do
         AsciicastDecorator.should_receive(:new).with(asciicast).
           and_return(asciicast)
+        ViewCounter.should_receive(:new).with(asciicast, cookies).
+          and_return(view_counter)
+        view_counter.should_receive(:increment)
 
         get :show, :id => asciicast.id, :format => :html
       end
@@ -82,6 +87,7 @@ describe AsciicastsController do
       before do
         AsciicastJSONDecorator.should_receive(:new).with(asciicast).
           and_return(asciicast)
+        ViewCounter.should_not_receive(:new)
 
         get :show, :id => asciicast.id, :format => :json
       end

spec/services/view_counter_spec.rb

@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+describe ViewCounter do
+  let(:view_counter) { ViewCounter.new(asciicast, storage) }
+  let(:asciicast) { create(:asciicast) }
+  let(:storage) { {} }
+
+  describe '#increment' do
+    context "when called for the first time" do
+      it "increments the views_count" do
+        expect { view_counter.increment }.
+          to change(asciicast, :views_count).by(1)
+      end
+    end
+
+    context "when called for the second time" do
+      before do
+        view_counter.increment
+      end
+
+      it "doesn't increment the views_count" do
+        expect { view_counter.increment }.
+          not_to change(asciicast, :views_count)
+      end
+    end
+  end
+end