Convert the whole system to a gem. Lots of repackaging for Railties support

Author: jhubert

Rakefile

@@ -1,5 +1,7 @@
+require 'rubygems'
 require 'rake'
 require 'rake/testtask'
+require 'rake/gempackagetask'
 require 'rake/rdoctask'
 
 desc 'Default: run unit tests.'
@@ -20,4 +22,31 @@ Rake::RDocTask.new(:rdoc) do |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source'
   rdoc.rdoc_files.include('README')
   rdoc.rdoc_files.include('lib/**/*.rb')
+end
+
+PKG_FILES = FileList[
+  '[a-zA-Z]*',
+  'lib/**/*',
+  'rails/**/*',
+  'files/*',
+  'test/**/*'
+]
+ 
+spec = Gem::Specification.new do |s|
+  s.name = "split_tester"
+  s.version = "0.2"
+  s.author = "Jeremy Hubert"
+  s.email = "jhubert@gmail.com"
+  s.homepage = "http://jeremyhubert.com/"
+  s.platform = Gem::Platform::RUBY
+  s.summary = "Provides A/B split testing functionality for Rails"
+  s.files = PKG_FILES.to_a
+  s.require_path = "lib"
+  s.has_rdoc = false
+  s.extra_rdoc_files = ["README"]
+end
+ 
+desc 'Turn this plugin into a gem.'
+Rake::GemPackageTask.new(spec) do |pkg|
+  pkg.gem_spec = spec
 end

init.rb

@@ -1,3 +1 @@
-# Include hook code here
-require 'action_controller'
-require 'split_tester'
+require File.join(File.dirname(__FILE__), "lib", "split_tester")

lib/split_tester.rb

@@ -1,129 +1,54 @@
-require 'action_controller'
+require 'split_tester/railtie'
+require 'split_tester/controller'
+require 'split_tester/translation_helper'
+require 'split_tester/caching'
 
-module ActionController #:nodoc:
+module SplitTester
   class Base
-
-    SPLIT_TESTS = YAML.load_file("#{RAILS_ROOT}/config/split_tests.yml")
-
-    class << self
-      def custom_view_path(name)
-        name == "views" ? "app/views" : "test/split/#{name}/views"
-      end
-      
-      def self.random_test_key
-        split_test_map.sample
+    # Doesn't have access to Rails.root here
+    SPLIT_TESTS = YAML.load_file("config/split_tests.yml")
+
+    def self.setup
+      # Add the split test language files to the load path
+      I18n.load_path += Dir[Rails.root.join('test', 'split', '*', 'locale.{rb,yml}')]
+
+      @@preprocessed_pathsets = begin
+        SPLIT_TESTS.keys.reject { |k| k == 'BASELINE' }.inject({}) do |pathsets, slug|
+          path = custom_view_path(slug)
+          pathsets[path] = ActionView::Base.process_view_paths(path).first
+          pathsets
+        end
       end
-    end
 
-    before_filter :setup_split_testing
-
-    # preprocess some pathsets on boot
-    # doing pathset generation during a request is very costly
-    @@preprocessed_pathsets = begin
-      SPLIT_TESTS.keys.reject { |k| k == 'BASELINE' }.inject({}) do |pathsets, slug|
-        path = ActionController::Base.custom_view_path(slug)
-        pathsets[path] = ActionView::Base.process_view_paths(path).first
-        pathsets
+      @@split_test_map = begin
+        tm = {} # test map
+        SPLIT_TESTS.each { |k, v| tm[k] = v['size'].to_i }
+        tm.keys.zip(tm.values).collect { |v,d| (0...d).collect { v }}.flatten
       end
     end
 
-    @@split_test_map = begin
-      tm = {} # test map
-      SPLIT_TESTS.each { |k, v| tm[k] = v['size'].to_i }
-      tm.keys.zip(tm.values).collect { |v,d| (0...d).collect { v }}.flatten
+    def self.split_test_map
+      @@split_test_map
     end
 
-    cattr_accessor :preprocessed_pathsets, :split_test_map
-
-    # If a split_test_key other than BASELINE exists, add the proper
-    # view path to the load paths used by ActionView
-    def setup_split_testing
-      return unless is_split_test?
-      split_test_path = preprocessed_pathsets[ActionController::Base.custom_view_path(@split_test_key)]
-      prepend_view_path(split_test_path) if split_test_path
-    end
-
-    # Get the existing split_test_key from the session or the cookie.
-    # If there isn't one, or if the one isn't a running test anymore
-    # assign the user a new key and store it. 
-    # Don't assign a key if it is a crawler. (This doesn't feel right)
-    def get_split_test_key
-      return params[:force_test_key] if params[:force_test_key] # just for testing
-      return session[:split_test_key] if session[:split_test_key] && SPLIT_TESTS.has_key?(session[:split_test_key])
-      return session[:split_test_key] = cookies[:split_test_key] if cookies[:split_test_key] && SPLIT_TESTS.has_key?(cookies[:split_test_key])
-      if (request.user_agent =~ /\b(Baidu|Gigabot|Googlebot|libwww-perl|lwp-trivial|msnbot|SiteUptime|Slurp|WordPress|ZIBB|ZyBorg)\b/i)
-        session[:split_test_key] = nil
-      else
-        session[:split_test_key] = ActionController::Base.random_test_key
-        cookies[:split_test_key] = session[:split_test_key]
-      end
-      return session[:split_test_key]
+    def self.preprocessed_pathsets
+      @@preprocessed_pathsets
     end
 
-    def current_split_test_key
-      @split_test_key ||= get_split_test_key
+    def self.custom_view_path(name)
+      name == "views" ? "app/views" : "test/split/#{name}/views"
     end
 
-    def is_split_test?
-      current_split_test_key && current_split_test_key != 'BASELINE'
+    def self.active_test?(key)
+      SPLIT_TESTS.has_key?(key)
     end
 
-    helper_method :is_split_test?, :current_split_test_key
-  end
-end
-
-# Change the namespace for caching if the current request
-# is a split test so that caches don't get mixed together
-module ActionController #:nodoc:
-  module Caching
-    module Fragments
-      def fragment_cache_key(key)
-        namespace = is_split_test? ? "views-split-#{current_split_test_key}" : :views
-        ActiveSupport::Cache.expand_cache_key(key.is_a?(Hash) ? url_for(key).split("://").last : key, namespace)
-      end
+    def self.view_path(key)
+      preprocessed_pathsets[custom_view_path(key)]
     end
-  end
-end
-
-# Overwrite the translate method so that it tries the bucket translation first
-# TODO: There is probably a better way to write this
-module ActionView
-  module Helpers
-    module TranslationHelper
-      def translate(key, options = {})
-        key = scope_key_by_partial(key)
-        if is_split_test?
-          # normalize the parameters so that we can add in 
-          # the current_split_test_key properly
-          scope = options.delete(:scope)
-          keys = I18n.normalize_keys(I18n.locale, key, scope)
-          keys.shift
-          key = keys.join('.')
 
-          # Set the standard key as a default to fall back on automatically
-          if options[:default]
-            options[:default] = [options[:default]] unless options[:default].is_a?(Array)
-            options[:default].unshift(key.to_sym)
-          else
-            options[:default] = [key.to_sym]
-          end
-
-          key = "#{current_split_test_key}.#{key}"
-        end
-        translation = I18n.translate(key, options.merge!(:raise => true))
-        if html_safe_translation_key?(key) && translation.respond_to?(:html_safe)
-          translation.html_safe
-        else
-          translation
-        end
-      rescue I18n::MissingTranslationData => e
-        keys = I18n.normalize_keys(e.locale, e.key, e.options[:scope])
-        content_tag('span', keys.join(', '), :class => 'translation_missing')
-      end
-      alias t translate
+    def self.random_test_key
+      split_test_map.sample
     end
   end
-end
-
-# Add the split test language files to the load path
-I18n.load_path += Dir[Rails.root.join('test', 'split', '*', 'locale.{rb,yml}')]
+end

lib/split_tester/caching.rb

@@ -0,0 +1,14 @@
+# Change the namespace for caching if the current request
+# is a split test so that caches don't get mixed together
+module SplitTester #:nodoc:
+  module Caching
+    def self.included(base)
+      base.class_eval {
+        def fragment_cache_key(key)
+          namespace = is_split_test? ? "views-split-#{current_split_test_key}" : :views
+          ActiveSupport::Cache.expand_cache_key(key.is_a?(Hash) ? url_for(key).split("://").last : key, namespace)
+        end
+      }
+    end
+  end
+end

lib/split_tester/controller.rb

@@ -0,0 +1,47 @@
+module SplitTester #:nodoc:
+  module Controller
+    def self.included(base)
+      base.send(:include, InstanceMethods)
+      base.class_eval {
+        helper_method :is_split_test?, :current_split_test_key
+
+        before_filter :setup_split_testing
+      }
+    end
+
+    module InstanceMethods
+      # If a split_test_key other than BASELINE exists, add the proper
+      # view path to the load paths used by ActionView
+      def setup_split_testing
+        return unless is_split_test?
+        split_test_path = SplitTester::Base.view_path(current_split_test_key)
+        prepend_view_path(split_test_path) if split_test_path
+      end
+
+      # Get the existing split_test_key from the session or the cookie.
+      # If there isn't one, or if the one isn't a running test anymore
+      # assign the user a new key and store it. 
+      # Don't assign a key if it is a crawler. (This doesn't feel right)
+      def get_split_test_key
+        return params[:force_test_key] if params[:force_test_key] && SplitTester::Base.active_test?(params[:force_test_key]) # just for testing
+        return session[:split_test_key] if session[:split_test_key] && SplitTester::Base.active_test?(session[:split_test_key])
+        return session[:split_test_key] = cookies[:split_test_key] if cookies[:split_test_key] && SplitTester::Base.active_test?(cookies[:split_test_key])
+        if (request.user_agent =~ /\b(Baidu|Gigabot|Googlebot|libwww-perl|lwp-trivial|msnbot|SiteUptime|Slurp|WordPress|ZIBB|ZyBorg)\b/i)
+          session[:split_test_key] = nil
+        else
+          session[:split_test_key] = SplitTester::Base.random_test_key
+          cookies[:split_test_key] = session[:split_test_key]
+        end
+        return session[:split_test_key]
+      end
+
+      def current_split_test_key
+        @split_test_key ||= get_split_test_key
+      end
+
+      def is_split_test?
+        current_split_test_key && current_split_test_key != 'BASELINE'
+      end
+    end
+  end
+end

lib/split_tester/railtie.rb

@@ -0,0 +1,22 @@
+require 'split_tester'
+
+module SplitTester
+  if defined? Rails::Railtie
+    require 'rails'
+    class Railtie < Rails::Railtie
+      initializer "split_tester.init" do
+        SplitTester::Railtie.insert
+      end
+    end
+  end
+
+  class Railtie
+    def self.insert
+      ActionController::Base.send(:include, SplitTester::Controller)
+      ActionController::Caching::Fragments.send(:include, SplitTester::Caching)
+      ActionView::Helpers::TranslationHelper.send(:include, SplitTester::TranslationHelper)
+
+      SplitTester::Base.setup
+    end
+  end
+end

lib/split_tester/translation_helper.rb

@@ -0,0 +1,43 @@
+require 'action_view'
+
+module SplitTester
+  module TranslationHelper
+    def self.included(base)
+      # Using class_eval here because base.send(:include, InstanceMethods)
+      # wasn't overwriting the translate method properly. Not sure why.
+      base.class_eval {
+         def translate(key, options = {})
+           key = scope_key_by_partial(key)
+           if is_split_test?
+             # normalize the parameters so that we can add in 
+             # the current_split_test_key properly
+             scope = options.delete(:scope)
+             keys = I18n.normalize_keys(I18n.locale, key, scope)
+             keys.shift
+             key = keys.join('.')
+
+             # Set the standard key as a default to fall back on automatically
+             if options[:default]
+               options[:default] = [options[:default]] unless options[:default].is_a?(Array)
+               options[:default].unshift(key.to_sym)
+             else
+               options[:default] = [key.to_sym]
+             end
+
+             key = "#{current_split_test_key}.#{key}"
+           end
+           translation = I18n.translate(key, options.merge!(:raise => true))
+           if html_safe_translation_key?(key) && translation.respond_to?(:html_safe)
+             translation.html_safe
+           else
+             translation
+           end
+         rescue I18n::MissingTranslationData => e
+           keys = I18n.normalize_keys(e.locale, e.key, e.options[:scope])
+           content_tag('span', keys.join(', '), :class => 'translation_missing')
+         end
+        alias t translate
+      }
+    end
+  end
+end

rails/init.rb

@@ -0,0 +1,3 @@
+# Include hook code here
+require 'split_tester/railtie'
+SplitTester::Railtie.insert