Do not depend on railties, only load railtie if Rails is defined

lib/rails-observers.rb

@@ -1,34 +1,2 @@
-require 'rails'
 require 'rails/observers/version'
-
-module Rails
-  module Observers
-    class Railtie < ::Rails::Railtie
-      initializer "active_record.observer", :before => "active_record.set_configs" do |app|
-        ActiveSupport.on_load(:active_record) do
-          require "rails/observers/activerecord/active_record"
-
-          if observers = app.config.respond_to?(:active_record) && app.config.active_record.delete(:observers)
-            send :observers=, observers
-          end
-        end
-      end
-
-      initializer "action_controller.caching.sweepers" do
-        ActiveSupport.on_load(:action_controller) do
-          require "rails/observers/action_controller/caching"
-        end
-      end
-
-      config.after_initialize do |app|
-        ActiveSupport.on_load(:active_record) do
-          ActiveRecord::Base.instantiate_observers
-
-          ActionDispatch::Reloader.to_prepare do
-            ActiveRecord::Base.instantiate_observers
-          end
-        end
-      end
-    end
-  end
-end
+require 'rails/observers/railtie' if defined? Rails

lib/rails/observers/railtie.rb

@@ -0,0 +1,33 @@
+require 'rails/railtie'
+
+module Rails
+  module Observers
+    class Railtie < ::Rails::Railtie
+      initializer "active_record.observer", :before => "active_record.set_configs" do |app|
+        ActiveSupport.on_load(:active_record) do
+          require "rails/observers/activerecord/active_record"
+
+          if observers = app.config.respond_to?(:active_record) && app.config.active_record.delete(:observers)
+            send :observers=, observers
+          end
+        end
+      end
+
+      initializer "action_controller.caching.sweepers" do
+        ActiveSupport.on_load(:action_controller) do
+          require "rails/observers/action_controller/caching"
+        end
+      end
+
+      config.after_initialize do |app|
+        ActiveSupport.on_load(:active_record) do
+          ActiveRecord::Base.instantiate_observers
+
+          ActionDispatch::Reloader.to_prepare do
+            ActiveRecord::Base.instantiate_observers
+          end
+        end
+      end
+    end
+  end
+end

rails-observers.gemspec

@@ -10,14 +10,13 @@ Gem::Specification.new do |s|
   s.homepage    = "https://github.com/rails/rails-observers"
   s.version     = Rails::Observers::VERSION
 
-  s.files         = [".gitignore",".travis.yml","Gemfile","LICENSE","README.md","Rakefile","lib/generators/active_record/observer/observer_generator.rb","lib/generators/active_record/observer/templates/observer.rb","lib/generators/rails/observer/USAGE","lib/generators/rails/observer/observer_generator.rb","lib/generators/test_unit/observer/observer_generator.rb","lib/generators/test_unit/observer/templates/unit_test.rb","lib/rails-observers.rb","lib/rails/observers/action_controller/caching.rb","lib/rails/observers/action_controller/caching/sweeping.rb","lib/rails/observers/active_model/active_model.rb","lib/rails/observers/active_model/observer_array.rb","lib/rails/observers/active_model/observing.rb","lib/rails/observers/activerecord/active_record.rb","lib/rails/observers/activerecord/base.rb","lib/rails/observers/activerecord/observer.rb","lib/rails/observers/version.rb","rails-observers.gemspec","rails-observers.gemspec.erb","test/configuration_test.rb","test/console_test.rb","test/fixtures/developers.yml","test/fixtures/minimalistics.yml","test/fixtures/topics.yml","test/generators/generators_test_helper.rb","test/generators/namespaced_generators_test.rb","test/generators/observer_generator_test.rb","test/helper.rb","test/isolation/abstract_unit.rb","test/lifecycle_test.rb","test/models/observers.rb","test/observer_array_test.rb","test/observing_test.rb","test/rake_test.rb","test/sweeper_test.rb","test/transaction_callbacks_test.rb"]
+  s.files         = [".gitignore",".travis.yml","Gemfile","LICENSE","README.md","Rakefile","lib/generators/active_record/observer/observer_generator.rb","lib/generators/active_record/observer/templates/observer.rb","lib/generators/rails/observer/USAGE","lib/generators/rails/observer/observer_generator.rb","lib/generators/test_unit/observer/observer_generator.rb","lib/generators/test_unit/observer/templates/unit_test.rb","lib/rails-observers.rb","lib/rails/observers/action_controller/caching.rb","lib/rails/observers/action_controller/caching/sweeping.rb","lib/rails/observers/active_model/active_model.rb","lib/rails/observers/active_model/observer_array.rb","lib/rails/observers/active_model/observing.rb","lib/rails/observers/activerecord/active_record.rb","lib/rails/observers/activerecord/base.rb","lib/rails/observers/activerecord/observer.rb","lib/rails/observers/railtie.rb","lib/rails/observers/version.rb","rails-observers.gemspec","rails-observers.gemspec.erb","test/configuration_test.rb","test/console_test.rb","test/fixtures/developers.yml","test/fixtures/minimalistics.yml","test/fixtures/topics.yml","test/generators/generators_test_helper.rb","test/generators/namespaced_generators_test.rb","test/generators/observer_generator_test.rb","test/helper.rb","test/isolation/abstract_unit.rb","test/lifecycle_test.rb","test/models/observers.rb","test/observer_array_test.rb","test/observing_test.rb","test/rake_test.rb","test/sweeper_test.rb","test/transaction_callbacks_test.rb"]
   s.test_files    = ["test/configuration_test.rb","test/console_test.rb","test/fixtures/developers.yml","test/fixtures/minimalistics.yml","test/fixtures/topics.yml","test/generators/generators_test_helper.rb","test/generators/namespaced_generators_test.rb","test/generators/observer_generator_test.rb","test/helper.rb","test/isolation/abstract_unit.rb","test/lifecycle_test.rb","test/models/observers.rb","test/observer_array_test.rb","test/observing_test.rb","test/rake_test.rb","test/sweeper_test.rb","test/transaction_callbacks_test.rb"]
   s.executables   = []
   s.require_paths = ["lib"]
 
-  s.add_dependency 'railties', '~> 4.0.0.beta'
-
   s.add_development_dependency 'minitest',     '>= 3'
+  s.add_development_dependency 'railties', '~> 4.0.0.beta'
   s.add_development_dependency 'activerecord', '~> 4.0.0.beta'
   s.add_development_dependency 'activemodel', '~> 4.0.0.beta'
   s.add_development_dependency 'actionmailer', '~> 4.0.0.beta'

rails-observers.gemspec.erb

@@ -15,9 +15,8 @@ Gem::Specification.new do |s|
   s.executables   = [<%= executables.map(&:inspect).join ',' %>]
   s.require_paths = ["lib"]
 
-  s.add_dependency 'railties', '~> 4.0.0.beta'
-
   s.add_development_dependency 'minitest',     '>= 3'
+  s.add_development_dependency 'railties', '~> 4.0.0.beta'
   s.add_development_dependency 'activerecord', '~> 4.0.0.beta'
   s.add_development_dependency 'activemodel', '~> 4.0.0.beta'
   s.add_development_dependency 'actionmailer', '~> 4.0.0.beta'