我想出了一个巧妙的方法,在Rails 3.x gem中扩展ApplicationController。
在我的gem的lib/my_namespace/my_controller.rb
文件中,我写下了如下代码:
class MyNamespace::MyController < ApplicationController
before_filter :some_method
after_filter :another_method
def initialize
# getting classname of the subclass to use for lookup of the associated model, etc.
# and storing the model_class in an instance variable
# ...
end
# define :some_method, :another_method, etc.
# ...
private
attr_accessor :subclass_defined_during_initialize # etc.
# etc.
end
但是当 Gem 加载时,app/controllers/application_controller.rb
还未加载,因此会失败:
/path/to/rvm/gemset/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:
in `require': cannot load such file -- my_gem_name/application_controller (LoadError)
作为解决方法,我在我的宝石的
lib/gem_namespace/application_controller.rb
中定义了ApplicationController:class ApplicationController < ActionController::Base
end
我假设即使我已经在那里定义它,在我的Rails 3应用程序的
app/controllers/application_controller.rb
中会重新定义它,这样扩展ApplicationController
的应用程序中的两个控制器和扩展MyNamespace::MyController
的控制器都将直接或间接地扩展在app/controllers/application_controller.rb
中定义的ApplicationController。
然而,我们注意到在加载gem之后,扩展ApplicationController
的控制器无法访问在app/controllers/application_controller.rb
中定义的方法。此外,ApplicationHelper
(app/helpers/application_helper.rb)
模块不再被其他帮助程序模块加载。
如何在我的gem中的控制器中扩展ApplicationController
,以定义before_filter
和after_filter
,并使用initialize
访问类名来确定关联的模型类,然后可以在其方法中存储和使用?
更新2012/10/22:
这是我想出来的:
在lib/your_gem_name/railtie.rb
中:
module YourGemsModuleName
class Railtie < Rails::Railtie
initializer "your_gem_name.action_controller" do
ActiveSupport.on_load(:action_controller) do
puts "Extending #{self} with YourGemsModuleName::Controller"
# ActionController::Base gets a method that allows controllers to include the new behavior
include YourGemsModuleName::Controller # ActiveSupport::Concern
end
end
end
在
lib/your_gem_name/controller.rb
中:module YourGemsModuleName
module Controller
extend ActiveSupport::Concern
# note: don't specify included or ClassMethods if unused
included do
# anything you would want to do in every controller, for example: add a class attribute
class_attribute :class_attribute_available_on_every_controller, instance_writer: false
end
module ClassMethods
# notice: no self.method_name here, because this is being extended because ActiveSupport::Concern was extended
def make_this_controller_fantastic
before_filter :some_instance_method_available_on_every_controller # to be available on every controller
after_filter :another_instance_method_available_on_every_controller # to be available on every controller
include FantasticStuff
end
end
# instance methods to go on every controller go here
def some_instance_method_available_on_every_controller
puts "a method available on every controller!"
end
def another_instance_method_available_on_every_controller
puts "another method available on every controller!"
end
module FantasticStuff
extend ActiveSupport::Concern
# note: don't specify included or ClassMethods if unused
included do
class_attribute :class_attribute_only_available_on_fantastic_controllers, instance_writer: false
end
module ClassMethods
# class methods available only if make_this_controller_fantastic is specified in the controller
def some_fanastic_class_method
put "a fantastic class method!"
end
end
# instance methods available only if make_this_controller_fantastic is specified in the controller
def some_fantastic_instance_method
puts "a fantastic instance method!"
end
def another_fantastic_instance_method
puts "another fantastic instance method!"
end
end
end
end