module AbstractController module Helpers extend ActiveSupport::Concern include Renderer included do extlib_inheritable_accessor(:_helpers) { Module.new } end # Override AbstractController::Renderer's _action_view to include the # helper module for this class into its helpers module. def _action_view @_action_view ||= super.tap { |av| av.helpers.include(_helpers) } end module ClassMethods # When a class is inherited, wrap its helper module in a new module. # This ensures that the parent class's module can be changed # independently of the child class's. def inherited(klass) helpers = _helpers klass._helpers = Module.new { include helpers } super end # Declare a controller method as a helper. For example, the following # makes the +current_user+ controller method available to the view: # class ApplicationController < ActionController::Base # helper_method :current_user, :logged_in? # # def current_user # @current_user ||= User.find_by_id(session[:user]) # end # # def logged_in? # current_user != nil # end # end # # In a view: # <% if logged_in? -%>Welcome, <%= current_user.name %><% end -%> # # ==== Parameters # meths:: The name of a method on the controller # to be made available on the view. def helper_method(*meths) meths.flatten.each do |meth| _helpers.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1 def #{meth}(*args, &blk) controller.send(%(#{meth}), *args, &blk) end ruby_eval end end # Make a number of helper modules part of this class' default # helpers. # # ==== Parameters # *args:: Modules to be included # block:: Evalulate the block in the context # of the helper module. Any methods defined in the block # will be helpers. def helper(*args, &block) args.flatten.each do |arg| case arg when Module add_template_helper(arg) end end _helpers.module_eval(&block) if block_given? end private # Makes all the (instance) methods in the helper module available to templates # rendered through this controller. # # ==== Parameters # mod:: The module to include into the current helper module # for the class def add_template_helper(mod) _helpers.module_eval { include mod } end end end end