self.included like a constructor method that gets called when a module is included in a class?

rubyonrails-talk
1

Hey all,

Let's say you have a controller class and you include a module:

class ApplicationController < ActionController::Base   include AuthenticationSystem

  def default_page     case       when cu.group_is?(:a) then a_path       when cu.group_is?(:b) then b_path       when cu.group_is?(:c) then c_path     end   end end

Notice how this method makes a call to method cu. Now in order for cu to exist, that means the module methods must be copied into ApplicationController before any of its methods are called by subclasses:

class DashboardController < ApplicationController   def root     redirect_to default_page   end end

If the module methods were not included prior to default_page being called in ApplicationController, since default_page calls method cu defined in the module AuthenticationSystem, it would throw error.

That part is clear. But what is unclear is what's the whole purpose of this:

module AuthenticationSystem   def self.included(base)     base.send :helper_method, :current_user   end end

If, for example, current_user setter/getter are already declared in module:

  def current_user     @current_user = User.find_by_id(session[:user_id])   end

  alias :cu :current_user

  def current_user=(new_user)     session[:user_id] = new_user ? new_user.id : nil     @current_user = new_user   end

and thus will be copied into the ApplicationController class, then what's the point of sending it to the class using base.send when it will already be copied into the class?

Or is base.send like a contructor method that gets executed before anything else in the module and therefore when its included in a class, it acts as consutrcotr of class and gets called prior to any methods of the class being called?

Thanks for response.

2

Hey all,

Let's say you have a controller class and you include a module:

module AuthenticationSystem def self.included(base) base.send :helper_method, :current_user end end

The point of this is to call helper_method :current_user. You can look up what helper_method does in the rails docs.

Fred

3

The point of this is to call helper_method :current_user. You can look up what helper_method does in the rails docs.

Fred

ok so basically this allows you to use current_user in your views.

thanks for response