Rails 2.3.8 How is 'id' passed to method in pagination example?

Question

I'm working through "Learning Rails by Example" tutorial by Michael Hartl(11.33).The relevant code is:

---

class PagesController < ApplicationController

def home

@title = "Home"
if signed_in?
  @micropost = Micropost.new
   @feed_items = current_user.feed.paginate(:page => params[:page])
end

end

---

class User < ActiveRecord::Base

def feed

Micropost.all(:conditions => ["user_id = ?", id])

end

---

module SessionsHelper

def sign_in(user)

user.remember_me!
cookies[:remember_token] = { :value   => user.remember_token,
                             :expires => 20.years.from_now.utc }
self.current_user= user

end

def current_user=(user)

@current_user = user

end

def current_user

@current_user ||= user_from_remember_token

end

---

@feed_items is then rendered as a collection to "will_paginate" and everything works fine.

My problem is that I cannot understand how the current_user is passed to the "feed" method in the PagesController line ie

"@feed_items = current_user.feed.paginate(:page => params[:page])"

Any help will be greatly appreciated

Alan

Answer 1

Most likely "current_user" is defined in the paret class of your controller: ApplicationController. Search for "application_controller.rb" in your controller directory.

Answer 2

current_user is never "passed" to the feed method - the feed method is called on the current_user object. Take a look at the User model:

def feed
  Micropost.all(:conditions => ["user_id = ?", id])
end

This is an instance method which is executed when you call current_user.feed. The id in the :conditions hash refers to the id of the user object instance, in this case current_user.