Displaying attributes for associated models in views - ruby-on-rails

Question

I want to fetch username or email( both are in user table) of user who creates article in blog application. Currently I am able to fetch user id from articles_controller.rb
def create
#article = Article.new(params[:article])
#article.user_id = current_user.id
#article.save
redirect_to article_path(#article)
end
but no idea how to fetch username or email for same. Basically I want to display username or email on article index page. Please suggest me to how to get done it
user.rb
class User < ActiveRecord::Base
has_many :articles
has_many :comments
# Include default devise modules. Others available are:
# :token_authenticatable, :confirmable,
# :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :username, :email, :password, :password_confirmation, :remember_me
attr_accessible :title, :body
end
article.rb
class Article < ActiveRecord::Base
attr_accessible :title, :body
has_many :comments
belongs_to :user
end
articles_controller.rb
class ArticlesController < ApplicationController
def index
#articles = Article.all
end
def show
#article = Article.find(params[:id])
end
def new
#article = Article.new
end
def create
#article = Article.new(params[:article])
#article.user_id = current_user.id
#article.save
redirect_to article_path(#article)
end
def destroy
#article = Article.find(params[:id])
#article.destroy
redirect_to action: 'index'
end
def edit
#article = Article.find(params[:id])
end
def update
#article = Article.find(params[:id])
#article.update_attributes(params[:article])
flash.notice = "Article '#{#article.title}' Updated!"
redirect_to article_path(#article)
end
end
article/index.html.erb
<div style="color:#666666; margin-top:10px"> <%= article.created_at %></div>
<div style="color:#666666; margin-top:10px"> <%= article.user_id %></div>
Articles table
class CreateArticles < ActiveRecord::Migration
def change
create_table :articles do |t|
t.string :title
t.text :body
t.timestamps
end
add_index :articles, [:user_id, :created_at]
end
end
I am able to fetch user id in views but no idea how to username or email.
Any help would be appreciated.

Answer 1

You have defined a user association on your Article model class with belongs_to :user. This creates a user method on Article that returns the associated user so you in your view:
<%= article.user.email %>
will output the email of the associated user, or:
<%= article.user.email if article.user %>
to cater for nil user values. Alternatively write a helper to factor this logic out of the view.

Answer 2

Already you set relation between the Article & User model. So in your article index page you have all articles in #articles variable. So easily you can get the particular user of a particular article using below code,
#articles.each do |article|
user = article.user #gives the user of this current article. From this
#objecct you can easily get the username, email or everything specific to user.
email = user.email #gives email of article's user or you can directly give artile.user.email
end
like this you can get all the attribute of user.