Question

I am getting the below error for line 8. Learning from ch.11/12 of the railstutorial.org. I am using rails 3.1.3 and ruby 1.9.3 instead of what was suggested from the tutorial. I’ve looked around for others with the same error and haven’t been able to find another example of this problem. Still a newbie to rails and this is my first post. Please help! Teach me what I missed. Thanks!

NoMethodError in Users#show

undefined method `following' for #<User:0xab068f0>

Extracted source (around line #8):

5:       <td>
6:         <a href="<%= following_user_path(@user) %>">
7:           <span id="following" class="stat">
8:             <%= @user.following.count %> following
9:           </span>
10:         </a>
11:       </td>

Trace of template inclusion: app/views/users/show.html.erb

app/views/shared/_stats.html.erb:8:in `_app_views_shared__stats_html_erb__794775909_89084750'
app/views/users/show.html.erb:32:in `_app_views_users_show_html_erb__961188432_91976190'

Full Trace:

activemodel (3.1.3) lib/active_model/attribute_methods.rb:385:in `method_missing'
activerecord (3.1.3) lib/active_record/attribute_methods.rb:60:in `method_missing'
app/views/shared/_stats.html.erb:8:in `_app_views_shared__stats_html_erb__794775909_89084750'

show.html.erb

31: <%= render 'shared/stats' %>
32: <%= render 'shared/user_info' %>

_stats.html.erb

<% @user ||= current_user %>
<div class="stats">
  <table summary="User stats">
    <tr>
      <td>
        <a href="<%= following_user_path(@user) %>">
          <span id="following" class="stat">
            <%= @user.following.count %> following
          </span>
        </a>
      </td>
      <td>
        <a href="<%= followers_user_path(@user) %>">
          <span id="followers" class="stat">
            <%= pluralize(@user.followers.count, "follower") %>
          </span>
        </a>
      </td>
    </tr>
  </table>
</div>

models/relationship.rb

class Relationship < ActiveRecord::Base
  attr_accessible :followed_id

   belongs_to :follower, :class_name => "User"
   belongs_to :followed, :class_name => "User"

   validates :follower_id, :presence => true
   validates :followed_id, :presence => true

end

db/migrate/…_create_relationships.rb

class CreateRelationships < ActiveRecord::Migration
  def self.up
    create_table :relationships do |t|
      t.integer :follower_id
      t.integer :followed_id

      t.timestamps
    end
    add_index :relationships, :follower_id
    add_index :relationships, :followed_id
    add_index :relationships, [:follower_id, :followed_id], :unique => true
  end

  def self.down
    drop_table :relationships
  end
end

Edit: Here is the user.rb file

require 'digest'
class User < ActiveRecord::Base

attr_accessor :password
attr_accessible :first_name, :last_name, :email, :password, 
                :salt, :password_confirmation, :zip_id, 
                :country, :birthdate, :gender, :photo



     #paperclip
  has_attached_file :photo, 
      :default_url => ":rails_root/public/images/default.png",
      :url => "/images/user_photos/:id/:style/:basename.:extension",
      :path => ":rails_root/public/images/user_photos/:id/:style/:basename.:extension",
      :styles => { 
        :thumb => "150x150",
        :small  => "250x250" }  

validates_attachment_size :photo, :less_than => 5.megabytes
validates_attachment_content_type :photo, :content_type => ['image/jpeg', 'image/png']

    # associates microposts to users.  The second part will destroy all posts by this user if you destroy the user
    has_many :microposts, :dependent => :destroy

  def feed
    Micropost.from_users_followed_by(self)    
  end

  has_many :reverse_relationships, :foreign_key => "followed_id",
                                   :class_name => "Relationship",
                                   :dependent => :destroy
  has_many :followers, :through => :reverse_relationships, :source => :follower


  def following?(followed)
    relationships.find_by_followed_id(followed)
  end

  def follow!(followed)
    relationships.create!(:followed_id => followed.id)
  end

  def unfollow!(followed)
    relationships.find_by_followed_id(followed).destroy
  end




email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i

validates :first_name,  :presence => true,
                        :length   => { :maximum => 30 }
validates :last_name,   :presence => true,
                        :length   => { :maximum => 30 }
validates :email,       :presence => true,
                        :format   => { :with => email_regex },
                        :uniqueness => { :case_sensitive => false },
                        :length   => { :maximum => 50 }
validates :zip_id,      :presence => true,
                        :length       => { :within => 5..5 }, :numericality => true

validates :password,    :presence => true,
                        :length       => { :within => 6..40 },
                        :confirmation => true                       
  before_save :encrypt_password

  def has_password?(submitted_password)
    encrypted_password == encrypt(submitted_password)
  end

  def self.authenticate(email, submitted_password)
    user = find_by_email(email)
    return nil  if user.nil?
    return user if user.has_password?(submitted_password)
  end

  private

    def encrypt_password
      self.salt = make_salt unless has_password?(password)
      self.encrypted_password = encrypt(password)
    end

    def encrypt(string)
      secure_hash("#{salt}--#{string}")
    end

    def make_salt
      secure_hash("#{Time.now.utc}--#{password}")
    end

    def secure_hash(string)
      Digest::SHA2.hexdigest(string)
    end

    def self.authenticate(email, submitted_password)
    user = find_by_email(email)
    return nil  if user.nil?
    return user if user.has_password?(submitted_password)
  end

  def self.authenticate_with_salt(id, cookie_salt)
    user = find_by_id(id)
    (user && user.salt == cookie_salt) ? user : nil
  end


end

Here is the following/followers from: controllers/users_controller.rb

  def following
    @title = "Following"
    @user = User.find(params[:id])
    @users = @user.following.paginate(:page => params[:page])
    render 'show_follow'
  end

  def followers
    @title = "Followers"
    @user = User.find(params[:id])
    @users = @user.followers.paginate(:page => params[:page])
    render 'show_follow'
  end

Answer 1

Firstly, 3.1.3 is the Rails Version and 1.8.7 seems to be Ruby Version rather than Rails. You should correct it. And there isn’t following method in the user model according to what you’ve posted in the question. There is only following?(followed) method and other methods but not following method.

I think you’re missing this part in your User class:

class User < ActiveRecord::Base
  .
  has_many :following, :through => :relationships, :source => :followed
  .
end

See section 12.11 of the online book for more details.

After adding that line, and since now @user will have #following method to call to you can say @user.following.count and it won’t throw an error.