Add following/followers

Author: tk

app/assets/stylesheets/custom.css.scss

@@ -212,3 +212,32 @@ aside {
     margin-bottom: 5px;
   }
 }
+
+.stats {
+  overflow: auto;
+  a {
+    float: left;
+    padding: 0 10px;
+    border-left: 1px solid $grayLighter;
+    color: gray;
+    &:first-child {
+      padding-left: 0;
+      border: 0;
+    }
+    &:hover {
+      text-decoration: none;
+      color: $blue;
+    }
+  }
+  strong {
+    display: block;
+  }
+}
+
+.user_avatars {
+  overflow: auto;
+  margin-top: 10px;
+  .gravatar {
+    margin: 1px 1px;
+  }
+}

app/controllers/relationships_controller.rb

@@ -0,0 +1,21 @@
+class RelationshipsController < ApplicationController
+  before_filter :signed_in_user
+
+  def create
+    @user = User.find(params[:relationship][:leader_id])
+    current_user.follow!(@user)
+    respond_to do |format|
+      format.html { redirect_to @user }
+      format.js
+    end
+  end
+
+  def destroy
+    @user = Relationship.find(params[:id]).leader
+    current_user.unfollow!(@user)
+    respond_to do |format|
+      format.html { redirect_to @user }
+      format.js
+    end
+  end
+end

app/controllers/users_controller.rb

@@ -1,5 +1,6 @@
 class UsersController < ApplicationController
-  before_filter :signed_in_user,  only: [:edit, :update, :index, :destroy]
+  before_filter :signed_in_user,
+        only: [:edit, :update, :index, :destroy, :following, :followers]
   before_filter :correct_user,    only: [:edit, :update]
   before_filter :admin_user,      only: :destroy
 
@@ -54,6 +55,20 @@ def destroy
     redirect_to users_url
   end
 
+  def following
+    @title = "Following"
+    @user = User.find(params[:id])
+    @users = @user.leaders.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
+
   private
 
     def correct_user

app/models/micropost.rb

@@ -20,4 +20,12 @@ class Micropost < ActiveRecord::Base
   validates :content, presence: true, length: { maximum: MAX_LENGTH }
 
   default_scope order: 'microposts.created_at DESC'
+
+  def self.from_users_followed_by(user)
+    leader_ids = "SELECT leader_id FROM relationships
+                     WHERE follower_id = :user_id"
+    where("user_id IN (#{leader_ids}) OR user_id = :user_id",
+      user_id: user)
+  end
+
 end

app/models/relationship.rb

@@ -0,0 +1,20 @@
+# == Schema Information
+#
+# Table name: relationships
+#
+#  id          :integer          not null, primary key
+#  follower_id :integer
+#  leader_id   :integer
+#  created_at  :datetime         not null
+#  updated_at  :datetime         not null
+#
+
+class Relationship < ActiveRecord::Base
+  attr_accessible :leader_id
+
+  belongs_to :follower, class_name: "User"
+  belongs_to :leader, class_name: "User"
+
+  validates :follower_id, presence: true
+  validates :leader_id, presence: true
+end

app/models/user.rb

@@ -13,29 +13,46 @@
 #
 
 class User < ActiveRecord::Base
-	attr_accessible :name, :email, :password, :password_confirmation
+  attr_accessible :name, :email, :password, :password_confirmation
   has_secure_password
   has_many :microposts, dependent: :destroy
+  has_many :relationships, foreign_key: "follower_id", dependent: :destroy
+  has_many :leaders, through: :relationships
+  has_many :reverse_relationships, foreign_key: "leader_id",
+                                   class_name:  "Relationship",
+                                   dependent:   :destroy
+  has_many :followers, through: :reverse_relationships
 
-	before_save { self.email.downcase! }
-	before_save :create_remember_token
+  before_save { self.email.downcase! }
+  before_save :create_remember_token
 
   validates :name,  presence: true, length: { maximum: 50 }
-	VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
+  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
   validates :email, presence: true, format: { with: VALID_EMAIL_REGEX },
   	uniqueness: { case_sensitive: false }
   validates :password, length: { minimum: 6 }
   validates :password_confirmation, presence: true
 
   def feed
-    # This is preliminary. See "Following users" for the full implementation.
-    Micropost.where("user_id = ?", id)
+    Micropost.from_users_followed_by(self)
   end
 
-	private
+  def following?(other_user)
+    relationships.find_by_leader_id(other_user.id)
+  end
+
+  def follow!(other_user)
+    relationships.create!(leader_id: other_user.id)
+  end
+
+  def unfollow!(other_user)
+    relationships.find_by_leader_id(other_user.id).destroy
+  end
+
+  private
 
-	  def create_remember_token
-		  self.remember_token = SecureRandom.urlsafe_base64
-	  end
+    def create_remember_token
+      self.remember_token = SecureRandom.urlsafe_base64
+    end
 
 end

app/views/relationships/create.js.erb

@@ -0,0 +1,2 @@
+$("#follow_form").html("<%= j render('users/unfollow') %>")
+$("#followers").html('<%= @user.followers.count %>')

app/views/relationships/destroy.js.erb

@@ -0,0 +1,2 @@
+$("#follow_form").html("<%= j render('users/follow') %>")
+$("#followers").html('<%= @user.followers.count %>')

app/views/shared/_stats.html.erb

@@ -0,0 +1,15 @@
+<% @user ||= current_user %>
+<div class="stats">
+  <a href="<%= following_user_path(@user) %>">
+    <strong id="following" class="stat">
+      <%= @user.leaders.count %>
+    </strong>
+    following
+  </a>
+  <a href="<%= followers_user_path(@user) %>">
+    <strong id="followers" class="stat">
+      <%= @user.followers.count %>
+    </strong>
+    followers
+  </a>
+</div>

app/views/static_pages/_home_signed_in.html.erb

@@ -3,6 +3,9 @@
     <section>
       <%= render 'shared/user_info' %>
     </section>
+    <section>
+      <%= render 'shared/stats' %>
+    </section>
     <section>
       <%= render 'shared/micropost_form' %>
     </section>

app/views/users/_follow.html.erb

@@ -0,0 +1,5 @@
+<%= form_for(current_user.relationships.build(leader_id: @user.id),
+    remote: true) do |f| %>
+  <div><%= f.hidden_field :leader_id %></div>
+  <%= f.submit "Follow", class: "btn btn-large btn-primary" %>
+<% end %>

app/views/users/_follow_form.html.erb

@@ -0,0 +1,9 @@
+<% unless current_user?(@user) %>
+  <div id="follow_form">
+  <% if current_user.following?(@user) %>
+    <%= render 'unfollow' %>
+  <% else %>
+    <%= render 'follow' %>
+  <% end %>
+  </div>
+<% end %>

app/views/users/_unfollow.html.erb

@@ -0,0 +1,4 @@
+<%= form_for(current_user.relationships.find_by_leader_id(@user),
+             html: { method: :delete }, remote: true) do |f| %>
+  <%= f.submit "Unfollow", class: "btn btn-large" %>
+<% end %>

app/views/users/show.html.erb

@@ -7,8 +7,12 @@
         <%= @user.name %>
       </h1>
     </section>
+    <section>
+      <%= render 'shared/stats' %>
+    </section>
   </aside>
   <div class="span8">
+    <%= render 'follow_form' if signed_in? %>
     <% if @user.microposts.any? %>
       <h3>Microposts (<%= @user.microposts.count %>)</h3>
       <ol class="microposts">

app/views/users/show_follow.html.erb

@@ -0,0 +1,30 @@
+<% provide(:title, @title) %>
+<div class="row">
+  <aside class="span4">
+    <section>
+      <%= gravatar_for @user %>
+      <h1><%= @user.name %></h1>
+      <span><%= link_to "view my profile", @user %></span>
+      <span><b>Microposts:</b> <%= @user.microposts.count %></span>
+    </section>
+    <section>
+      <%= render 'shared/stats' %>
+      <% if @users.any? %>
+        <div class="user_avatars">
+          <% @users.each do |user| %>
+            <%= link_to gravatar_for(user, size: 30), user %>
+          <% end %>
+        </div>
+      <% end %>
+    </section>
+  </aside>
+  <div class="span8">
+    <h3><%= @title %></h3>
+    <% if @users.any? %>
+      <ul class="users">
+        <%= render @users %>
+      </ul>
+      <%= will_paginate %>
+    <% end %>
+  </div>
+</div>

config/routes.rb

@@ -1,7 +1,12 @@
 SampleApp::Application.routes.draw do
-  resources :users
+  resources :users do
+    member do
+      get :following, :followers
+    end
+  end
   resources :sessions, only: [:new, :create, :destroy]
   resources :microposts, only: [:create, :destroy]
+  resources :relationships, only: [:create, :destroy]
 
   root to: 'static_pages#home'
   match '/signup',  to: 'users#new'

db/migrate/20121116080832_create_relationships.rb

@@ -0,0 +1,14 @@
+class CreateRelationships < ActiveRecord::Migration
+  def change
+    create_table :relationships do |t|
+      t.integer :follower_id
+      t.integer :leader_id
+
+      t.timestamps
+    end
+
+    add_index :relationships, :follower_id
+    add_index :relationships, :leader_id
+    add_index :relationships, [:follower_id, :leader_id], unique: true
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20121113195507) do
+ActiveRecord::Schema.define(:version => 20121116080832) do
 
   create_table "microposts", :force => true do |t|
     t.string   "content"
@@ -22,6 +22,17 @@
 
   add_index "microposts", ["user_id", "created_at"], :name => "index_microposts_on_user_id_and_created_at"
 
+  create_table "relationships", :force => true do |t|
+    t.integer  "follower_id"
+    t.integer  "leader_id"
+    t.datetime "created_at",  :null => false
+    t.datetime "updated_at",  :null => false
+  end
+
+  add_index "relationships", ["follower_id", "leader_id"], :name => "index_relationships_on_follower_id_and_leader_id", :unique => true
+  add_index "relationships", ["follower_id"], :name => "index_relationships_on_follower_id"
+  add_index "relationships", ["leader_id"], :name => "index_relationships_on_leader_id"
+
   create_table "users", :force => true do |t|
     t.string   "name"
     t.string   "email"

lib/tasks/sample_data.rake

@@ -1,24 +1,42 @@
 namespace :db do
   desc "Fill database with sample data"
   task populate: :environment do
-    admin = User.create!(name: "Example User",
-                 email: "[email protected]",
-                 password: "foobar",
-                 password_confirmation: "foobar")
-    admin.toggle!(:admin)
-    99.times do |n|
-      name  = Faker::Name.name
-      email = "example-#{n+1}@railstutorial.org"
-      password  = "password"
-      User.create!(name: name,
-                   email: email,
-                   password: password,
-                   password_confirmation: password)
-    end
+    make_users
+    make_microposts
+    make_relationships
+  end
+end
+
+def make_users
+  admin = User.create!(name: "Example User",
+               email: "[email protected]",
+               password: "foobar",
+               password_confirmation: "foobar")
+  admin.toggle!(:admin)
 
-    users = User.all(limit: 6)
-    users.each do |user|
-      50.times { user.microposts.create!(content: Faker::Lorem.sentence(5)) }
-    end
+  99.times do |n|
+    name  = Faker::Name.name
+    email = "example-#{n+1}@railstutorial.org"
+    password  = "password"
+    User.create!(name: name,
+                 email: email,
+                 password: password,
+                 password_confirmation: password)
   end
+end
+
+def make_microposts
+  users = User.all(limit: 6)
+  users.each do |user|
+    50.times { user.microposts.create!(content: Faker::Lorem.sentence(5)) }
+  end
+end
+
+def make_relationships
+  users = User.all
+  user  = users.first
+  leaders   = users[2..50]
+  followers = users[3..40]
+  leaders.each    { |leader| user.follow!(leader) }
+  followers.each  { |follower| follower.follow!(user) }
 end