Implement advanced login

app/assets/stylesheets/custom.scss

@@ -170,3 +170,18 @@ input {
     color: $state-danger-text;
   }
 }
+
+.checkbox {
+  margin-top: -10px;
+  margin-bottom: 10px;
+
+  span {
+    margin-left: 20px;
+    font-weight: normal;
+  }
+}
+
+#session_remember_me {
+  width: auto;
+  margin-left: 0;
+}
\ No newline at end of file

app/controllers/sessions_controller.rb

@@ -6,6 +6,7 @@ class SessionsController < ApplicationController
     user = User.find_by(email: params[:session][:email].downcase)
     if user && user.authenticate(params[:session][:password])
       log_in user
+      params[:session][:remember_me] == '1' ? remember(user) : forget(user)
       redirect_to user
     else
       flash.now[:danger] = "Invalid email/password combination"
@@ -14,7 +15,7 @@ class SessionsController < ApplicationController
   end
 
   def destroy
-    log_out
+    log_out if logged_in?
     redirect_to root_url
   end
 end

app/helpers/sessions_helper.rb

@@ -3,15 +3,39 @@ module SessionsHelper
     session[:user_id] = user.id
   end
 
+  # remember a user in a persistent session
+  def remember(user)
+    user.remember
+    cookies.permanent.signed[:user_id] = user.id
+    cookies.permanent[:remember_token] = user.remember_token
+  end
+
+  # return the user corresponding to the remember token cookie
   def current_user
-    @current_user ||= User.find_by(id: session[:user_id])
+    if user_id = session[:user_id]
+      @current_user ||= User.find_by(id: user_id)
+    elsif user_id = cookies.signed[:user_id]
+      user = User.find_by(id: user_id)
+      if user && user.authenticated?(cookies[:remember_token])
+        log_in user
+        @current_user = user
+      end
+    end
   end
 
   def logged_in?
     !current_user.nil?
   end
 
+  #forgets a persistent session
+  def forget(user)
+    user.forget
+    cookies.delete(:user_id)
+    cookies.delete(:remember_token)
+  end
+
   def log_out
+    forget(current_user)
     session.delete(:user_id)
     @current_user = nil
   end

app/models/user.rb

 class User < ApplicationRecord
+  attr_accessor :remember_token
+
   before_save { email.downcase! }
+  
   validates :name, presence: true, length: { maximum: 50 }
 
   VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
@@ -14,4 +17,23 @@ class User < ApplicationRecord
                                                   BCrypt::Engine.cost
     BCrypt::Password.create(string, cost: cost)
   end
+
+  # return a random token
+  def User.new_token
+    SecureRandom.urlsafe_base64
+  end
+
+  def remember
+    self.remember_token = User.new_token
+    update_attribute :remember_digest, User.digest(remember_token)
+  end
+
+  def authenticated?(remember_token)
+    return false if remember_digest.nil?
+    BCrypt::Password.new(remember_digest).is_password?(remember_token)
+  end
+
+  def forget
+    update_attribute(:remember_digest, nil)
+  end
 end

app/views/sessions/new.html.erb

@@ -10,6 +10,11 @@
       <%= f.label :password %>
       <%= f.password_field :password, class: 'form-control' %>
 
+      <%= f.label :remember_me, class: "checkbox inline" do %>
+        <%= f.check_box :remember_me %>
+        <span>Remember me on this computer</span>
+      <% end %>
+
       <%= f.submit 'Log in', class: "btn btn-primary" %>
     <% end %>
 

db/migrate/20180806093756_add_remember_digest_to_users.rb

+class AddRememberDigestToUsers < ActiveRecord::Migration[5.2]
+  def change
+    add_column :users, :remember_digest, :string
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_08_02_015202) do
+ActiveRecord::Schema.define(version: 2018_08_06_093756) do
 
   create_table "users", force: :cascade do |t|
     t.string "name"
@@ -18,6 +18,7 @@ ActiveRecord::Schema.define(version: 2018_08_02_015202) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.string "password_digest"
+    t.string "remember_digest"
     t.index ["email"], name: "index_users_on_email", unique: true
   end
 

test/helpers/sessions_helper_test.rb

+require "test_helper"
+
+class SessionsHelperTest < ActionView::TestCase
+  def setup
+    @user = users(:michael)
+    remember @user
+  end
+
+  test "current_user returns right user when session is nil" do
+    assert_equal @user, current_user
+    assert is_logged_in?
+  end
+
+  test "current_user returns nil when remember digest is wrong" do
+    @user.update_attribute :remember_digest, User.digest(User.new_token)
+    assert_nil current_user
+  end
+end
\ No newline at end of file

test/integration/users_login_test.rb

@@ -29,9 +29,24 @@ class UsersLoginTest < ActionDispatch::IntegrationTest
     delete logout_path
     assert_not is_logged_in?
     assert_redirected_to root_url
+    # simulate a user clicking logout in a second window
+    delete logout_path
     follow_redirect!
     assert_select "a[href=?]", login_path
     assert_select "a[href=?]", logout_path, count: 0
     assert_select "a[href=?]", user_path(@user), count: 0
   end
+
+  test "login with remembering" do
+    log_in_as @user, remember_me: '1'
+    assert_not_empty cookies['remember_token']
+  end
+
+  test 'login without remembering' do
+    # log in to set the cookie
+    log_in_as @user, remember_me: '1'
+    # log in again and verify that the cookie is deleted.
+    log_in_as @user, remember_me: '0'
+    assert_empty cookies['remember_token']
+  end
 end

test/models/user_test.rb

@@ -71,4 +71,8 @@ class UserTest < ActiveSupport::TestCase
     @user.password = @user.password_confirmation = "a" * 5
     assert_not @user.valid?
   end
+
+  test "authenticated? should return false for a user with nil digest" do
+    assert_not @user.authenticated?('')
+  end
 end

test/test_helper.rb

@@ -11,4 +11,17 @@ class ActiveSupport::TestCase
   def is_logged_in?
     !session[:user_id].nil?
   end
+
+  #log in as a particular user
+  def log_in_as(user)
+    session[:user_id] = user.id
+  end
+end
+
+class ActionDispatch::IntegrationTest
+  #log in as a particular user
+  def log_in_as(user, password: 'password', remember_me: '1')
+    post login_path, params: { session: { email: user.email, password: password,
+                                          remember_me: remember_me } }
+  end
 end