Implement basic login

app/assets/javascripts/application.js

@@ -9,7 +9,8 @@
 //
 // Read Sprockets README (https://github.com/rails/sprockets#sprockets-directives) for details
 // about supported directives.
-//
+//= require jquery
+//= require bootstrap
 //= require rails-ujs
 //= require turbolinks
 //= require_tree .

app/assets/javascripts/sessions.coffee

+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/stylesheets/sessions.scss

+// Place all the styles related to the Sessions controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/controllers/application_controller.rb

+# That
 class ApplicationController < ActionController::Base
   protect_from_forgery with: :exception
-
-  def hello 
-    render html: "hello, world!"
-  end 
+  include SessionsHelper
 end

app/controllers/sessions_controller.rb

+class SessionsController < ApplicationController
+  def new
+  end
+
+  def create
+    user = User.find_by(email: params[:session][:email].downcase)
+    if user && user.authenticate(params[:session][:password])
+      # Log the user in and redirect to the user's show page.
+      log_in user
+      redirect_to user
+    else
+      # Create an error message.
+      flash.now[:danger] = 'Invalid email/password combination'
+      render 'new'
+    end
+  end
+
+  # Logs out the current user.
+  def log_out
+    session.delete(:user_id)
+    @current_user = nil
+  end
+
+  def destroy
+    log_out
+    redirect_to root_url
+  end
+end

app/controllers/users_controller.rb

@@ -11,6 +11,7 @@ class UsersController < ApplicationController
   def create 
     @user = User.new(user_params)
     if @user.save
+      log_in @user
       flash[:success] = 'Welcome to the Sample App!'
       redirect_to @user
       # redirect_to user_url(@user)

app/helpers/sessions_helper.rb

+# The
+module SessionsHelper
+  # Logs in the given user.
+  def log_in(user)
+    session[:user_id] = user.id
+  end
+
+  # Return the current logged-in user (if any).
+  def current_user
+    @current_user ||= User.find_by(id: session[:user_id])
+  end
+
+  # Returns true if the user is logged in, false otherwise. 
+  def logged_in?
+    !current_user.nil?
+  end
+end

app/models/user.rb

+# This
 class User < ApplicationRecord
   before_save  { self.email.downcase! }
   validates :name, presence: true, length: { maximum: 50 }
@@ -5,6 +6,13 @@ class User < ApplicationRecord
   validates :email, presence: true, length: { maximum: 255 },
             format: { with: VALID_EMAIL_REGEX },
             uniqueness: { case_sensitive: false }
-  validates :password, presence: true, length: {minimum: 6}         
+  validates :password, presence: true, length: {minimum: 6}
   has_secure_password
+
+  # Returns the hash digest of the given string. 
+  def User.digest(string)
+      cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST : 
+                                                    BCrypt::Engine.cost
+      BCrypt::Password.create(string, cost: cost)
+  end
 end

app/views/layouts/_header.html.erb

@@ -5,7 +5,24 @@
       <ul class="nav navbar-nav navbar-right">
         <li><%= link_to "Home",   root_path     %></li>
         <li><%= link_to "Help",   help_path     %></li>
-        <li><%= link_to "Login",  '#'           %></li>
+        <% if logged_in? %>
+          <li><% link_to 'Users', '#' %></li>
+          <li class="dropdown">
+            <a href='#' class="dropdown-toggle" data-toggle="dropdown">
+              Account <b class="caret"></b>
+            </a>
+            <ul class="dropdown-menu">
+              <li><%= link_to "Profile", current_user %></li>
+              <li><%= link_to "Settings", '#' %></li>
+              <li class="divider"></li>
+              <li>
+                <%= link_to "Log out", logout_path, method: :delete %>
+              </li>
+            </ul>
+          </li>
+        <% else %>
+          <li><%= link_to "Log in", login_path %></li>
+        <% end %>
       </ul>
     </nav>
   </div>

app/views/sessions/new.html.erb

+<% provide(:title, "Log in") %> 
+<h1>Log in</h1>
+
+<div class="row">
+  <div class="col-md-6 col-md-offset-3">
+    <%= form_for(:session, url: login_path) do |f| %>
+      <%= f.label :email %>
+      <%= f.email_field :email, class: 'form-control' %>
+
+      <%= f.label :password %>
+      <%= f.password_field :password, class: 'form-control' %>
+
+      <%= f.submit "Log in", class: "btn btn-primary" %>
+    <% end %>
+  
+    <p>New user? <%= link_to "Sign up now!", signup_path %></p>
+  </div>
+</div>

config/routes.rb

 Rails.application.routes.draw do
+
   root 'static_pages#home'
   get '/signup',    to: 'users#new'
   get '/help',      to: 'static_pages#help'
   get '/about',     to: 'static_pages#about'
   get '/contact',   to: 'static_pages#contact'
   post '/signup',   to: 'users#create'
+  get '/login',     to: 'sessions#new'
+  post '/login',    to: 'sessions#create'
+  delete '/logout', to: 'sessions#destroy'
   resources :users
 end

test/controllers/sessions_controller_test.rb

+require 'test_helper'
+
+class SessionsControllerTest < ActionDispatch::IntegrationTest
+  test "should get new" do
+    get login_path
+    assert_response :success
+  end
+
+end

test/fixtures/users.yml

 # Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+foo:
+  name: foo
+  email: foo@bar.com  
+  password_digest: <%= User.digest('password') %>

test/integration/site_layout_test.rb

@@ -12,6 +12,7 @@ class SiteLayoutTest < ActionDispatch::IntegrationTest
     assert_select   'a[href=?]', help_path
     assert_select   'a[href=?]', about_path
     assert_select   'a[href=?]', contact_path
+    assert_select   'a[href=?]', login_path
 
     get contact_path
     assert_select 'title', full_title('Contact')

test/integration/users_login_test.rb

+require 'test_helper'
+
+class UsersLoginTest < ActionDispatch::IntegrationTest
+  # comment
+  def setup
+    @user = users(:foo)
+  end
+
+  # comment
+  test 'login with invalid information' do
+    get login_path
+    assert_template 'sessions/new'
+    post login_path, params: { session: { email: '', password: '' } }
+    assert_template 'sessions/new'
+    assert_not flash.empty?
+    get root_path
+    assert flash.empty?
+  end
+
+  # comment
+  test 'login with valid information followed by logout' do
+    get login_path
+    post login_path, params: { session: { email: @user.email,
+                                          password: 'password' } }
+    assert is_logged_in?
+    assert_redirected_to @user
+    follow_redirect!
+    assert_template 'users/show'
+    assert_select 'a[href=?]', login_path, count: 0
+    assert_select 'a[href=?]', logout_path
+    assert_select 'a[href=?]', user_path(@user)
+    delete logout_path
+    assert_not is_logged_in?
+    assert_redirected_to root_url
+    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
+end

test/integration/users_signup_test.rb

@@ -27,5 +27,6 @@ class UsersSignupTest < ActionDispatch::IntegrationTest
     assert_template 'users/show'
     assert_not flash.empty?
     assert_select 'div.alert'
+    assert is_logged_in?
   end
 end

test/test_helper.rb

@@ -7,12 +7,15 @@ require 'rails/test_help'
 require "minitest/reporters"
 Minitest::Reporters.use!
 
-
-
+# comment
 class ActiveSupport::TestCase
   # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
   fixtures :all
 
   include ApplicationHelper
 
+  # Returns true if a test user is logged in.
+  def is_logged_in?
+      !session[:user_id].nil?
+  end
 end