Implement basic login

app/assets/javascripts/application.js

@@ -12,5 +12,6 @@
 //
 //= require jquery
 //= require jquery_ujs
+//= require bootstrap
 //= require turbolinks
 //= require_tree .

app/assets/javascripts/sessions.coffee

@@ -0,0 +1,3 @@
+# 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

@@ -0,0 +1,3 @@
+// 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

@@ -1,6 +1,8 @@
 class ApplicationController < ActionController::Base
   protect_from_forgery with: :exception
 
+  include SessionsHelper
+
   def hello
   	render html: "hello, world"
   end

app/controllers/sessions_controller.rb

@@ -0,0 +1,20 @@
+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_in user
+  		redirect_to user
+  	else
+  		flash.now[:danger] = 'Invalid email/password combination'
+  		render 'new' 
+  	end
+  end
+
+  def destroy
+    log_out
+    redirect_to root_path
+  end
+end

app/controllers/users_controller.rb

@@ -10,6 +10,7 @@ def show
   def create
   	@user = User.new(user_params)
   	if @user.save
+      log_in @user
       flash[:success] = "Welcome to the Sample App!"
       redirect_to @user
   	else

app/helpers/sessions_helper.rb

@@ -0,0 +1,18 @@
+module SessionsHelper
+	def log_in(user)
+		session[:user_id] = user.id
+	end
+
+	def log_out
+		session.delete(:user_id)
+		@current_user = nil
+	end
+
+	def current_user
+		@current_user ||= User.find_by(id: session[:user_id]) 
+	end
+
+	def logged_in?
+		!current_user.nil?
+	end
+end

app/models/user.rb

@@ -7,4 +7,10 @@ class User < ApplicationRecord
 		format: { with: VALID_EMAIL_REGEX },
 		uniqueness: { case_sensitive: false }
 	has_secure_password
+
+	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 +5,23 @@
 			<ul class="nav navbar-nav navbar-right">
 				<li><%= link_to "Home", root_path %></li>
 				<li><%= link_to "Help", help_path %></li>
-				<li><%= link_to "Log in", '#' %></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 "Setting", '#' %></li>
+							<li class="divider"></li>
+							<li>
+								<%= link_to "Log out", logout_path %>
+							</li>
+						</ul>
+					</li>
+				<% else %>
+					<li><%= link_to "Log in", login_path %></li>
+				<% end %>
 			</ul>
 		</nav>
 	</div>

app/views/sessions/new.html.erb

@@ -0,0 +1,20 @@
+<% 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> </p>
+		<p>New User? <%= link_to "Sign up now!", signup_path %></p>
+	</div>
+</div>

config/routes.rb

@@ -1,5 +1,7 @@
 Rails.application.routes.draw do
 
+  get 'sessions/new'
+
   get '/signup', to: 'users#new'
 
   get '/help', to: 'static_pages#help'
@@ -9,6 +11,12 @@
   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'
 
   # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
   root 'static_pages#home'

test/controllers/sessions_controller_test.rb

@@ -0,0 +1,9 @@
+require 'test_helper'
+
+class SessionsControllerTest < ActionDispatch::IntegrationTest
+  test "should get new" do
+    get sessions_new_url
+    assert_response :success
+  end
+
+end

test/fixtures/users.yml

@@ -1 +1,5 @@
 # Read about fixtures at http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+michael:
+  name: Michael Example
+  email: michael@example.com
+  password_digest: <%= User.digest('password') %>

test/integration/users_login_test.rb

@@ -0,0 +1,40 @@
+require 'test_helper'
+
+class UsersLoginTest < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+  def setup
+    @user = users(:michael)
+  end
+
+  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
+
+  test "login with valid information 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_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
+end

test/integration/users_signup_test.rb

@@ -25,6 +25,7 @@ class UsersSignupTest < ActionDispatch::IntegrationTest
   	end
   	follow_redirect!
   	assert_template 'users/show'
-  	assert_not flash.blank?
+  	assert_not flash.empty?
+    assert is_logged_in?
   end
 end

test/test_helper.rb

@@ -9,5 +9,9 @@ class ActiveSupport::TestCase
   fixtures :all
   include ApplicationHelper
 
+  def is_logged_in?
+  	!session[:user_id].nil?
+  end
+
   # Add more helper methods to be used by all tests here...
 end