Đường Sỹ Hoàng · @hoangds · Van Hau Le · Đường Sỹ Hoàng · Son Do Hong · Đường Sỹ Hoàng
--- a/app/helpers/sessions_helper.rb 0 → 100644
+++ b/app/helpers/sessions_helper.rb 0 → 100644
+module SessionsHelper
+  # Logs in the given user. 
+  def log_in(user)
+    session[:user_id] = user.id 
+  end
+  # Returns the current logged-in user (if any)
+  def current_user
+    if session[ :user_id]
+      @current_user ||= User.find_by( id: session[ :user_id])
+    end
+  end
+
+  # Return true if the user is logged in, false otherwise . 
+  def logged_in?
+    !current_user.nil?
--- a/app/controllers/sessions_controller.rb 0 → 100644
+++ b/app/controllers/sessions_controller.rb 0 → 100644
+class SessionsController < ApplicationController
+  def new
+  end
+
+  def create
+    user = User.find_by( email: params[ :session ][ :email ].downcase )
--- a/app/models/user.rb
+++ b/app/models/user.rb
 class User < ApplicationRecord
+  def User.digest(string)
+    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
+    BCrypt::Engine.cost
--- a/app/models/user.rb
+++ b/app/models/user.rb
 class User < ApplicationRecord
+  def User.digest(string)
+    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
+    BCrypt::Engine.cost
+    BCrypt::Password.create(string, cost: cost)
+  end
+
+# Constant
--- a/app/models/user.rb
+++ b/app/models/user.rb
 class User < ApplicationRecord
+  def User.digest(string)
--- a/app/views/layouts/_header.html.erb
+++ b/app/views/layouts/_header.html.erb
      <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>
--- a/test/controllers/sessions_controller_test.rb 0 → 100644
+++ b/test/controllers/sessions_controller_test.rb 0 → 100644
+require "test_helper"
+
+class SessionsControllerTest < ActionDispatch::IntegrationTest
+
--- a/test/integration/user_signup_test.rb → test/integration/users_signup_test.rb
+++ b/test/integration/user_signup_test.rb → test/integration/users_signup_test.rb
    end
    follow_redirect!
    assert_template "users/show" 
-    assert_not flash.empty?
--- a/app/helpers/sessions_helper.rb 0 → 100644
+++ b/app/helpers/sessions_helper.rb 0 → 100644
+  end
+  # Returns the current logged-in user (if any)
+  def current_user
+    if session[ :user_id]
+      @current_user ||= User.find_by( id: session[ :user_id])
+    end
+  end
+
+  # Return true if the user is logged in, false otherwise . 
+  def logged_in?
+   current_user.present?
+  end
+
+  # Logs out the current user
+  def log_out
+    session.delete( :user_id )
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
 class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
-   def hello
+  include SessionsHelper
+   
+  def hello