8.1 -> 8.2.3

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

@@ -2,4 +2,5 @@ class ApplicationController < ActionController::Base
   # Prevent CSRF attacks by raising an exception.
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception
+  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])
+      # Sign the user in and redirect to the user's show page.
+      sign_in user
+      redirect_to user
+    else
+      flash.now[:error] = 'Invalid email/password combination' # Not quite right!
+      render 'new'
+    end
+  end
+
+  def destroy
+  end
+end

app/helpers/sessions_helper.rb

+module SessionsHelper
+  def sign_in(user)
+    remember_token = User.new_remember_token
+    cookies.permanent[:remember_token] = remember_token
+    user.update_attribute(:remember_token, User.digest(remember_token))
+    self.current_user = user
+  end
+
+  def signed_in?
+    !current_user.nil?
+  end
+  
+  def current_user=(user)
+    @current_user = user
+  end
+
+  def current_user
+    remember_token = User.digest(cookies[:remember_token])
+    @current_user ||= User.find_by(remember_token: remember_token)
+  end
+end

app/models/user.rb

@@ -4,5 +4,20 @@ class User < ActiveRecord::Base
   validates :email, presence: true, format: { with: VALID_EMAIL_REGEX }, uniqueness: { case_sensitive: false }
   validates :password, length: { minimum: 6 }
   before_save { self.email = email.downcase }
+  before_create :create_remember_token
   has_secure_password
+
+  def User.new_remember_token
+    SecureRandom.urlsafe_base64
+  end
+
+  def User.digest(token)
+    Digest::SHA1.hexdigest(token.to_s)
+  end
+
+  private
+
+  def create_remember_token
+    self.remember_token = User.digest(User.new_remember_token)
+  end
 end

app/views/layouts/_header.html.erb

@@ -6,7 +6,7 @@
         <ul class="nav pull-right">
           <li><%= link_to "Home", home_path %></li>
           <li><%= link_to "Help", help_path %></li>
-          <li><%= link_to "Sign in", '#' %></li>
+          <li><%= link_to "Sign in", signin_path %></li>
         </ul>
       </nav>
     </div>

app/views/sessions/new.html.erb

+<% provide(:title, "Sign in") %>
+<h1>Sign in</h1>
+
+<div class="row">
+  <div class="span6 offset3">
+    <%= form_for(:session, url: sessions_path) do |f| %>
+
+      <%= f.label :email %>
+      <%= f.text_field :email %>
+
+      <%= f.label :password %>
+      <%= f.password_field :password %>
+
+      <%= f.submit "Sign in", class: "btn btn-large btn-primary" %>
+    <% end %>
+
+    <p>New user? <%= link_to "Sign up now!", signup_path %></p>
+  </div>
+</div>
\ No newline at end of file

config/routes.rb

@@ -7,5 +7,8 @@ Rails.application.routes.draw do
   get '/about', to: 'static_pages#about'
   get '/contact', to: 'static_pages#contact'
   get '/signup', to: 'users#new'
+  get '/signin', to: 'sessions#new'
+  delete '/signout', to: 'sessions#destroy'
   resources :users
+  resources :sessions, only: [:new, :create, :destroy]
 end

db/migrate/20200702072601_add_remember_token_to_users.rb

+class AddRememberTokenToUsers < ActiveRecord::Migration
+  def change
+    add_column :users, :remember_token, :string
+    add_index :users, :remember_token
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20200630043304) do
+ActiveRecord::Schema.define(version: 20200702072601) do
 
   create_table "users", force: :cascade do |t|
     t.string   "name"
@@ -19,8 +19,10 @@ ActiveRecord::Schema.define(version: 20200630043304) do
     t.datetime "created_at",      null: false
     t.datetime "updated_at",      null: false
     t.string   "password_digest"
+    t.string   "remember_token"
   end
 
   add_index "users", ["email"], name: "index_users_on_email", unique: true
+  add_index "users", ["remember_token"], name: "index_users_on_remember_token"
 
 end

spec/models/user_spec.rb

@@ -93,4 +93,12 @@ describe User do
     before { @user.password = @user.password_confirmation = "a" * 5 }
     it { should be_invalid }
   end
+  it { should respond_to(:password_confirmation) }
+  it { should respond_to(:remember_token) }
+  it { should respond_to(:authenticate) }
+
+  describe "remember token" do
+    before { @user.save }
+    its(:remember_token) { should_not be_blank }
+  end
 end

spec/requests/authentication_pages_spec.rb

+require 'spec_helper'
+
+describe "AuthenticationPages" do
+  subject { page }
+
+  describe "signin page" do
+    before { visit signin_path }
+    it { should have_content('Sign in') }
+    it { should have_title('Sign in') }
+  end
+
+  describe "signin" do
+    before { visit signin_path }
+
+    describe "with invalid information" do
+      before { click_button "Sign in" }
+
+      it { should have_title('Sign in') }
+      it { should have_selector('div.alert.alert-error') }
+
+      describe "after visiting another page" do
+        before { click_link "Home" }
+        it { should_not have_selector('div.alert.alert-error') }
+      end
+    end
+
+    describe "with valid information" do
+      let(:user) { FactoryGirl.create(:user) }
+      before do
+        fill_in "Email",    with: user.email.upcase
+        fill_in "Password", with: user.password
+        click_button "Sign in"
+      end
+
+      it { should have_title(user.name) }
+      it { should have_link('Profile',     href: user_path(user)) }
+      it { should have_link('Sign out',    href: signout_path) }
+      it { should_not have_link('Sign in', href: signin_path) }
+    end
+  end
+end