Agile Web Development with Rails, Edition 4

14.2 Iteration I2: Authenticating Users 13.3 Playtime

14.1 Iteration I1: Adding Users

Scaffold the user model

rails generate scaffold User name:string hashed_password:string salt:string
      invoke  active_record
      create    db/migrate/20140204204331_create_users.rb
      create    app/models/user.rb
      invoke    test_unit
      create      test/unit/user_test.rb
      create      test/fixtures/users.yml
       route  resources :users
      invoke  scaffold_controller
      create    app/controllers/users_controller.rb
      invoke    erb
      create      app/views/users
      create      app/views/users/index.html.erb
      create      app/views/users/edit.html.erb
      create      app/views/users/show.html.erb
      create      app/views/users/new.html.erb
      create      app/views/users/_form.html.erb
      invoke    test_unit
      create      test/functional/users_controller_test.rb
      invoke    helper
      create      app/helpers/users_helper.rb
      invoke      test_unit
      create        test/unit/helpers/users_helper_test.rb
      invoke  stylesheets
   identical    public/stylesheets/scaffold.css

Run the migration

rake db:migrate
mv 20140204204331_create_users.rb 20140204000009_create_users.rb
==  CreateUsers: migrating ====================================================
-- create_table(:users)
   -> 0.0010s
==  CreateUsers: migrated (0.0010s) ===========================================
 

Add validation, has_secure_password

edit app/models/user.rb
require 'digest/sha2'
 
class User < ActiveRecord::Base
  validates :name, presence: true, uniqueness: true
 
  validates :password, confirmation: true
  attr_accessor :password_confirmation
  attr_reader   :password
 
  validate  :password_must_be_present
  
  def User.authenticate(name, password)
    if user = find_by_name(name)
      if user.hashed_password == encrypt_password(password, user.salt)
        user
      end
    end
  end
 
  def User.encrypt_password(password, salt)
    Digest::SHA2.hexdigest(password + "wibble" + salt)
  end
  
  # 'password' is a virtual attribute
  def password=(password)
    @password = password
 
    if password.present?
      generate_salt
      self.hashed_password = self.class.encrypt_password(password, salt)
    end
  end
  
  private
 
    def password_must_be_present
      errors.add(:password, "Missing password") unless hashed_password.present?
    end
  
    def generate_salt
      self.salt = self.object_id.to_s + rand.to_s
    end
end

Avoid redirect after create, update operations

edit app/controllers/users_controller.rb
  def create
    @user = User.new(params[:user])
 
    respond_to do |format|
      if @user.save
        format.html { redirect_to(users_url,
          :notice => "User #{@user.name} was successfully created.") }
        format.xml  { render :xml => @user,
          :status => :created, :location => @user }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @user.errors,
          :status => :unprocessable_entity }
      end
    end
  end
edit app/controllers/users_controller.rb
  def update
    @user = User.find(params[:id])
 
    respond_to do |format|
      if @user.update_attributes(params[:user])
        format.html { redirect_to(users_url,
          :notice => "User #{@user.name} was successfully updated.") }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @user.errors,
          :status => :unprocessable_entity }
      end
    end
  end

Display users sorted by name

edit app/controllers/users_controller.rb
  def index
    @users = User.order(:name)
 
    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @users }
    end
  end

Add Notice

edit app/views/users/index.html.erb
<h1>Listing users</h1>
<% if notice %>
<p id="notice"><%= notice %></p>
<% end %>
 
<table>
  <tr>
    <th>Name</th>
    <th></th>
    <th></th>
    <th></th>
  </tr>
 
<% @users.each do |user| %>
  <tr>
    <td><%= user.name %></td>
    <td><%= link_to 'Show', user %></td>
    <td><%= link_to 'Edit', edit_user_path(user) %></td>
    <td><%= link_to 'Destroy', user, :confirm => 'Are you sure?', :method => :delete %></td>
  </tr>
<% end %>
</table>
 
<br />
 
<%= link_to 'New User', new_user_path %>

Update form used to both create and update users

edit app/views/users/_form.html.erb
<div class="depot_form">
 
<%= form_for @user do |f| %>
  <% if @user.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@user.errors.count, "error") %>
        prohibited this user from being saved:</h2>
      <ul>
      <% @user.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
 
  <fieldset>
  <legend>Enter User Details</legend>
 
  <div class="field">
    <%= f.label :name, 'Name:' %>
    <%= f.text_field :name, size: 40 %>
  </div>
 
  <div class="field">
    <%= f.label :password, 'Password:' %>
    <%= f.password_field :password, size: 40 %>
  </div>
 
  <div class="field">
    <%= f.label :password_confirmation, 'Confirm:' %>
    <%= f.password_field :password_confirmation, size: 40 %>
  </div>
 
  <div class="actions">
    <%= f.submit %>
  </div>
 
  </fieldset>
<% end %>
 
</div>

Demonstrate creating a new user

get /users

Listing users

Name

New User
get /users/new

New user

Enter User Details
Back
post /users
You are being redirected.
get http://localhost:3000/users

Listing users

User dave was successfully created.

Name
dave Show Edit Destroy

New User

Show how this is stored in the database

sqlite3> select * from users
             id = 1
           name = dave
hashed_password = af2e0eb422fe05515f269c644a30836cb83318f03d28a2a66372324305303ac4
           salt = 699938823854200.6006759627655528
     created_at = 2014-02-04 20:43:33.970461
     updated_at = 2014-02-04 20:43:33.970461

Update tests to reflect the changes in redirection and uniqueness

edit test/functional/users_controller_test.rb
require 'test_helper'
 
class UsersControllerTest < ActionController::TestCase
  setup do
    @input_attributes = {
      name:                  "sam",
      password:              "private",
      password_confirmation: "private"
    }
 
    @user = users(:one)
  end
  #...
  test "should create user" do
    assert_difference('User.count') do
      post :create, user: @input_attributes
    end
 
    assert_redirected_to users_path
  end
  #...
  test "should update user" do
    put :update, id: @user.to_param, user: @input_attributes
    assert_redirected_to users_path
  end
end

Make sure that all test names are unique

edit test/fixtures/users.yml
<% SALT = "NaCl" unless defined?(SALT) %>
 
one:
  name: dave
  hashed_password: <%= User.encrypt_password('secret', SALT) %>
  salt: <%= SALT %>
 
two:
  name: MyString
  hashed_password: MyString
  salt: MyString
rake test
Loaded suite /home/rubys/.rvm/gems/ruby-1.9.2-p320/gems/rake-10.1.1/lib/rake/rake_test_loader
Started
[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
..........
Finished in 0.338151 seconds.
 
10 tests, 31 assertions, 0 failures, 0 errors, 0 skips
 
Test run options: --seed 61807
Loaded suite /home/rubys/.rvm/gems/ruby-1.9.2-p320/gems/rake-10.1.1/lib/rake/rake_test_loader
Started
[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
..........................................
Finished in 0.928265 seconds.
 
42 tests, 73 assertions, 0 failures, 0 errors, 0 skips
 
Test run options: --seed 57176
[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
Loaded suite /home/rubys/.rvm/gems/ruby-1.9.2-p320/gems/rake-10.1.1/lib/rake/rake_test_loader
Started
...
Finished in 0.741761 seconds.
 
3 tests, 47 assertions, 0 failures, 0 errors, 0 skips
 
Test run options: --seed 56610

14.2 Iteration I2: Authenticating Users 13.3 Playtime