Introduction

--devise is a gem that allows you to easily add authentication to your Rails application. devise is a wrapper for Rack middleware called warden, and the actual authentication is done by warden (so if you want to know the implementation details, first implement warden. I think I need to see it). --In the Rails tutorial, the authentication function is created by scratching, but in the actual Rails application, it seems that creating the authentication function using this devise is the de facto standard.

――This time, for my own study, I would like to organize how to use devise to add authentication function to Rails application. The content is almost the same as this article. Xie Xie

--All of the following implementations can be found in this repository.

environment

Ruby on Rails 5.2.4.3
Ruby 2.6.4

install devise

1. Edit Gemfile

# Devise
gem 'devise'

2.bundle install

$bundle install

devise settings

1. Execute the following command

$ rails g devise:install
      create  config/initializers/devise.rb
      create  config/locales/devise.en.yml
===============================================================================

Depending on your application's configuration some manual setup may be required:

  1. Ensure you have defined default url options in your environments files. Here
     is an example of default_url_options appropriate for a development environment
     in config/environments/development.rb:

       config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

     In production, :host should be set to the actual host of your application.

     * Required for all applications. *

  2. Ensure you have defined root_url to *something* in your config/routes.rb.
     For example:

       root to: "home#index"
     
     * Not required for API-only Applications *

  3. Ensure you have flash messages in app/views/layouts/application.html.erb.
     For example:

       <p class="notice"><%= notice %></p>
       <p class="alert"><%= alert %></p>

     * Not required for API-only Applications *

  4. You can copy Devise views (for customization) to your app by running:

       rails g devise:views
       
     * Not required *

===============================================================================

Set default URL

`config/development.rb`


Rails.application.configure do
  ~~Omission~~
  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
end

Create root page

You can skip this and set any page as the root page.


$rails g controller StaticPages index

`route.rb`


Rails.application.routes.draw do
  root 'static_pages#index'
  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
end

Set flash message

Edit app / views / layouts / application.html.erb

<!DOCTYPE html>
<html> 
 <head>
  <title>DeviseRails5</title>
  <%= csrf_meta_tags %>

  <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track': 'reload' %>
  <%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
 </head>
 <body>
  <p class="notice"><%= notice %></p>
  <p class="alert"><%= alert %></p>

  <%= yield %>

 </body> 
</html>

Create a devise view

$ rails g devise:views
invoke  Devise::Generators::SharedViewsGenerator
create    app/views/devise/shared
create    app/views/devise/shared/_error_messages.html.erb
create    app/views/devise/shared/_links.html.erb
invoke  form_for
create    app/views/devise/confirmations
create    app/views/devise/confirmations/new.html.erb
create    app/views/devise/passwords
create    app/views/devise/passwords/edit.html.erb
create    app/views/devise/passwords/new.html.erb
create    app/views/devise/registrations
create    app/views/devise/registrations/edit.html.erb
create    app/views/devise/registrations/new.html.erb
create    app/views/devise/sessions
create    app/views/devise/sessions/new.html.erb
create    app/views/devise/unlocks
create    app/views/devise/unlocks/new.html.erb
invoke  erb
create    app/views/devise/mailer
create    app/views/devise/mailer/confirmation_instructions.html.erb
create    app/views/devise/mailer/email_changed.html.erb
create    app/views/devise/mailer/password_change.html.erb
create    app/views/devise/mailer/reset_password_instructions.html.erb
create    app/views/devise/mailer/unlock_instructions.html.erb

Create User model

rails g devise User

The above command will generate the following migration files.

`db/migrate/20200622180124_devise_create_users.rb`


# frozen_string_literal: true

class DeviseCreateUsers < ActiveRecord::Migration[5.2]
  def change
    create_table :users do |t|
      ## Database authenticatable
      t.string :email,              null: false, default: ""
      t.string :encrypted_password, null: false, default: ""

      ## Recoverable
      t.string   :reset_password_token
      t.datetime :reset_password_sent_at

      ## Rememberable
      t.datetime :remember_created_at

      ## Trackable
      # t.integer  :sign_in_count, default: 0, null: false
      # t.datetime :current_sign_in_at
      # t.datetime :last_sign_in_at
      # t.inet     :current_sign_in_ip
      # t.inet     :last_sign_in_ip

      ## Confirmable
      # t.string   :confirmation_token
      # t.datetime :confirmed_at
      # t.datetime :confirmation_sent_at
      # t.string   :unconfirmed_email # Only if using reconfirmable

      ## Lockable
      # t.integer  :failed_attempts, default: 0, null: false # Only if lock strategy is :failed_attempts
      # t.string   :unlock_token # Only if unlock strategy is :email or :both
      # t.datetime :locked_at


      t.timestamps null: false
    end

    add_index :users, :email,                unique: true
    add_index :users, :reset_password_token, unique: true
    # add_index :users, :confirmation_token,   unique: true
    # add_index :users, :unlock_token,         unique: true
  end
end

It seems that database_authenticatable, registerable, recoverable, rememberable and validatable are turned on by default.

`app/models/user.rb`


class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable
end

This time, we will create it with the default, but you can optionally enable any of the 10 modules.

module	Overview
Database Authenticatable	Hash the password and store it in the database to verify the authenticity of the user during sign-in. Authentication can be done with both POST request or HTTP basic authentication.
Omniauthable	OmniAuth（https://github.com/omniauth/omniauth)Add support.
Confirmable	Send an email with verification instructions to see if your account has already been verified at sign-in.
Recoverable	Resets the user's password and sends a reset instruction.
Registerable	Process user sign-up through the registration process, allowing users to edit and destroy their account.
Rememberable	Manages the generation and clearing of tokens to remember users from stored cookies.
Trackable	Keep track of sign-ins, time stamps, and IP addresses..
Timeoutable	Expires sessions that have been inactive for the specified time period.
Validatable	Provides email and password verification. This is optional and customizable so you can define your own validation.
Lockable	Locks the account after the specified number of failed sign-in attempts. Can be unlocked by email or after a specified time period

Perform a migration

$ rake db:migrate

Edit View

Add header

app/views/layouts/application.html.erb

<!DOCTYPE html>
<html> 
 <head>
  <title>DeviseSampleApp</title>
  <%= csrf_meta_tags %>

  <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track': 'reload' %>
  <%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
 </head>
 <body>
 <header>
    <nav>
        <% if user_signed_in? %>
        <%= link_to 'Profile change', edit_user_registration_path %>
        <%= link_to 'Log out', destroy_user_session_path, method: :delete %>
    <% else %>
        <%= link_to 'Sign up', new_user_registration_path %>
        <%= link_to 'Login', new_user_session_path %>
        <% end %>
    </nav>
  </header>
  <p class="notice"><%= notice %></p>
  <p class="alert"><%= alert %></p>

  <%= yield %>

 </body> 
</html>

――When you access the top page, a screen like this is generated. スクリーンショット 2020-06-23 3.48.36.png

--Click sign up スクリーンショット 2020-06-23 3.34.51.png

――When you signed up and entered your email address and password, you were able to log in successfully! スクリーンショット 2020-06-23 3.35.29.png

Other

Helper methods provided by devise

user_signed_in?

You can check if the user is logged in.

current_user

You can access the logged-in user.

user_session

You can access the session.

Change redirect destination after signing up

`app/controllers/application_controller.rb`


class ApplicationController < ActionController::Base
  def after_sign_up_path_for(resource)
    edit_user_registration_path #You can edit here and jump to any page
  end
end

After signing up, I am now redirected to the following page.

スクリーンショット 2020-06-23 3.34.18.png

Change redirect destination after login

`app/controllers/application_controller.rb`


class ApplicationController < ActionController::Base
  def after_sign_in_path_for(resource)
    edit_user_registration_path #You can edit here and jump to any page
  end
end

Callback function

(I'm not sure exactly here)

--It seems that after_fetch is the only callback that devise calls (citation needed), so if you want to call other callbacks, use warden interface. Must be called directly.

References

heartcombo/devise
wardencommunity/warden
https://qiita.com/cigalecigales/items/f4274088f20832252374
https://qiita.com/Hal_mai/items/350c400e8763ce0487a3
https://stackoverflow.com/questions/11409828/does-devise-have-callback

Create authentication function in Rails application using devise

Introduction

environment

install devise

1. Edit Gemfile

devise settings

1. Execute the following command

Set default URL

config/development.rb

Create root page

route.rb

Set flash message

Edit app / views / layouts / application.html.erb

Create a devise view

Create User model

db/migrate/20200622180124_devise_create_users.rb

app/models/user.rb

Perform a migration

Edit View

Add header

Other

Helper methods provided by devise

Change redirect destination after signing up

app/controllers/application_controller.rb

Change redirect destination after login

app/controllers/application_controller.rb

Callback function

(I'm not sure exactly here)

References

`config/development.rb`

`route.rb`

`db/migrate/20200622180124_devise_create_users.rb`

`app/models/user.rb`

`app/controllers/application_controller.rb`

`app/controllers/application_controller.rb`