[RUBY] Implement login function in Rails simply by name and password (1)

Introduction

Implement it more simply than the email and password login used in the rails tutorial. Do not use gems such as devise.

Premise

Basic rails knowledge to the extent that you have completed the rails tutorial
Mac
Ruby on Rails6
Test omitted

Target

Here, log in using the name and password of the Room table.

procedure

First, create a model to log in. This time the Room table

MacBook % rails g model Room name:string

Add to the generated migration file and apply migration
This will prevent empty names from being saved in the database

`db/migrate/Time stamp.create_rooms.rb`


class CreateRooms < ActiveRecord::Migration[6.0]
  def change
    create_table :rooms do |t|
      t.string :name, null: false

      t.timestamps
    end
  end
end

MacBook % rails db:migrate

Add has_secure_password method to Room.rb

`app/models/room.rb`


class Room < ApplicationRecord
  validates :name, presence: true, length: { maximum: 50 }
  has_secure_password
end

--Create a migration to add the password_digest column and apply the migration

MacBook % rails generate migration add_password_digest_to_rooms password_digest:string

MacBook % rails db:migrate

--Open Gemfile, uncomment gem'bcrypt' and install

`Gemfile`


~
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'
~

--Additionally limit empty password and minimum number of characters

`app/models/room.rb`


class Room < ApplicationRecord
  validates :name, presence: true, length: { maximum: 50 }
  has_secure_password
  validates :password, presence: true, length: { minimum: 6 }
end

--Check if the instance can be created and saved in the database with Rails console

`A terminal different from the one that started the server`


MacBook % rails c  
~
irb(main):001:0> @room = Room.new(name:"tokyoroom",password:"password",password_confirmation:"password")
   (2.2ms)  SET NAMES utf8mb4,  @@SESSION.sql_mode = CONCAT(CONCAT(@@sql_mode, ',STRICT_ALL_TABLES'), ',NO_AUTO_VALUE_ON_ZERO'),  @@SESSION.sql_auto_is_null = 0, @@SESSION.wait_timeout = 2147483
=> #<Room id: nil, name: "tokyoroom", created_at: nil, updated_at: nil, password_digest: [FILTERED]>
irb(main):002:0> @room.save
   (0.7ms)  BEGIN
  Room Create (3.3ms)  INSERT INTO `rooms` (`name`, `created_at`, `updated_at`, `password_digest`) VALUES ('tokyoroom', '2020-09-23 07:26:30.787094', '2020-09-23 07:26:30.787094', '$2a$12$SmCtpmRZn0M5BMtuT6BmAOKO.DMAmMOIYSXoHlxDrSbA2AQcAYnMC')
   (5.0ms)  COMMIT
=> true