Overview

Sample project to implement service object that handle authentication.

Specs

User
  valid with username, password and password_confirmation
  is invalid without username
  is invalid without password

Authentication API
  User sign in
    valid credential
      return token
    invalid credential
      return error response

Dashboard API
  User visit dashboard page
    authenticated user
      return success response
    unauthenticated user
      return errors response
    uncorrect format auth header
      return's errros response
    uncorrect auth token
      return's error response

Enpoints

Sign in

• URL
  • POST /auth
• PARAMS
  • { auth: {username: "username", password: "password" } }
• Success Response
  • { jwt: "auth_token_here" }
• Error Response
  • { error: { message: "Sorry, the credential is invalid" } }

Dashboard

• URL
  • GET /dashboard
• PARAMS
  • none
• Success Response
  • {success: {message: "Welcome to dashboard, #{username}}
• Error Response
  • {error: {message: "Sorry, you're not authenticated"}}

Highlight Source Code

Authentication Service

-> app/services/auth_service.rb

class AuthService 
  attr_accessor :token, :user

  def initialize(options)
    @username = options[:username]
    @password = options[:password]
    @token = options[:token]
    @auth_header = options[:auth_header]

    setup
  end

  def setup
    @token = @auth_header.split[1] if auth_header_valid?

    set_token if @token.nil?
    set_user if @token
  end

  def auth_header_valid?
    return false unless @auth_header
    auth_header_arr = @auth_header.split
    return false if auth_header_arr.count != 2 
    return false if auth_header_arr[0] != "Bearer"
    true
  end

  private
  def set_token 
    @token = TokenService.generate(user_id: @user.id) if allow?
  end

  def set_user 
    @user = User.find_by(id: TokenService.new(token: @token).user_id)
  end

  def allow?
    @user = User.find_by(username: @username)
    if @user and @user.authenticate(@password)
      true
    else 
      false
    end
  end
end

Token Service

-> app/services/token_service.rb

class TokenService
  attr_accessor :token
  
  def initialize(options)
    @token = options[:token]
  end

  def self.generate(payload)
    JWT.encode(payload, nil, 'none')
  end

  def decode
    begin
      JWT.decode(@token, nil, false)
    rescue
      nil 
    end
  end

  def payload 
    decode[0] if decode
  end

  def user_id
    payload["user_id"]
  end
end

Authentication Controller

-> app/controllers/auth_controller.rb

class AuthController < ApplicationController
  before_action :set_auth, only: [:create]

  def create
    if @auth.token
      render json: { jwt: @auth.token }
    else
      render json: { error: {message: "Sorry, the credential is invalid"} }
    end
  end

  private 
  def auth_params 
    params.require(:auth).permit(:username, :password)
  end

  def set_auth
    @auth = AuthService.new(auth_params)
  end
end

Dashboard Controller

-> app/controllers/dashboard_controller.rb

class DashboardController < ApplicationController
  before_action :set_auth, only: [:index]

  def index
    if @auth.auth_header_valid?
      render json: { success: { message: "Welcome to dashboard, #{@auth.user.username}" } } 
    else 
      render json: { error: { message: "Sorry, you're not authenticated" } }
    end
  end

  private 
  def set_auth
    @auth = AuthService.new(auth_header: request.authorization)
  end
end

License

Copyright 2018 Philip Lambok