promisepreston

# app/services/authorize_api_request.rb

class AuthorizeApiRequest

  def initialize(headers = {})
    @headers = headers
  end

  def call
    { user: user }

promisepreston

# app/services/authenticate_user.rb

class AuthenticateUser
  def initialize(email, password)
    @email = email
    @password = password
  end

  def call
    JsonWebToken.encode(user_id: user.id) if user

promisepreston

# config/locales/en.yml

en:
  activemodel:
    errors:
      models:
        authenticate_user:
          failure: Wrong email or password

promisepreston

# define a command class
class AuthenticateUser
  # put SimpleCommand before the class' ancestors chain
  prepend SimpleCommand
  include ActiveModel::Validations

  # optional, initialize the command with some arguments
  def initialize(email, password)
    @email = email
    @password = password

promisepreston

# config/application.rb

module ApiApp
  class Application < Rails::Application
    #.....
    config.eager_load_paths << Rails.root.join('lib')
    #.....
  end
end

promisepreston

# lib/json_web_token.rb

class JsonWebToken
  HMAC_SECRET = Rails.application.secrets.secret_key_base

  def self.encode(payload, exp = 24.hours.from_now)
    payload[:exp] = exp.to_i
    JWT.encode(payload, HMAC_SECRET)
  end

promisepreston

<code data-gist-id="ec8cc541c45705a34988c68225627ecb" data-gist-hide-line-numbers="true"></code>
class UsersController < ApplicationController
  def show
    @user = User.find(params[:id])
  end

  def new
    @user = User.new
  end