libr-2/app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  include ActionController::Serialization

  serialization_scope :view_context
  before_action :current_user!

  def current_user!
    @current_user = nil
    @current_user = current_user if user_signed_in?
  end

  def user_json(user= current_user)
    {
      user: {
        id: user.id,
        name: user.name,
        email: user.email,
        token: JWT.encode({token: user.active_auth_token}, user.email)
      }
    }
  end

  def authenticate_user_from_token
    auth_token = AuthToken.find_by(value: request.headers["Authorization"].try(:split, ' ').try(:last))
    if auth_token
      @current_user = auth_token.user
    else
      return render json: {message: 'Token is not valid'}, status: 401
    end
  end
end