Devise authenticate_user_from_token

Api controller

class ApplicationController < ActionController::API
  before_action :authenticate_user_from_token!

  def authenticate_user_from_token!
    auth_token = request.headers['Authorization']
    auth_token ? authenticate_with_token!(auth_token) : authentication_error
  end

  def authenticate_with_token!(token)
    unless token.include?(':')
      authentication_error
      return
    end
    user_id  = token.split(':').first
    user = User.where(id: user_id).first
    if user && Devise.secure_compare(user.authentication_token, token)
      sign_in user, store: false
    else
      authentication_error
    end
  end

  def authentication_error
    render json: {error: 'unauthorized'}, status: :unauthorized
  end

  private :authenticate_with_token!
end