rails_responder.rb

def create
  card_saver = Billing::SaveCreditCard.new(user: current_user, card: card_params)
  
  responder = respond do |r|
    r.success { render :success }
    r.failure { render :failure }
  end
  
  card_saver.call(responder)
end

rails_way.rb

def create
  card = current_user.credit_cards.create(card_params)
  if card.persisted?
    render :success
  else
    render :failure
  end
end

responder.rb

def create
  card_saver = Billing::SaveCreditCard.new(user: current_user, card: card_params)
  responder = SaveCardHandler.new(self)
  
  card_saver.call(responder)
end

class SaveCardHandler < SimpleDelegator
  def success
    render :success
  end
  def failure
    render :failure
  end
end

services_.rb

def create
  card = Billing::SaveCreditCard.new(user: current_user, card: card_params).call
  if card.persisted?
    render :success
  else
    render :failure
  end
end