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dependency_injection_service_objects

🛠 Dependency Injection for Service Objects in Controllers​

Promote testability by injecting service dependencies into controllers rather than hard‐coding them. Use controller attributes or initializer injection to swap implementations during tests or compose different behaviors.

class OrdersController < ApplicationController
  def initialize(order_creator: OrderCreator.new)
    @order_creator = order_creator
    super()
  end

  def create
    order = @order_creator.call(order_params)
    render json: order, status: :created
  end

  private

  def order_params
    params.require(:order).permit(:product_id, :quantity)
  end
end

# In tests
OrdersController.new(order_creator: MockOrderCreator.new)