Question

我有一个从php codebase移植的rails应用程序。我有一个很长的控制器方法，基本上根据我的购物车中的项目计算总价。这是一种直接从php代码移植的遗留方法。

def total
    order = @cart.get_or_create_order
    order_contents = order_contents_for(order)

    discounts = {
      events: {},
      subjects: {},
      products: {}
    }

    adjusted_pricing = {}
    free = false
    shipping = 0
    total = 0

    # Logic for computing shipping price

    # Construct discount hash

    order_contents.each do |item|
       if (item.variant_price.present?)
         price = item.variant_price
       end
       else
         price = item.price
       end

       price_adjustments = {}
       popped_from = []

       # it's the issue due to legacy database structure,
       # product_id, subject_id and event_id is each column in
       # the database
       if (discounts[:products][item.product_id])
          price_adjustments = discounts[:products][item.product_id]
          discounts[:products].delete(item.product_id)
          popped_from = [:products, item.product_id]
       elsif (discounts[:subjects][item.subject_id])
          price_adjustments = discounts[:subjects][item.subject_id]
          discounts[:subjects].delete(item.subject_id)
          popped_from = [:subjects, item.subject_id]
       elsif (discounts[:events][item.event_id])
          price_adjustments = discounts[:events][item.event_id]
          discounts[:events].delete(item.event_id)
          popped_from = [:events, item.event_id]
       end

       if (adjustment = price_adjustments['$'])
          adjusted_price = price + adjustment
       elsif (adjustment = price_adjustments['%'])
          adjusted_price = price + price * (adjustment / 100.0)
          discounts[popped_from[0]][popped_from[1]] = price_adjustments
       else
          adjusted_price = price
       end

       adjusted_pricing[item.product_id] = {price: adjusted_price, discount: price - adjusted_price}

       total += adjusted_price
    end

    total += shipping
end

上面的代码是一个方法的巨大代码片段，所以我试图重构它并将其移动到模型price_calculator。

def calculate_total_for(order)
  order_contents = order.current_order_contents
  product_adjustments = order.product_adjustments

  shipping = calculate_shipping_price(order_contents, product_adjustments)

  discounts = construct_discount_hash(product_adjustments)

  adjusted_pricing = construct_adjusted_price_hash(discounts, order_contents)

  total_price = adjusted_pricing.inject(0) { |total, (k, v)| total + v[:price] }

  {
    total_price: total_price + shipping,
    shipping: shipping,
    adjusted_pricing: adjusted_pricing
  }
end

我基本上做了什么，仍在将上一个巨大的方法移动到它自己的类中，并将逻辑拆分为该类中的一个单独的私有方法，如calculate_shipping_price，construct_discount_hash。

我知道这远远不是一个好的代码。将其分解为私有方法，在可读性方面很好，但我开始觉得很难对它进行测试。希望有人可以提供建议或指导，在ruby中重构上述代码的最佳方法是什么。

PS：我是ruby / rails的新手，我之前使用的是C＃/ Javascript代码，因此有一些成语或者ruby-way来处理我不熟悉的事情。

Answer 1

对于您提到的示例，我会使用Extract Class from Method重构并使用Service Object而不是移动模型中的所有内容。

以下是对如何操作的概述，当然我为您留下了实现：

class Test
  def total
    order = @cart.get_or_create_order
    order_contents = order_contents_for(order)

    discounts = {
      events: {},
      subjects: {},
      products: {}
    }

    service = CalculateTotal.new(order, order_contents, discounts)

    if service.success?
      # Success logic
    else
      flash[:error] = service.error
      # Failure logic
    end
  end
end

class CalculateTotal
  attr_reader :success, :error

  def initialize(order, order_contents, discounts)
    @order = order
    @order_contents = order_contents
    @discounts = discounts
  end

  def call
    sum_orders + adjusted_prices + shipping
  end

  def success?
    !@error
  end

  private

  def sum_orders
    # Logic

    if something_fails
      @error = 'There was an error calculating the price'
    end

    # Logic
  end

  def adjusted_prices
    # Logic
  end

  def shipping
    # Logic
  end
end

将大型控制器方法重构为模型

1 个答案: