Ruby on rails Rails模型法中的无限循环

用例

def fill_once
  unless self.box_filled?
    # Get a random product from the user's recommendations
    product = self.subscription.user.recommended_product_records[rand(self.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless self.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        product.add_to_box_credits(self.subscription, "sample")
      else
        unless product.full_price_credits.nil?
          product.add_to_box_credits(self.subscription, "full")
        end
      end
      self.save!
    end
    self.fill_once # Here's the recursion
  end
end

如果用户没有在他们的箱子里装满他们的信用限额（默认为6）以内的产品，则会在箱子模型上调用一个方法，为他们装满产品

代码指南

def fill_once
  unless self.box_filled?
    # Get a random product from the user's recommendations
    product = self.subscription.user.recommended_product_records[rand(self.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless self.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        product.add_to_box_credits(self.subscription, "sample")
      else
        unless product.full_price_credits.nil?
          product.add_to_box_credits(self.subscription, "full")
        end
      end
      self.save!
    end
    self.fill_once # Here's the recursion
  end
end

框中的信用数由

box\u credits

给出，它循环遍历框中的所有产品并返回它们的总值。这似乎奏效了

布尔方法

box\u filled？

检查

box\u积分

方法是否等于或大于可用积分数（订阅积分）

fill\u once

方法应将产品添加到盒子中，直到盒子被填满（

box\u filled？

返回

true

）。当

box\u学分

等于可用学分数时，会发生这种情况

代码

def fill_once
  unless self.box_filled?
    # Get a random product from the user's recommendations
    product = self.subscription.user.recommended_product_records[rand(self.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless self.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        product.add_to_box_credits(self.subscription, "sample")
      else
        unless product.full_price_credits.nil?
          product.add_to_box_credits(self.subscription, "full")
        end
      end
      self.save!
    end
    self.fill_once # Here's the recursion
  end
end

box\u filled？

方法如下所示：

def box_filled?
  subscription = self.subscription
  if self.box_credits >= subscription.credits
    return true
  else
    return false
  end
end

box\u积分

由以下方法确定：

def box_credits
  count = 0
  unless self.added_product_hashes.nil?
    # Takes product hashes in the form {id, size, method}
    self.added_product_hashes.each do |product_hash|
      # Add credits to the count accordingly
      if product_hash["method"] == "credits"

        # Depending on the product size, add the corresponding amount of credits
        if product_hash["size"] == "sample"
          # Get the credit cost for a product sample
          cost = Product.find(product_hash["id"].to_i).sample_price_credits
          count += cost
        elsif product_hash["size"] == "full"
          # Get the credit cost for a full product
          cost = Product.find(product_hash["id"].to_i).full_price_credits
          count += cost
        else
          next
        end

      else
        next
      end
    end
  end

  return count
end

问题

fill\u once

永远运行：它似乎忽略了

，除非self.box\u已填充？

有条件

尝试的解决方案

我尝试从

fill\u once

方法中删除对

fill\u once

的递归调用，并将其拆分为一个

直到
循环（
直到box\u filled？…fill\u once…
），但没有乐趣

更新

def fill_once
  unless self.box_filled?
    # Get a random product from the user's recommendations
    product = self.subscription.user.recommended_product_records[rand(self.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless self.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        product.add_to_box_credits(self.subscription, "sample")
      else
        unless product.full_price_credits.nil?
          product.add_to_box_credits(self.subscription, "full")
        end
      end
      self.save!
    end
    self.fill_once # Here's the recursion
  end
end

多个相同的产品也被添加。我认为问题在于更新的记录没有被操作——只有原始实例。例如，
除非自行添加的产品ID包括在内？product.id
检查原始的box实例，而不是更新的记录，在添加的产品id中看不到任何产品，并将找到的每个产品都放入

解决方案

好了，问题解决了。正如所怀疑的那样，更新的记录没有被传递到迭代器中。我是这样解决的：

# Add one random user recommended product to the box
def fill_once(box=self)
  unless box.box_filled?
    # Get a random product from the user's recommendations
    product = box.subscription.user.recommended_product_records[rand(box.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless box.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "sample")
      else
        unless product.full_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "full")
        end
      end
    end
    fill_once(box)
  end
end

# Add one random user recommended product to the box
def fill_once(box=self)
  unless box.box_filled?
    # Get a random product from the user's recommendations
    product = box.subscription.user.recommended_product_records[rand(box.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless box.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "sample")
      else
        unless product.full_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "full")
        end
      end
    end
    fill_once(box)
  end
end

使用Ruby的默认参数，默认值为
self
，但选择使用更新的记录，允许我根据需要多次通过流传递记录。
，除非self.added\u product\u id.include？product.id
表示不会将重复的产品添加到框中。因此，如果所有推荐的产品都添加到box中，但总积分小于box\u积分，可能会导致无限循环。我不确定，但这可能是原因

你可以加上

puts "Box credits #{self.box_credits} vs. credits: #{self.subscription.credits} "

以前

self.fill_once # Here's the recursion

查看是否发生这种情况。
解决方案

好了，问题解决了。正如所怀疑的那样，更新的记录没有被传递到迭代器中。我是这样解决的：

# Add one random user recommended product to the box
def fill_once(box=self)
  unless box.box_filled?
    # Get a random product from the user's recommendations
    product = box.subscription.user.recommended_product_records[rand(box.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless box.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "sample")
      else
        unless product.full_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "full")
        end
      end
    end
    fill_once(box)
  end
end

# Add one random user recommended product to the box
def fill_once(box=self)
  unless box.box_filled?
    # Get a random product from the user's recommendations
    product = box.subscription.user.recommended_product_records[rand(box.subscription.user.recommended_product_records.length - 1)]
    # Make sure the product hasn't already been included in the box
    unless box.added_product_ids.include? product.id
      # If fresh, add the product to the box, size-dependently
      unless product.sample_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "sample")
      else
        unless product.full_price_credits.nil?
        box = product.add_to_box_credits(box.subscription, "full")
        end
      end
    end
    fill_once(box)
  end
end

使用Ruby的默认参数，默认值为
self
，但是选择使用更新的记录，允许我根据需要多次通过流传递记录。
看起来您可以稍微重构此代码，还有许多注释，如
#将成本添加到计数
，这是不好的做法，但我想说明我的想法！关于递归问题有什么想法吗？你的想法有点不可读，许多不必要的注释，
self
在你可以删除它的地方，结合
除非。。其他的结束
与
相同，除非有什么.nil？
，我不确定，但希望如果你只是重构你的示例，你会在没有帮助的情况下找到解决方案）@IS04我很难理解你的评论，所以也许你也可以重构它？；）有没有更好的方法来编写
，除非是.nil？这是一个好主意，让我尝试一个更大的产品列表。无论哪种方式，代码都不能处理这个问题，这是一个问题。也许它应该计算最大可能的数量，如果无法填充该框，则引发异常。每次尝试一次。也许
fill\u once
应该是一个步骤，循环本身被提取到它自己的方法中（处理这类事情）。嘿，大家，我们在这里检查代码：D有一个，同意！我现在已经处理好了。如果我们可以尝试寻找递归问题的答案，那就很方便了？遗憾的是，这并不能解决问题——产品不断地添加到盒子中，而不考虑约束。多个相同的产品也被添加。我认为问题在于更新的记录没有被操作——只有原始记录。例如，
除非自行添加的产品ID包括在内？product.id
检查原始的box实例，而不是更新的记录。我认为它并没有解决所有问题，我标记您迁移到CodeReview的问题，您可能需要其他审阅建议。