允许在数字字段中使用逗号 [英] Allowing commas in a numerical field

问题描述

这是一个如此愚蠢的问题，我觉得我一定错过了一些简单的东西.我有一个带有 quantity 字段的表单.人们在输入数量时不断输入逗号(例如，他们输入 12,000 表示一万二千)，所以我想在保存数量之前去掉逗号(12000在示例中)转换为数据库中的整数列.

This is such a dumb question that I feel like I must be missing something simple. I have a form with a quantity field. People keep typing commas when they enter the quantity (for example, they type 12,000 to indicate twelve thousand) so I would like to strip out the commas before saving the quantity (12000 in the example) into an integer column in the database.

到目前为止我已经尝试了两种方法.按照在这个SO问题

So far I have tried two methods. Overriding the setter method as suggested in this SO question

  def quantity=(num)
    num.gsub!(',', '') if num.is_a?(String)
    self[:quantity] = num.to_i
  end

这在某种意义上是有效的.如果我在数量字段中输入 12,000 并提交表单，我会在数据库中得到 12000.问题是它还绕过了所有 quantity 验证.例如，我不再可以验证数量值的存在.这不好.

This works in a sense. If I type 12,000 in the quantity field and submit the form, I get 12000 in the database. The problem is that it also bypasses all quantity validations. No longer can I validate the presence of a value for quantity for example. This is not good.

我也尝试过使用 before 验证回调(而不是覆盖 setter):

I have also tried to use a before validation callback (instead of overriding the setter):

  before_validation :sanitize_quantity

  def sanitize_quantity
    # Doesn't wok because quantity.to_i already called by this point.
  end

这不起作用，因为当数量达到回调方法时，Rails 已经在其上调用了 to_i.这意味着 12,000 将在到达回调时被截断为 12.再一次，不好.

This doesn't work because by the time the quantity has reached the callback method, Rails has already called to_i on it. This means that 12,000 will be truncated to 12 by the time it reaches the callback. Once again, not good.

除了在客户端去除逗号之外，我还能尝试什么?

What else can I try aside from stripping the commas on the client-side?

最后一点，我知道这实际上是一件愚蠢的事情，因为某些国家/地区以不同的方式使用句点和逗号.无论如何，我仍然需要这样做.

As a final note, I am aware that this is essentially a dumb thing to do because certain countries use periods and commas in different ways. I still need to do it anyway.

推荐答案

我实际上在阅读我的问题时发现了这一点.

I actually figured this out just as I was reading over my question.

关键是使用虚拟属性.

class Job < ActiveRecord::Base
  def flexible_quantity
    quantity
  end

  def flexible_quantity=(quantity)
    self.quantity = quantity.gsub(',', '') unless quantity.blank?
  end
 end

然后在表单中，使用虚拟属性.

Then in the form, use the virtual attribute.

<%= f.text_field :flexible_quantity %>

现在验证 flexible_quantity 值是否存在.

Now validate the presence of the flexible_quantity value instead.

class Job < ActiveRecord::Base
  validates :flexible_quantity, presence: true

  # The cool this is that we can leave the numericality validation on the quantity field.
  validates :quantity, presence: true, numericality: { only_integer: true }
end

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