Question

我想使用first_name方法将我的模型实例的last_name和before_save大写。我当然可以这样做：

before_save do 
  self.first_name = first_name.capitalize
  self.last_name = last_name.capitalize
end

但我更倾向于一举改变这两个属性。有没有办法在我的模型中选择某些列并将所需的方法应用于它们？

Answer 1

你可以做这样的事情

before_save :capitalize_attributes

private
   def capitalize_attributes
     capitalizable = ["first_name","last_name"]
     self.attributes.each do |attr,val|
       #based on comment either of these will work
       #if you want to store nil in the DB then
       self.send("#{attr}=",val.strip.capitalize) if capitalizable.include?(attr) && !val.nil?
       #if you want to store a blank string in the DB then 
        self.send("#{attr}=",val.to_s.strip.capitalize) if capitalizable.include?(attr)
     end
   end

然后，您只需将要大写的属性添加到capitalizable数组即可。我在某些模型中对upcase所有字符串使用类似的代码，只是为了保持数据的一致性。

Answer 2

这只是@ engieeringmnky答案的另一个版本：

before_save :capitalize_attributes

private
   def capitalize_attributes
     self.attributes.select{ |a| ["first_name","last_name"].include? a }.each do |attr, val|
       self.send("#{attr}=", val.try(:strip).try(:capitalize))
     end
   end

Answer 3

在@ engineersmnky的基础上，通过Concerns（更多here）进一步回答Rails 4+：

应用程序/模型/关切/ model_hooks.rb

module ModelHooks
  extend ActiveSupport::Concern

  included do
    before_save :capitalize_attributes
  end

  def capitalize_attributes
     self.attributes.each do |attr,val|
       # if the attribute only has spaces, then this will store nil in the DB
       self.send("#{attr}=",val.strip.capitalize) if self.capitalizable_attrs.include?(attr) && !val.nil?
     end    
  end
end

然后在你的模特中：

class Trail < ApplicationRecord
  include ModelHooks

  def capitalizable_attrs
    ["name"] # return an array of attributes you want to capitalize
  end

end

在Rails before_save方法中大写多个属性

3 个答案: