设置虚拟属性Rails活动模型

Question

How do I set a virtual attribute that sets the first and last name, when I call Quote.new()?

The before_save :assign_name method does not seem work. I get an error

NoMethodError: undefined method `before_save' for Quote:Class

CONTROLLER:

  quote = {name: "John Doe", City: "New York"}
  Quote.new(quote) 

MODEL:

class Quote
    include ActiveModel::Model

    before_save :assign_name

    attr_accessor :name, :first, :last, :city


    def assign_name
      title_split = self.name.split(" / ")
      self.first = title_split[0]
      self.last = title_split[1]
    end
end

Answer 1

You can use something like this

class Quote
  include ActiveModel::Model
  attr_accessor :name, :first, :last, :city

  def initialize(attributes={})
    super
    assign_name(name)
  end

  def assign_name(name)
    title_split = name.split(" / ")
    self.first = title_split[0]
    self.last = title_split[1]
  end
end

Also link to documentation here

Answer 2

before_save is defined in ActiveRecord. You need to let your class inherit from ActiveRecord::Base as the following:

class Quote < ActiveRecord::Base
end

And if you put the method in "before_save" callback, that means the method will be called only when Quote#save is executed. For example,

quote = {name: "John Doe", City: "New York"}
q = Quote.new(quote)
q.save