class User < ActiveRecord::Base
  include Restrictable # Would be nice to not need this line
  restrictable except: [:id,:name,:email]
end

user = User.find(1)
user.restricted_data # Returns all columns except :id,:email

如果我正确地理解了你的问题,那就是关于如何编写这样一个问题,而不是关于restricted_data的实际返回值.我会实现这样的关注骨架：

require "active_support/concern"

module Restrictable
  extend ActiveSupport::Concern

  module ClassMethods
    attr_reader :restricted

    private

    def restrictable(except: []) # Alternatively `options = {}`
      @restricted = except       # Alternatively `options[:except] || []`
    end
  end

  def restricted_data
    "This is forbidden: #{self.class.restricted}"
  end
end

然后你可以：

class C
  include Restrictable
  restrictable except: [:this,:that,:the_other]
end

c = C.new
c.restricted_data  #=> "This is forbidden: [:this,:the_other]"

这符合您设计的界面,但是except键有点奇怪,因为它实际上限制了这些值而不是允许它们.