ruby-on-rails - 在 Rails 中干燥我的 has_many

Question

我有一个模型类，其中包括:

class Group < ActiveRecord::Base
  has_many :subscriptions
  has_many :users, :through => :subscriptions

  has_many :admins, :through => :subscriptions, :source => :user, :conditions => "subscriptions.role = #{ROLES[:admin]}"
  has_many :subscribers, :through => :subscriptions, :source => :user, :conditions => "subscriptions.role >= #{ROLES[:subscriber]}"
  has_many :authors, :through => :subscriptions, :source => :user, :conditions => "subscriptions.role >= #{ROLES[:author]}"
  has_many :pending_subscribers, :through => :subscriptions, :source => :user, :conditions => "subscriptions.pending = true"
end

:through => :subscriptions, :source => :user 的重复次数让我很困扰。我知道在路由文件中，您可以执行 map.with_options。我的模型协会有类似的东西吗？

Answer 1

with_options 实际上是对 Object 的扩展, 所以你也可以在你的 ActiveRecord::Base 中使用它

with_options :through => :subscriptions, :source => :user do |obj|
  obj.has_many :admins, :conditions => "subscriptions.role = #{ROLES[:admin]}"
  obj.has_many :subscribers, :conditions => "subscriptions.role >= #{ROLES[:subscriber]}"
  obj.has_many :authors, :conditions => "subscriptions.role >= #{ROLES[:author]}"
  obj.has_many :pending_subscribers, :conditions => "subscriptions.pending = true"
end