ruby-on-rails - 在 `includes` 急切加载上重用范围作为过滤器

Question

将其分解为一个最小的示例:

class User < ActiveRecord::Base
  has_many :profiles
  has_many :addresses, through: :profiles
end

class Profile < ActiveRecord::Base
  belongs_to :user
  has_many :addresses
end

class Address < ActiveRecord::Base
  belongs_to :profile

  def self.active_by_date
    where(is_active: true).order('updated_at DESC')
  end
end

class UsersController < ApplicationController
  def index
    @users = User.includes(profiles: :addresses)
  end
end

假设在上面的 Controller 操作中，我想为每个用户的配置文件预先加载按日期排序的事件地址。我可以这样做:

class User < ActiveRecord::Base
  has_many :profiles
  has_many :addresses, through: :profiles
  has_many :active_addresses_by_date, through: :profiles,
    source: :addresses, class_name: Address,
    conditions: ['address.is_active = ?', true],
    order: 'address.updated_at DESC'
end

class UsersController < ApplicationController
  def index
    @users = User.includes(profiles: :active_addresses_by_date)
  end
end

但是由于我不能重用 active_by_date范围在 Address ，条件和顺序现在存在于两个地方。我想把它干掉，就像在第一个版本中一样，“按日期的事件地址”的概念只存在于 Address 中。模型。理想情况下，我可以调用 @users.each { |user| user.addresses.active_by_date }。不发出任何查询。这在 ActiveRecord 下是否可行，如果可以，我将如何处理？

Answer 1

也许我不明白，但如果你改变 active_by_date 就会发生这种情况。到

  def self.active_by_date
    where("addresses.is_active = ?", true).order('addresses.updated_at DESC')
  end

是不是可以调用 User.includes(profiles: :addresses).active_by_date ?