ruby-on-rails-4 - Rails 与表单 collection_select 的多态关联，无需嵌套

Question

我的应用程序中有以下模型

class User < ActiveRecord::Base
has_many :articles
has_many :tour_companies
has_many :accomodations
end

class Articles < ActiveRecord::Base
belongs_to :user
belongs_to :bloggable, :polymorphic => true
end

class TourCompany < ActiveRecord::Base
belongs_to :user
has_many :articles, :as => :bloggable
end

class Accommodation < ActiveRecord::Base
belongs_to :user
has_many :articles, :as => :bloggable
end

现在我的问题是我希望登录用户能够写一篇文章并使用表单 collection_select 来选择文章应该与他/她的哪个旅游公司或住宿相关联，我如何在 rails 4 中做到这一点？我如何从表单集合选择中选择可博客类型和 ID？我不想要嵌套资源

Answer 1

从 Rails 4.2 开始，这可以通过 rails/globalid 处理.这个较新的选项被 Rails 的 ActiveJob 使用。它使解析和查找设置起来非常简单。
首先，检查您的 Gemfile.lock为 globalid .对于 Rails 5，它包括在内。
神奇的一切都发生在模型中......
文章型号:

# Use :to_global_id to populate the form
def bloggable_gid
  bloggable&.to_global_id
end

# Set the :bloggable from a Global ID (handles the form submission)
def bloggable_gid=(gid)
  self.bloggable = GlobalID::Locator.locate gid
end

要了解它的作用，请打开 rails console .玩转 gid = TourCompany.first.to_global_id和 GlobalID::Locator.locate gid .
现在你的其余代码是股票 Rails 的东西......
文章 Controller :

# consider building the collection in the controller.
# For Rails 5, this would be a `before_action`.
def set_bloggables
  @bloggables = TourCompany.all + Accomodation.all
end

# permit :bloggable_gid if you're using strong parameters...
def article_params
  params.require(:article).permit(:bloggable_gid)
end

文章形式:

<%= f.collection_select(:bloggable_gid, @bloggables, :to_global_id, :to_s) %>

如需更多演练， Simple Polymorphic Selects with Global IDs博文很有帮助。