如何有效地管理与关联模型的多态关联？

Question

I am trying to do the following: events can either have individual students compete, or teams of students. So I set it up polymorphically, as follows:

class Event < ActiveRecord::Base
  belongs_to :event_type
  has_many :competitors
  has_many :students, through: :competitors, :source => :participant, :source_type => 'Student'
end

class Competitor < ActiveRecord::Base
  belongs_to :event
  belongs_to :participant, polymorphic: true

  # also has other attributes, like points, and grade
end

class Student < ActiveRecord::Base
  has_many :competitors, :as => :participant
  has_many :events, :through => :competitors
end

class Team < ActiveRecord::Base
  has_many :competitors, :as => :participant
  has_many :events, :through => :competitors
  has_many :team_members
  has_many :students, :through => :team_members
end

tl;dr: How do I work with these using Resourceful controllers?

I already have an events controller which allows me to CRUD it's properties. I have a Students controller that does the same. So now I need the Competitors controller to combine them. And it's there that I draw a blank.

What I'd like is to be able to choose an events competitors on one screen - from a list of student checkboxes. If I create a nested route like

resources :events, shallow: true do
  resources :competitors, shallow: true
end

I can then go to events/1/competitors to show the list of competitors. But then should it show Teams, or Students? I don't want it to become a mess of if/elses. So should I have separate controllers for those two? How would they be named? And how would I interact with them?

Let's say I do make a controller specifically for student competitors:

resources :events, shallow: true do
  resources :student_competitors, shallow: true
end

I'd get events/1/student_competitors . This would show a list of all students competing in that event. Let's say I wanted to make that list a set of checkboxes with an Update button. How would I construct that form?

<%= simple_form_for(@event, :html => { :class => 'form-vertical' }) do |f| %>
  <% @students.each do |student| %>
    <%= check_box_tag "event[student_ids][]", student.id, student.events.include?(@event) %>
    <span><%= student.name %></span>
  <% end %>

  <%= f.button :submit, 'Update Competitors' %>
<% end %>

This would submit the form back to events/1 , whereas I'd like it to be submitted to the StudentCompetitors controller, but I can't call simple_form_for with a collection like simple_form_for(@event, @competitors) and have it construct a path to the update action.

Essentially, I'm not sure how best to go about all this. Am I trying to be too strict, sticking to a resources? Your help is appreciated.

Answer 1

I used a singular resource:

resources :events, shallow: true do
  resource :student_competitors, shallow: true
end

Thus I can edit student competitors at events/1/student_competitors , and I use simple_form_for as:

<%= simple_form_for(:student_competitors, url: event_student_competitors_path, :method => :put, :html => { :class => 'form-vertical' }) do |f| %>