Problem using a form with nested routes in rails 3

I have a database structure where my Articles have many People (through a join, but that is working fine)

What I would like to happen is that when people create an article they can at the same time create new people

Ie the path should be of the form article/new/people/new

In fact, without using nested routes I managed this by using this approach

article.rb (model)

attr_accessor :new_person

articles_controller.rb

  def create
    @article = Article.new(params[:article])

    if params[:add_person]
      @person = Person.check_if_exists_or_create(@article.new_person["first_name"], @article.new_person["last_name"])
      if @person.save
        @article.people << @person
        @article.new_person = nil
      end
      render :action => "new" and return
    end
...

  end

form.erb

<%= form_for @article  do |f| %>
...

      <%= fields_for :new_person do |p| %>

        <% if @person && @person.errors.any? %>
          <%= render :partial => "shared/error_messages", :object => @person %>
        <% end %>

        <div class="field">
          <%= p.label :first_name, "First Name" %>
          <%= p.text_field :first_name %>
        </div>

        <div class="field">
          <%= p.label :last_name, "Last Name" %>
          <%= p.text_field :last_name %>
        </div>

        <%= submit_tag "Add Person", :name => "add_person" %>

      <% end %>
...
  <p>
    <%= f.submit %>
  </p>


<% end %>

This works OK to an extent but now the form is becoming more complicated with other fields I thought I could refactor it to take advantage of nested routes.

Additionally, it is adding a lot of logic to the create controller - and further down to line I might consider making these actions javascript in which case I understand determining the specific button pressed by a controller is more complicated.

For these reasons I thought that a nested route approach might be a more natural fit.

For existing articles it works fine eg /articles/1/people/new with no problems.

I know that nesting forms is a no-no for html validation reasons among other things so I have tried开发者_Python百科 numerous combinations of form_for and fields_for to achieve the goal of:

on the articles/new page

submitting the main form to articles/new submitting the "sub" form with the new_person fields to articles/new/people/new

and making the change to doing this by UJS as painless as possible

The warmest I think I have got was with this error

No route matches {:controller=>"people", :article_id=>#<Article id: nil, title: nil, published_on: nil, created_at: nil, updated_at: nil, people_count: nil, organizations_count: nil>}

I am guessing that the issue is there is no article_id to relate the person to at that point.

But in fact I am only really interested in adding that person to the database and then creating a relationshop to the article which is then stored when the entire article is saved.

Apologies for the long post but wanted to be comprehensive in my question.

Any advice, including alternative approaches that would fit my objectives better would be much appreciated. I have watched the railcasts relating to nested forms and nested routes and read all I can find online but haven't found a solution to the /model/new/submodel/new form issue.

Many thanks.