Rails 4 deep nesting with routing

Question

Here is my route.rb:

  resources :books, :path => "librairie" do
      resources :chapters, shallow: true
  end


  resources :chapters do 
     resources :titles, shallow: true
  end
  resources :titles

Here's my models:

class Book < ActiveRecord::Base
has_many :chapters
end

class Chapter < ActiveRecord::Base
belongs_to :book
has_many :titles
end

class Title < ActiveRecord::Base
belongs_to :chapter
end

What I would like to do is choose a book in the library and see a page with all the chapters and titles (belonging to each chapter). This works. (library = AllBooks || Book#Show = Book with all chapters and titles)

Then, click on the title and get a page to see the text corresponding. This also works. (Title#Show)

Now I would like to add a button back at the top of the view of Title#Show with the following:

title of the book : chapter : title and with a link which go to the book (Book#Show)

However, after spending time in the controller I begin to be completely lost and my result looks worse and worse. How do I add such a button?

Answer 1

Ok, so you can do this

class Title < ActiveRecord::Base
  belongs_to :chapter
  has_one :book, through: :chapter
end

Then in your controller you can do

class TitlesController
  def show
    @title = Title.find(params[:id])    
    @book = @title.book
  end  
end

Which means in your view you can do

<%= link_to book_path(@book) do %>
  <%= "#{ @book.title } #{ @chapter.title } #{ @title.title }" %>
<% end %>

I assume you're finding chapter in a before_action here.