Rails, getting a part of a URL /modelstuff/31 --- how to get 31?

Question

I'm interested in learning in Rails 3, how to grab the URL with something like params[:urlpath]

and then indexing it with /

so if I had a url like examples:

/books/1
/books/1/authors/3
/books/1/authors/3/chapters
/books/1/authors/3/chapters/33

I could always obtain 1

something like params[:urlpath] index[2]

I need this to populate the following which is happening on the page:

$.ajax({
    url: '/nav/sidenav',
    data: "urlpath=" + urlpath
});

ideas? thxs

Answer 1

Add the following to your routes.rb:

match '/modelstuff/:id' => "controller#method"

Then you can use params[:id]

Answer 2

If your URLs look like /books/1/authors/3/chapters/33

Then your routes should be:

resources :books do 
  resources :authors do
    resources :chapters
  end
end

This is called Nested Routes.

Then, in your controller:

/app/controllers/chapters_controller.rb

def show
  @book = Book.find(params[:book_id])
  @author = @book.authors.find(params[:author_id])
  @chapter = @author.chapters.find(params[:id])
end

Sort of magic.