Display a form with selected values from URL

Rails
1

Hi there,

I have an author model and a book model.

I’m trying to create a “add new book” link for each author from the
authors index page, that would point to a new book page, with the the
author select field already “selected” to the good option.
the author select in the new book form is created with
collection_select().

I don’t know how to pass such a variable in a url using rails url
schema. I’ve looked in the link_to documentation, but nothing about
this specific case.

any help would be greatly appreciated,
thanks in advance.

2

Two ways the good and the bad :

Good:

url:
/author/1/book/new

BookController
new
@author = Author.find(params[:author_id])
@book = @author.books.new

or (not so good)

BookController

@author = Author.find(params[:author])
@book = Book.new
@book.author = @author

Should work too…

3

thanks for your help

/authors/3/books/new gives me a

Routing Error
No route matches “/authors/3/books/new” with {:method=>:get}

I guess i need to update my routes.rb for this to work ?

i’ve tried this :

map.resources :books, :path_prefix => “/authors/:author_id”

without success …

if that helps : i’m using rails 2 with REST.

4

I’ve managed to do it the old way using /books/new?author_id=
and
@author = Author.find(params[:author_id])
@book = @author.books.new
as you’ve suggested.

thanks again.