Creating a nested object with child in a form - ruby-on-rails

Question

I'm a rails noob that's tryin to do something in his app.
My problem is:
I have a Corso model, a Libro model and an Annuncio model. Corso has_many Libro, Libro has_many Annuncio, Annuncio belongs_to Libro and Libro belongs_to Corso. I want a form where the user can create a Libro (that MUST be associated to a Corso) and meanwhile an Annuncio of that Libro must be created. I'm literally freaking out, I saw hundreds of discussions but nothing solved my problem. Every time I change something I get some different errors.
My focus is:
- how to pass the corso_id (I mean, the objects Corso are already defined in the db) to the new Libro when I submit the form;
-I don't see why a Libro object is created (all fields nil) but an Annuncio object doesn't. It seems like the code #libro.annuncios.build in LibroController/new is useless.
I hope you will help me to get this form working.
LibroController:
class LibroController < ApplicationController
def new
#corso = Corso.find(params[:corso_id])
#libro = #corso.libros.build
#libro.annuncios.build
end
def create
#corso = Corso.find(params[:corso_id])
#libro = #corso.libros.build(libro_params)
if #libro.save
redirect_to #libro
else
redirect_to root_path
end
end
def show
#libro = Libro.find(params[:id])
end
def index
end
private
def libro_params
params.require(:libro).permit(:titolo, :autori, :casa_editrice, :edizione, :anno_pubblicazione, :ISBN, :immagine, :corso_id, annuncios_attributes[:prezzo, :note])
end
end
AnnuncioController:
class AnnuncioController < ApplicationController
def new
#annuncio = Annuncio.new
end
def create
#libro = Libro.find(params[:libro_id])
#annuncio = #libro.annuncio.build(annuncio_params)
if #annuncio.save
redirect_to #libro
else
redirect_to root_path
end
end
private
def annuncio_params
params.require(:annuncio).permit(:prezzo, :note)
end
end
Libro Model:
class Libro < ApplicationRecord
belongs_to :corso, inverse_of: :libros
has_many :annuncios, inverse_of: :libro
accepts_nested_attributes_for :annuncios
end
Annuncio Model:
class Annuncio < ApplicationRecord
belongs_to :utente, inverse_of: :annuncios
belongs_to :libro, optional: true, inverse_of: :annuncios
end
Corso Model:
class Corso < ApplicationRecord
belongs_to :facolta
has_many :libros
validates :nome, uniqueness: true
end
routes.rb (a little messed up)
Rails.application.routes.draw do
get 'facolta/new'
get 'sessions/create'
get 'sessions/destroy'
get 'users/new'
get 'corso/index'
get 'auth/:provider/callback', to: 'sessions#create'
get 'auth/failure', to: redirect('/')
get 'signout', to: 'sessions#destroy', as: 'signout'
resources :sessions, only: [:create, :destroy]
resource :home, only: [:show]
root 'facolta#index'
get 'corso_new' => 'corso#new'
get 'libro_new' => 'libro#new'
get 'about_us' => 'static_pages#about_us'
get 'faq' => 'static_pages#faq'
resources :facolta do
resources :corso
end
resources :corsos, shallow: true do
resources :libro
end
resources :libros do
resources :annuncio
end
resources :user do
resources :annuncio
end
end
views/libro/new
<h1>FORM DI REGISTRAZIONE HERE</h1>
<div class="row">
<div class="col-md-6 col-md-offset-3">
<%= form_for([#corso, #libro]) do |libro| %>
<p>
<%= libro.label :titolo %>
<%= libro.text_field :titolo %>
</p>
<p>
<%= libro.label :autori %>
<%= libro.text_field :autori %>
</p>
<p>
<%= libro.label :casa_editrice %>
<%= libro.text_field :casa_editrice %>
</p>
<p>
<%= libro.label :edizione %>
<%= libro.text_field :edizione %>
</p>
<p>
<%= libro.label :anno_pubblicazione %>
<%= libro.text_field :anno_pubblicazione %>
</p>
<p>
<%= libro.label :ISBN %>
<%= libro.text_field :ISBN %>
</p>
<p>
<%= libro.label :immagine %>
<%= libro.text_field :immagine %>
</p>
<%= libro.fields_for :annuncios do |annuncio| %>
<p>
<%= annuncio.label :prezzo %>
<%= annuncio.text_field :prezzo %>
</p>
<p>
<%= annuncio.label :note %>
<%= annuncio.text_field :note %>
</p>
<% end %>
<%= libro.hidden_field :corso_id, value: params[:post_id]%>
<%= libro.submit "Inserisci il libro", class: "btn btn-primary" %>
<% end %>
</div>
</div>
schema.rb
create_table "annuncios", force: :cascade do |t|
t.integer "user_id"
t.integer "libro_id"
t.string "prezzo"
t.text "note"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["libro_id"], name: "index_annuncios_on_libro_id"
t.index ["user_id"], name: "index_annuncios_on_user_id"
end
create_table "corsos", force: :cascade do |t|
t.string "nome"
t.integer "facolta_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["facolta_id"], name: "index_corsos_on_facolta_id"
end
create_table "facolta", force: :cascade do |t|
t.string "nome"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "libros", force: :cascade do |t|
t.string "titolo"
t.string "autori"
t.string "casa_editrice"
t.string "edizione"
t.string "anno_pubblicazione"
t.string "ISBN"
t.string "immagine"
t.integer "corso_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["corso_id"], name: "index_libros_on_corso_id"
end
create_table "users", force: :cascade do |t|
t.string "provider"
t.string "uid"
t.string "name"
t.string "oauth_token"
t.datetime "oauth_expires_at"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "email"
end
EDIT: edited with #arieljuod advices

Answer 1

You don't need to merge the corso_id here: #libro = #corso.libros.build(libro_params.merge({corso_id: #corso.id})). ActiveRecord already sets the corso_id since you are doing #corso.libros.build(...).
You also don't need that hidden_field with the Corso id since you already have that from the URL.
You may want to do #libro = #corso.libros.build on your new action too.
And finally, I think this is the main problem: this is wrong belongs_to :corso, inverse_of: :corsos, it should be inverse_of: :libros
Fix the other things I point out too to clean up your code.
EDIT:
to add a select do something like this:
= libro.select :corso_id, options_from_collection_for_select(Corso.all, :id, :name)