Rails 4 Nested Resources/Routes... almost there...? - ruby-on-rails

Question

I have three models - users, manufacturers, and lines. I need users to have multiple manufacturers, and each manufacturer to have multiple lines. I'm to the point where lines is finally pulling the manufacturer_id on the _form, but now it's not saving the 'name' of the 'line', only the id. It'll save the 'name' as nil, like it's not passing in the name from the form. I've read the standard docs on this and I can't for the life of me get it working. It keeps hanging up on the final create stage in the controller, and I have a feeling that I've got a lot of things wrong in the paths of the form and the controller. Hoping someone will take it easy on me and help me get the whole shebang working.
user.rb
class User < ActiveRecord::Base
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
has_many :manufacturers
end
manufacturer.rb
class Manufacturer < ActiveRecord::Base
belongs_to :user
has_many :lines
end
line.rb
class Line < ActiveRecord::Base
belongs_to :manufacturer
end
lines_controller.rb
class LinesController < ApplicationController
before_action :set_line, only: [:show, :edit, :update, :destroy]
before_filter :load_manufacturer
# GET /lines
# GET /lines.json
def index
#lines = Line.all
end
# GET /lines/1
# GET /lines/1.json
def show
end
# GET /lines/new
def new
#manufacturer = Manufacturer.find(params[:manufacturer_id])
#line = #manufacturer.lines.build
end
# GET /lines/1/edit
def edit
end
# POST /lines
# POST /lines.json
def create
#line = #manufacturer.lines.build
respond_to do |format|
if #line.save
format.html { redirect_to #line, notice: 'Line was successfully created.' }
format.json { render action: 'show', status: :created, location: #line }
else
format.html { render action: 'new' }
format.json { render json: #line.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /lines/1
# PATCH/PUT /lines/1.json
def update
respond_to do |format|
if #line.update(line_params)
format.html { redirect_to #line, notice: 'Line was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: #line.errors, status: :unprocessable_entity }
end
end
end
# DELETE /lines/1
# DELETE /lines/1.json
def destroy
#line.destroy
respond_to do |format|
format.html { redirect_to lines_url }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_line
#line = Line.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def line_params
params.require(:line).permit(:name, :manufacturer_id)
end
def load_manufacturer
#manufacturer = Manufacturer.find(params[:manufacturer_id])
end
end
lines/_form.html.erb
<%= form_for [#manufacturer,#line] do |f| %>
<% if #line.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#line.errors.count, "error") %> prohibited this line from being saved:</h2>
<ul>
<% #line.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %><br>
<%= f.text_field :name %>
</div>
<div class="field">
<%= f.label :manufacturer_id %><br>
<%= f.text_field :manufacturer_id %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
routes.rb
Linecarder::Application.routes.draw do
resources :manufacturers do
resources :lines
end
devise_for :users
root "pages#home"
get "about" => "pages#about"
match 'users/:id' => 'users#show', :via => "get"
match '/users', :to => 'users#index', :as => "all_users", :via => "get"
match '/users/:name' => 'users#show', via: :get, as: :public_profile
end
rake routes
Prefix Verb URI Pattern Controller#Action
manufacturer_lines GET /manufacturers/:manufacturer_id/lines(.:format) lines#index
POST /manufacturers/:manufacturer_id/lines(.:format) lines#create
new_manufacturer_line GET /manufacturers/:manufacturer_id/lines/new(.:format) lines#new
edit_manufacturer_line GET /manufacturers/:manufacturer_id/lines/:id/edit(.:format) lines#edit
manufacturer_line GET /manufacturers/:manufacturer_id/lines/:id(.:format) lines#show
PATCH /manufacturers/:manufacturer_id/lines/:id(.:format) lines#update
PUT /manufacturers/:manufacturer_id/lines/:id(.:format) lines#update
DELETE /manufacturers/:manufacturer_id/lines/:id(.:format) lines#destroy
manufacturers GET /manufacturers(.:format) manufacturers#index
POST /manufacturers(.:format) manufacturers#create
new_manufacturer GET /manufacturers/new(.:format) manufacturers#new
edit_manufacturer GET /manufacturers/:id/edit(.:format) manufacturers#edit
manufacturer GET /manufacturers/:id(.:format) manufacturers#show
PATCH /manufacturers/:id(.:format) manufacturers#update
PUT /manufacturers/:id(.:format) manufacturers#update
DELETE /manufacturers/:id(.:format) manufacturers#destroy
new_user_session GET /users/sign_in(.:format) devise/sessions#new
user_session POST /users/sign_in(.:format) devise/sessions#create
destroy_user_session DELETE /users/sign_out(.:format) devise/sessions#destroy
user_password POST /users/password(.:format) devise/passwords#create
new_user_password GET /users/password/new(.:format) devise/passwords#new
edit_user_password GET /users/password/edit(.:format) devise/passwords#edit
PATCH /users/password(.:format) devise/passwords#update
PUT /users/password(.:format) devise/passwords#update
cancel_user_registration GET /users/cancel(.:format) devise/registrations#cancel
user_registration POST /users(.:format) devise/registrations#create
new_user_registration GET /users/sign_up(.:format) devise/registrations#new
edit_user_registration GET /users/edit(.:format) devise/registrations#edit
PATCH /users(.:format) devise/registrations#update
PUT /users(.:format) devise/registrations#update
DELETE /users(.:format) devise/registrations#destroy
root GET / pages#home
about GET /about(.:format) pages#about
GET /users/:id(.:format) users#show
all_users GET /users(.:format) users#index
public_profile GET /users/:name(.:format) users#show

Answer 1

Update the create action as below:
def create
#line = #manufacturer.lines.build(line_params) ## Pass the params via line_params
respond_to do |format|
if #line.save
format.html { redirect_to #line, notice: 'Line was successfully created.' }
format.json { render action: 'show', status: :created, location: #line }
else
format.html { render action: 'new' }
format.json { render json: #line.errors, status: :unprocessable_entity }
end
end
end
You are not passing the params that you received from the form. Hence, name of line is not getting saved in database.
Also, in order to permit the attributes for mass-assignment(strong parameters) pass them via line_params method.
UPDATE for OP's question in the comment to resolve
undefined method 'line_url'... for 'format.html { redirect_to #line, notice: 'Line was successfully created.' }'
Use this
format.html { redirect_to manufacturer_line_path(#manufacturer, #line), notice: 'Line was successfully created.' }
instead of
format.html { redirect_to #line, notice: 'Line was successfully created.' }