Rails second level nested resource - ruby-on-rails

Question

I am having a problem with showing any of the views for my resource Field. I have this kind of association: User has one farm, farm has many fields.
My models:
User.rb
has_one :farm
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable,
:token_authenticatable, :confirmable, :lockable, :timeoutable
attr_accessible :email, :password, :password_confirmation, :remember_me, :username
--
Farm.rb
belongs_to :user
has_many :fields
attr_accessible :name, :contact, :adress, :user_id
--
Field.rb
belongs_to :farm
attr_accessible :crop, :longitude, :latitude, :occupied, :farm_id
My rake routes:
user_farm_fields GET /users/:user_id/farm/:farm_id/fields(.:format)
{:action=>"index", :controller=>"fields"}
POST /users/:user_id/farm/:farm_id/fields(.:format)
{:action=>"create", :controller=>"fields"}
new_user_farm_field GET /users/:user_id/farm/:farm_id/fields/new(.:format) {:action=>"new", :controller=>"fields"}
edit_user_farm_field GET /users/:user_id/farm/:farm_id/fields/:id/edit(.:format){:action=>"edit", :controller=>"fields"}
user_farm_field GET /users/:user_id/farm/:farm_id/fields/:id(.:format) {:action=>"show", :controller=>"fields"}
PUT /users/:user_id/farm/:farm_id/fields/:id(.:format) {:action=>"update", :controller=>"fields"}
DELETE /users/:user_id/farm/:farm_id/fields/:id(.:format) {:action=>"destroy", :controller=>"fields"}
user_farms GET /users/:user_id/farm(.:format)
{:action=>"index", :controller=>"farms"}
POST /users/:user_id/farm(.:format)
{:action=>"create", :controller=>"farms"}
new_user_farm GET /users/:user_id/farm/new(.:format)
{:action=>"new", :controller=>"farms"}
edit_user_farm GET /users/:user_id/farm/:id/edit(.:format)
{:action=>"edit", :controller=>"farms"}
user_farm GET /users/:user_id/farm/:id(.:format)
{:action=>"show", :controller=>"farms"}
PUT /users/:user_id/farm/:id(.:format)
{:action=>"update", :controller=>"farms"}
DELETE /users/:user_id/farm/:id(.:format)
{:action=>"destroy", :controller=>"farms"}
users GET /users(.:format)
{:action=>"index", :controller=>"users"}
POST /users(.:format)
{:action=>"create", :controller=>"users"}
new_user GET /users/new(.:format)
{:action=>"new", :controller=>"users"}
edit_user GET /users/:id/edit(.:format)
{:action=>"edit", :controller=>"users"}
user GET /users/:id(.:format)
{:action=>"show", :controller=>"users"}
PUT /users/:id(.:format)
{:action=>"update", :controller=>"users"}
DELETE /users/:id(.:format)
{:action=>"destroy", :controller=>"users"}
new_user_session GET /accounts/sign_in(.:format)
{:action=>"new", :controller=>"devise/sessions"}
user_session POST /accounts/sign_in(.:format)
{:action=>"create", :controller=>"devise/sessions"}
destroy_user_session GET /accounts/sign_out(.:format)
{:action=>"destroy", :controller=>"devise/sessions"}
user_password POST /accounts/password(.:format)
{:action=>"create", :controller=>"devise/passwords"}
new_user_password GET /accounts/password/new(.:format)
{:action=>"new", :controller=>"devise/passwords"}
edit_user_password GET /accounts/password/edit(.:format)
{:action=>"edit", :controller=>"devise/passwords"}
PUT /accounts/password(.:format)
{:action=>"update", :controller=>"devise/passwords"}
cancel_user_registration GET /accounts/cancel(.:format)
{:action=>"cancel", :controller=>"devise/registrations"}
user_registration POST /accounts(.:format)
{:action=>"create", :controller=>"devise/registrations"}
new_user_registration GET /accounts/sign_up(.:format)
{:action=>"new", :controller=>"devise/registrations"}
edit_user_registration GET /accounts/edit(.:format)
{:action=>"edit", :controller=>"devise/registrations"}
PUT /accounts(.:format)
{:action=>"update", :controller=>"devise/registrations"}
DELETE /accounts(.:format)
{:action=>"destroy", :controller=>"devise/registrations"}
user_confirmation POST /accounts/confirmation(.:format)
{:action=>"create", :controller=>"devise/confirmations"}
new_user_confirmation GET /accounts/confirmation/new(.:format)
{:action=>"new", :controller=>"devise/confirmations"}
GET /accounts/confirmation(.:format)
{:action=>"show", :controller=>"devise/confirmations"}
user_unlock POST /accounts/unlock(.:format)
{:action=>"create", :controller=>"devise/unlocks"}
new_user_unlock GET /accounts/unlock/new(.:format)
{:action=>"new", :controller=>"devise/unlocks"}
GET /accounts/unlock(.:format)
{:action=>"show", :controller=>"devise/unlocks"}
home_index GET /home/index(.:format)
{:controller=>"home", :action=>"index"}
root /
{:controller=>"home", :action=>"index"}
My form for making new field:
<%= form_for([#user, #farm, #field]) do |f| %>
<% if #field.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#field.errors.count, "error") %> prohibited this field from being saved:</h2>
<ul>
<% #field.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :crop %><br />
<%= f.text_field :crop %>
</div>
<div class="field">
<%= f.label :longitude %><br />
<%= f.text_field :longitude %>
</div>
<div class="field">
<%= f.label :latitude %><br />
<%= f.text_field :latitude %>
</div>
<div class="field">
<%= f.label :occupied %><br />
<%= f.check_box :occupied %>
</div>
<div class="field">
<%= f.label :description %><br />
<%= f.text_area :description %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
And my corresponding new method for field:
def new
#farm = Farm.where("user_id = ?", current_user).first
#user = current_user
#field = Field.new
respond_to do |format|
format.html # new.html.erb
format.json { render json: #field }
end
My routes.rb:
resources :users do
resources :farms, :path => 'farm' do
resources :fields
end
end
devise_for :users, :path => 'accounts'
After I try going to this link for creating new field :
<%= link_to 'New Field', new_user_farm_field_path(#user, #farm, #field) %>
I get this message:
undefined method `user_fields_path' for #<#<Class:0x496e1b0>:0x496b6d8>

Answer 1

On the surface level, the problem is likely to do with the form_for helper trying to set the url for your form without the correct nesting structure
You may wish to try this:
#app/views/fields/new.html.erb
<%= form_for [#user, #farm, #field], url: user_farm_fields_path do |f| %> #-> the create path
--
Nesting
There may be some deeper issues for you:
The corresponding route helper would be publisher_magazine_photo_url,
requiring you to specify objects at all three levels. Indeed, this
situation is confusing enough that a popular article by Jamis Buck
proposes a rule of thumb for good Rails design:
Resources should never be nested more than 1 level deep.
The caveat here, is that the docs stipulate you can do what you're doing (deep nesting) (I originally thought you shouldn't). Anyway, I think you might want to consider making your routes more "shallow", as to ensure they are more manageable.
To do this, I'd like you to consider the role of user in what you're doing:
User has_one Farm
This means that when you call resources :farms, you've got an antipattern - how can you select a farm if a user only has one? Surely a better way would be to remove any dependence on the user, create a singular resource for :farm, and then set the fields flow as you had them before
Here's how I'd do it:
#config/routes.rb
root "farms#index"
resources :farms, only: :index
resource :farm do #-> domain.com/farm (authentictable)
resources :fields #-> domain.com/farm/fields/new
end
#app/controllers/farms_controller.rb
Class FarmsController < ApplicationController
before_action :authenticate_user!, except: :index
def show
#farm = current_user.farm
end
def index
#farms = Farm.all
end
end
#app/models/user.rb
Class User < ActiveRecord::Base
has_one :farm
before_create :build_farm #-> creates farm if not already built
end
This will give you the ability to work everything back from being connected to the current_user:
#app/views/fields/new.html.erb
<%= form_for [#farm, #field] do |f| %>
<%= f.text_area :field_name %>
<%= f.submit %>
<% end %>
#app/controllers/fields_controller.rb
Class FieldsController < ApplicationController
before_action :authenticate_user!
def new
#farm = current_user.farm
#field = #farm.fields.new
end
def create
#farm = current_user.farm
#field = #farm.fields.new field_params
end
private
def field_params
params.require(:field).permit(:field_name)
end
end