Question

I am trying to allow comments on a nested resource and I am getting an undefined method ‘comment’ for # in app/controllers/comments_controller.rb:7:in `create’ when i select the create comment button. As I’m still new to ruby and rails, I followed the code in the getting started guide and I can’t seem to figure out why the error.

Associations are:

has_many :comments
belongs_to :restaurant

In my routes

resources :restaurants do
    resources :comments
 end 

In the comments controller

def create
    @restaurant = Restaurant.find(params[:restaurant_id])
    @comment = @restaurant.comments.create(params[:comment])
    redirect_to restaurant_path
end

In my restaurant show template

<%= form_for([@restaurant, @restaurant.comments.build]) do |f| %>
<h2>Add a comment</h2>
  <div>
    <%= f.text_area :body %>
  </div>
  <div>
    <%= f.submit %>
<% end %>

Answer 1

You should do the following on the first line in your create statement

raise params.to_yaml

You should see something like the following

utf8: ✓
authenticity_token: ...
comment: !ruby/hash:ActiveSupport::HashWithIndifferentAccess
  commenter: Test Commenter
  body: Test Comment
commit: Create Comment
action: create
controller: comments
restaurant_id: '1'    

The rest of your site should look something like the following

comments_controller.rb

def create
  @restaurant = Restaurant.find(params[:restaurant_id])
  @comment = @restaurant.comments.create(params[:comment])
  redirect_to restaurant_path(@restaurant)
end

comments.rb

class Comment < ActiveRecord::Base
 has_many :comments
 belongs_to :restaurant
end

restaurants.rb

class Restaurant < ActiveRecord::Base
 attr_accessible :content, :name, :title
 has_many :comments
end

You probably missed a step in guide. Everything else looks to be alright.