Rails 4. Set up comment editing functionality with nested resources - ruby-on-rails

Question

I have the following models: User, Product and Comment. The user can add, edit and delete comments to the product. I've successfully set up adding and deleting functionality and now I'm struggling with editing, for some reason, it caused me a number of difficulties.
My current code returns this error when I click on the edit comment link:
NoMethodError at /products/800/comments/8/edit
undefined method `comments' for nil:NilClass
Here's how my comment model looks like:
# id :integer not null, primary key
# body :text
# created_at :datetime not null
# updated_at :datetime not null
# user_id :integer
# product_id :integer
class Comment < ActiveRecord::Base
belongs_to :user
belongs_to :product
# validations ...
end
In User model I have has_many :comments and in Product - has_many :comments, dependent: :destroy.
In my routes.rb file I have the following nested resources:
resources :products, only: [:show] do
resources :comments, only: [:create, :edit, :update, :destroy]
end
My ProductsController has the only method show and nothing else, and here's how it looks like:
def show
product = Product.find(params[:id])
photos = ProductsPhoto.where(product: product)
case product.products_category.name
when 'Violin'
#product = [product, Violin.where(product: product).first, photos]
when 'Guitar'
#product = [product, Guitar.where(product: product).first, photos]
when 'Saxophone'
#product = [product, Saxophone.where(product: product).first, photos]
when 'Piano'
#product = [product, Piano.where(product: product).first, photos]
end
#comment = Comment.new
#comments = Comment.where(product_id: product.id).order('created_at DESC')
end
And now here's my CommentsController, which has create, edit, update and destroy:
class CommentsController < ApplicationController
def create
#product = Product.find(params[:product_id])
#comment = #product.comments.create(comment_params)
#comment.user_id = current_user.id
if #comment.save
redirect_to #product, notice: 'Comment Created!'
else
redirect_to #product, notice: 'Something went wrong...'
end
end
def show
end
def edit
#product = Product.find(params[:product_id])
#comment = #product.comments.find(params[:id])
end
def update
#product = Product.find(params[:product_id])
#comment = #product.comments.find(params[:id])
respond_to do |format|
if #comment.update_attributes(comment_params)
format.html do
redirect_to [#comment.product, #comment], notice: 'Comment Updated!'
end
else
format.html { render action: 'edit', notice: 'Something went wrong...' }
end
end
end
def destroy
#product = Product.find(params[:product_id])
#comment = #product.comments.find(params[:id])
#comment.destroy!
redirect_to #product, notice: 'Comment Deleted!'
end
private
def comment_params
params.require(:comment).permit(:body)
end
end
My _form view is located at views/products/_form.html.erb and looks like this:
<%= simple_form_for([#product[0], #product[0].comments.build]) do |f| %>
<%= f.error_notification %>
<%= f.input :body, required: true, placeholder: 'Type in your comment...', input_html: { class: 'form-control'}, label: false %>
<%= f.button :submit, class: 'btn btn-primary btn-block' %>
<% end %>
And in the views/products/show.html.erb I render the partial of comments and there are the links for destroying and editing the comment, they look like this:
<%= link_to edit_product_comment_path(comment.product, comment) do %>
<span class="glyphicon glyphicon-pencil"></span>
<% end %>
<%= link_to [comment.product, comment], method: :delete do %>
<span class="glyphicon glyphicon-remove"></span>
<% end %>
the delete link works fine and the edit link doesn't.
Maybe I've mistaken with routes, here're the routes for comments:
product_comments POST /products/:product_id/comments(.:format) comments#create
edit_product_comment GET /products/:product_id/comments/:id/edit(.:format) comments#edit
product_comment PATCH /products/:product_id/comments/:id(.:format) comments#update
PUT /products/:product_id/comments/:id(.:format) comments#update
DELETE /products/:product_id/comments/:id(.:format) comments#destroy
In my views/comments/edit.html.erb I render the same form:
<%= render 'products/form' %>
however, when I click on the edit link, I get the following error:
NoMethodError at /products/800/comments/8/edit
undefined method `comments' for nil:NilClass
at the very first line of the _form.html.erb.
I hope I've provided enough information to describe the problem.
So, could you please help me with resolving that issue with comments editing?

Answer 1

It's too early this morning...
This is not correct :
<%= simple_form_for([#product, #product.comments.build]) do |f| %>
Try :
<%= simple_form_for [#comment.product_id, #comment], url: product_comment_path(#comment.product_id, #comment) do |f| %>
Added section
(All of this is assuming that we are working with a single #comment, not the #comments collection. Based on your comments about the delete working.)
To reply to your comment, yes, absolutely you do need separate forms for "new" versus "edit" action for your child table, comments.
Form "new" naming convention is comments/_form.html.erb, the "edit" form would be comments/_form_edit.html.erb,
I would open the "new" action form for comments...
<%= simple_form_for([:product, #comment]) do |f| %>
And the "edit" action...
<%= simple_form_for [#comment.product_id, #comment], url: product_comment_path(#comment.product_id, #comment) do |f| %>
Sorry I forgot the URL on the previous version, I have updated the code snippet above to reflect this change as well. Caveat: There may be other ways to construct this link, but this is how I have implemented the case of having a product (parent) with reviews/comments (many children).
Nested attributes
In further response to your comment, I believe some of what you're looking for could be achieved by using nested attributes in forms. This is another topic. I would get the new/edit form simple cases working and then add complexity.