"Create" Action for nested resource with multiple Associations in Rails - ruby-on-rails

Question

I have items, that each have multiple (threaded) comments.
The threading is done via a parent key, that points towards another comment.
I just can't get the create action to work properly, I got it far enough to submit into the database, but it didn't have item_id and parent_id set.
I tried form_for [#item, #comment] instead of form_for :comment, url: item_comments_path( #item ) but it didn't help either.
When I look at comment_params in the create action I get this:
Parameters: {"utf8"=>"✓", "comment"=>{"body"=>"examplecommentgoeshere"}, "parent_id"=>"4", "commit"=>"Create Comment", "item_id"=>"4"}
Can anyone help?
Models:
class Item < ActiveRecord::Base
belongs_to :user
has_many :comments, dependent: :destroy
has_many :images, as: :item,
dependent: :destroy
validates :title, presence: true,
allow_blank: false
validates :description, presence: true,
allow_blank: false
validates :user, presence: true,
allow_blank: false
validates :layout, presence: true
end
class Comment < ActiveRecord::Base
belongs_to :user
belongs_to :item
has_many :responses, class_name: "Comment",
foreign_key: "parent_id",
dependent: :destroy
has_one :image, as: :item,
dependent: :destroy
belongs_to :parent, class_name: "Comment"
validates :body, presence: true,
allow_blank: false,
length: { minimum: 10 }
end
Comment Controller:
class CommentsController < ApplicationController
before_filter :findParent
before_filter :find, only: [:update, :destroy, :show]
before_filter :is_logged_in?, only: [:create, :update, :destroy]
before_filter :has_permission?, only: [:update, :destroy]
def new
#comment = Comment.new
end
def create
logger.debug comment_params.inspect
#comment = current_user.comments.build(comment_params)
if #comment.save
redirect_to #item
else
logger.debug #comment.errors.inspect
session[:errorbj] = #comment
redirect_to #item
end
end
[...]
private
def comment_params
params.require(:comment).permit(:body, :parent)
end
private
def find
#comment = Comment.find(params[:id])
end
private
def findParent
#item = Item.find params[:item_id]
end
Item View:
<p>
<h3>Add a comment:</h3>
<%= render partial: 'comments/form', locals: { parent: #item } %>
</p>
Partial comments/form:
<%= form_for :comment, url: item_comments_path( #item ) do |f| %>
<p>
<%= f.label :body %><br>
<%= f.text_area :body %>
</p>
<p>
<%= f.label :image %><br>
<nope>
</p>
<%= hidden_field_tag :parent_id, parent.id %>
<p>
<%= f.submit %>
</p>
<% end %>
From another stackoverflow thread I concluded that the only way to create an object in a multi-association is to do something along the lines of this:
#comment = current_user.comments.build( comment_params.join( { parent_id: <parent.id> } ) )
Other stackoverflow posts however said not to do
#item = Item.new( item_params.join( { user_id: current_user.id } )
So is there really no better way?

Answer 1

i think there are a lot of errors in your code. i hope that i can put that into a form that might help you figure out the fix by yourself:
use form_for [#item, #comment]
findParent should be find_parent
findParent should set a #parent
findParent should find a Comment
the new action should initialize with a parent #comment = Comment.new parent: #parent
hidden_field_tag :parent_id, parent.id should be form.hidden_field :parent
the parent association should be set via comment_params
you don't need the Rails.logger statement, its all in logs/development.log
don't put objects into the session
why is there item and image?
learn more about debugging! http://nofail.de/2013/10/debugging-rails-applications-in-development/

Answer 2

It turns out this is much easier than it seemed.
This is how I ended up doing it:
class CommentsController < ApplicationController
before_filter :findParent, only: [:create]
[...]
def create
#comment = current_user.comments.build(comment_params)
#comment.item = #item
if #comment.save
redirect_to #item
else
session[:errorbj] = #comment
redirect_to #item
end
end