Ruby on Rails - Adding comments to post - ruby-on-rails

Question

Trying to learn RoR. Currently adding comments to posts by user. So far I have a posts model, comments model and post_comments model (to associate the two). So for in 'rails console' I can run: (say I set p = Post.first and c = Comment.first)
p.comments << c
This forms an association so it works in the console. I just can't seem to get the comments to form this association from the UI. So far I am creating the comments at "comments/new" (not sure if this is the issue. Do they need to be created on the "show view" for "post").
Here are some code snippets
Controllers
comments_controller.rb
class CommentsController < ApplicationController
def index
#comment = Comment.all
end
def new
#comment = Comment.new
end
def create
#comment = Comment.new(commentParams)
if #comment.save
flash[:success] = "Comment successfully added"
redirect_to comments_path(#comment)
else
render 'new'
end
end
def show
#comment = Comment.find(params[:id])
end
private
def commentParams
params.require(:comment).permit(:comment)
end
end
posts_controller
class PostsController < ApplicationController
before_action :setPost, only: [:edit, :update, :show, :destroy, :sold]
before_action :requireUser, except: [:index, :show]
before_action :requireSameUser, only: [:edit, :update, :destroy, :sold]
def index
#posts = Post.paginate(page: params[:page], per_page: 20)
end
def new
#post = Post.new
end
def create
#post = Post.new(postParams)
#post.user = currentUser
if #post.save
flash[:success] = "Post successfully added."
redirect_to post_path(#post)
else
render 'new'
end
end
def update
if #post.update(postParams)
flash[:success] = "Post successfully updated."
redirect_to post_path(#post)
else
render 'edit'
end
end
def show
end
def edit
end
def sold
#post.toggle(:sold)
#post.save
redirect_to post_path(#post)
end
def destroy
#post.destroy
flash[:danger] = "Item successfully deleted."
redirect_to posts_path
end
private
def postParams
params.require(:post).permit(:title, :price, :description, category_ids:[])
end
def setPost
#post = Post.find(params[:id])
end
def requireSameUser
if currentUser != #post.user and !currentUser.admin
flash[:danger] = "You can only edit or delete your own items"
redirect_to root_path
end
end
end
Models
comment.rb
class Comment < ActiveRecord::Base
belongs_to :post_comments
belongs_to :user
belongs_to :post
end
post_comment.rb
class PostComment < ActiveRecord::Base
belongs_to :post
belongs_to :comment
end
post.rb
class Post < ActiveRecord::Base
belongs_to :user
has_many :post_categories
has_many :categories, through: :post_categories
has_many :post_comments
has_many :comments, through: :post_comments
validates :title, presence: true,
length: { minimum: 4, maximum: 20 }
validates :description, presence: true,
length: { maximum: 1000 }
validates :user_id, presence: true
end
Views
posts/show.html.erb
<p>Comments: <%= render #post.comments %></p>
This renders the partial below
comments/_comment.html.erb
<%= link_to comment.name, comment_path(comment) %>
Finally is the new comment page as it is.
comments/new.html.erb
<h1>New Comment</h1>
<%= render 'shared/errors', obj: #comment %>
<div class="row">
<div class="col-xs-12">
<%= form_for(#comment, :html => {class: "form-horizontal", role: "form"}) do |f| %>
<div class="form-group">
<div class="control-label col-sm-2">
<%= f.label :comment %>
</div>
<div class="col-sm-8">
<%= f.text_area :comment, rows: 3, class: "form-control", placeholder: "Please enter a comment", autofocus: true %>
</div>
</div>
<div class="form-group">
<div class="center col-sm-offset-1 col-sm-10">
<%= f.submit class: "btn btn-primary btn-lg" %>
</div>
</div>
<% end %>
Any help would be greatly received.
Update
Log
Started GET "/posts/2" for ::1 at 2016-01-15 12:39:55 +0000
Processing by PostsController#show as HTML
Parameters: {"id"=>"2"}
[1m[36mPost Load (0.1ms)[0m [1mSELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT 1[0m [["id", 2]]
[1m[35mUser Load (0.1ms)[0m SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1 [["id", 1]]
[1m[36m (0.1ms)[0m [1mSELECT COUNT(*) FROM "posts" WHERE "posts"."user_id" = ?[0m [["user_id", 1]]
[1m[35mCategory Exists (0.1ms)[0m SELECT 1 AS one FROM "categories" INNER JOIN "post_categories" ON "categories"."id" = "post_categories"."category_id" WHERE "post_categories"."post_id" = ? LIMIT 1 [["post_id", 2]]
[1m[36mCategory Load (0.0ms)[0m [1mSELECT "categories".* FROM "categories" INNER JOIN "post_categories" ON "categories"."id" = "post_categories"."category_id" WHERE "post_categories"."post_id" = ?[0m [["post_id", 2]]
Rendered categories/_category.html.erb (0.2ms)
[1m[35mComment Load (0.1ms)[0m SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = ? [["post_id", 2]]
Rendered comments/_comment.html.erb (0.1ms)
Rendered posts/show.html.erb within layouts/application (6.5ms)
[1m[36mCategory Load (0.1ms)[0m [1mSELECT "categories".* FROM "categories"[0m
Rendered layouts/_navigation.html.erb (0.9ms)
Rendered layouts/_messages.html.erb (0.1ms)
Rendered layouts/_footer.html.erb (0.1ms)
Completed 200 OK in 52ms (Views: 50.3ms | ActiveRecord: 0.5ms)

Answer 1

As a comment can belong to a single post only, you do not need an association table (post_comments). You just need a simple one-to-many relationship.
Your post comment would be:
class Post < ActiveRecord::Base
has_many :comments
...
end
And comment would be like this:
class Comment < ActiveRecord::Base
belongs_to :post
...
end
Just make sure that you have the necessary post_id column in the comments table (you can check the db/schema.rb file). If that is missing, you can use the following migration to add it:
class AddPostIdToComments < ActiveRecord::Migration
def change
add_column :comments, :post_id, :integer
add_index :comments, :post_id
end
end
You also need to make sure you keep somewhere the reference to the post, whenever a user tries to create a comment to a post. You can add this in a hidden field to your comments/new.html.erb template. You could set the hidden field in the new action, in PostsController, after passing it through the URL.
So, in your posts/show.html.erb template you would have:
<%= link_to "Add Comment", new_comment_path(post_id: #post.id) %>
In your new action, in PostsController:
def new
#comment = Comment.new(post_id: params[:post_id])
end
And finally the hidden field in your form would be:
<%= f.hidden_field :post_id %>
Finally, add the post_id parameter to the list of permitted parameters in CommentsController.

Answer 2

instead of
In your new action, in PostsController:
def new
#comment = Comment.new(post_id: params[:post_id])
end
you can use this in the form views
<%= form.hidden_field :post_id, value: "#{params[:post_id]}" %>