Nested Resources For Pundit Policy - ruby-on-rails

Question

I'm still trying to wrap my head around Pundit policies. I think I'm close but I've wasted too much time trying to figure this out. My Posts policy works great, but trying to authorize comments, I am getting undefined errors...
comments_controller.rb
class CommentsController < ApplicationController
before_action :find_comment, only: [:show, :edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]
def create
#post = Post.find(params[:post_id])
#comment = #post.comments.create(params[:comment].permit(:comment))
#comment.user_id = current_user.id if current_user
authorize #comment
#comment.save
if #comment.save
redirect_to post_path(#post)
else
render 'new'
end
end
def edit
authorize #comment
end
def update
authorize #comment
if #comment.update(params[:comment].permit(:comment))
redirect_to post_path(#post)
else
render 'edit'
end
end
def destroy
authorize #comment
#comment.destroy
redirect_to post_path(#post)
end
private
def find_comment
#post = Post.find(params[:post_id])
#comment = #post.comments.find(params[:id])
end
end
comment_policy.rb
class CommentPolicy < ApplicationPolicy
def owned
comment.user_id == user.id
end
def create?
comment.user_id = user.id
new?
end
def new?
true
end
def update?
edit?
end
def edit?
owned
end
def destroy?
owned
end
end
The formatting and indenting is a bit off... thats not how I code I swear
class ApplicationPolicy
attr_reader :user, :post
def initialize(user, post)
raise Pundit::NotAuthorizedError, "must be logged in" unless user
#user = user
#post = post
end
def index?
false
end
def show?
scope.where(:id => post.id).exists?
end
def create?
false
end
def new?
create?
end
def update?
false
end
def edit?
update?
end
def destroy?
false
end
def scope
Pundit.policy_scope!(user, post.class)
end
class Scope
attr_reader :user, :scope
def initialize(user, scope)
#user = user
#scope = scope
end
def resolve
scope
end
end
end

Answer 1

You initialized your resource in ApplicationPolicy as #post. And since your CommentPolicy inherits from ApplicationPolicy and uses its initialization, it only has access to #post. Best option is to keep it as record:
class ApplicationPolicy
attr_reader :user, :record
def initialize(user, record)
raise Pundit::NotAuthorizedError, "must be logged in" unless user
#user = user
#record = record
end
## code omitted
end
class CommentPolicy < ApplicationPolicy
def owned
record.user_id == user.id
end
## code omitted
end
Basically you can call it anything you want but record makes more sense as it will be used in different policy subclasses.