Question

Suppose I have a User, Post and a Comment model, that allow a user to comment on a post. I’ve set up a polymorphic relationship like follows:

class User < ActiveRecord::Base
  has_many :comments
end

class GroupRun < ActiveRecord::Base
  has_many :comments, :as => :commentable
end

class Comment < ActiveRecord::Base
  belongs_to :commentable, polymorphic: true
  belongs_to :user
end

I’d now like to allow a user to comment on another user, but am running into difficulty. I’d have thought I could do something along the lines of has_many :notes, :as_commentable but this doesn’t work.

Any advice?

Answer 1

You have to add this to your User model:

class User < ActiveRecord::Base
  has_many :comments
  has_many :comments_from_other_users, :as => :commentable, :class_name => 'Comment'
end

I know the name of the relation is awful but it is easily understandable and you can change it as you want.

So you should have this after:

current_user.comments.each do |comment|
  comment.user # author of the comment
  comment.commentable # object that you posted the comment on (GroupRun for instance)
end
current_user.comments_from_other_users.each do |comment|
  comment.user # author of the comment
  comment.commentable # user on which the comment is posted (should be equal here to current_user)
end