app/models/comment.rb
class Comment < ActiveRecord::Base
acts_as_nested_set :scope => [:commentable_id, :commentable_type]
attr_accessible :commentable, :body, :user_id
validates :body, :presence => true
validates :user, :presence => true
# NOTE: install the acts_as_votable plugin if you
# want user to vote on the quality of comments.
#acts_as_votable
belongs_to :commentable, :polymorphic => true
# NOTE: Comments belong to a user
belongs_to :user
# Helper class method that allows you to build a comment
# by passing a commentable object, a user_id, and comment text
# example in readme
def self.build_from(obj, user_id, comment)
new \
:commentable => obj,
:body => comment,
:user_id => user_id
end
#helper method to check if a comment has children
def has_children?
self.children.any?
end
# Helper class method to lookup all comments assigned
# to all commentable types for a given user.
scope :find_comments_by_user, lambda { |user|
where(:user_id => user.id).order('created_at DESC')
}
# Helper class method to look up all comments for
# commentable class name and commentable id.
scope :find_comments_for_commentable, lambda { |commentable_str, commentable_id|
where(:commentable_type => commentable_str.to_s, :commentable_id => commentable_id).order('created_at DESC')
}
# Helper class method to look up a commentable object
# given the commentable class name and id
def self.find_commentable(commentable_str, commentable_id)
commentable_str.constantize.find(commentable_id)
end
end