Rails callback/listener approach to shared service object behavior from controllers

gistfile1.rb

class CommentsController < ApplicationController

  def create
    CommentCreator.new(current_user, params[:comment], self).create
  end
  
  
  private
  
  def create_successful(comment)
    redirect_to comment_path(comment)
  end
  
  def create_failure(comment, errors)
    @comment = comment
    render :edit
  end
end


class Api::CommentsController < ApplicationController

  def create
    CommentCreator.new(current_user, params[:comment], self).create
  end
  
  
  private
  
  def create_successful(comment)
    render json: comment
  end
  
  def create_failure(comment, errors)
    render json: {errors: errors}
  end
end

class CommentCreator
  
  def initialize(user, comment_params, listener)
    @comment = user.comments.new(comment_params)
    @listener = listener
  end
  
  def create
    if @comment.save
      @listener.create_successful(@comment)
    else
      @listener.create_failure(@comment, @comment.errors.full_messages)
    end
  end
end