Question

I’m trying to create a Rails 3 Engine using MongoMapper. I’m having a world of pain getting it going. Here is my model:

module GoodComments
  class Comment
    include MongoMapper::Document

    key :comment,   String

  end
end

Super simple, I know! My config/routes.rb:

GoodComments::Engine.routes.draw do
  resources :comments
end

I created a config/application.rb:

require File.expand_path('../boot', __FILE__)

module GoodComments
  class Application < Rails::Application
    config.generators do |g|
      g.orm :mongo_mapper    # :active_record
      g.template_engine :erb # :haml
      g.test_framework :rspec, :fixture => true, :views => false
      g.fixture_replacement :factory_girl, :dir => "spec/factories"
    end
  end
end

I ran rails generate scaffold_controller Comment -o mongo_mapper and my controllers were generated. When I run my server and go to http://localhost:3000/good_comments/comments, I get an error:

LoadError in GoodComments::CommentsController#index

Expected /Users/shamoon/Sites/good_comments/app/models/comment.rb to define Comment
Rails.root: /Users/shamoon/Sites/good_comments/test/dummy

Any help?

Answer 1

It looks like your controller was expecting a class called Comment in comment.rb, so maybe the controller needs to be operating in the same module? Or you would just have to specify some non-default configurations or be more specific about which model the controller should use.

Also in my MongoMapper app I have a few more lines than you added to the top of config/application.rb:

require File.expand_path('../boot', __FILE__)

# from http://mongomapper.com/documentation/getting-started/rails.html
# replace:
# require 'rails/all'
# with:
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "rails/test_unit/railtie"
# Uncomment for asset pipelining in Rails 3.1
# require "sprockets/railtie"