How to include a controller with a Ruby on Rails gem?

Question

I'm trying to contribute to an open source project and I need a controller to handle a couple of forms that need to be submitted in.

I created these controllers inside a directory inside the gem called app/controllers/gemname/my_controller.rb.

However, when I try to access the controller, it seems not to be loaded (I get a name error just as if I typed something like NonExistentController).

How do I load my controller with the gem?

Thanks!

Is your `MyController` defined inside `Gemname` module? If it's not rails will expect it to be placed in `app/controllers/my_controller.rb`. — KL-7, Dec 31 '11 at 16:29
Please read this guide http://guides.rubyonrails.org/plugins.html — taro, Dec 31 '11 at 16:48
KL-7, how do I define MyController inside of the Gemname module? taro, thanks for the info. I did, that doesn't contain the information I'm looking for though. — Yuval Karmi, Dec 31 '11 at 18:13

score 10 · Accepted Answer · edited Sep 20 '15 at 12:19

10

Let's assume your gem is called MyGem and you have a controller called SuperController that you want to use in the app. Your controller should be defined as:

module MyGem
  class SuperController < ApplicationController
    def whatever
      ...
    end
  end
end

and in your gem directory it should live at app/controllers/my_gem/super_controller.rb (not under the lib folder). Check out the source for Devise as they do the same thing.

[Edit] You may learn something from A Guide To Starting Your Own Rails Engine Gem regarding your current project.

edited Sep 20 '15 at 12:19

casraf

21,085
9
56
91

answered Dec 31 '11 at 19:23

Michelle Tilley

157,729
40
374
311

Thanks a lot! I love the `guide link` you mentioned. – Siwei Jan 31 '13 at 06:04
I was struggling with this all yesterday. I think today will be a lot easier. Thanks! – Rimian Apr 25 '13 at 23:22
@Brandon How much have things changed in Rails Engines between Rails 3 and 4? – JagWire Oct 29 '14 at 17:39

Rimian · Answer 2 · 2013-04-25T23:44:56.893

The guide in Brandon's answer is very helpful but only applies to rails 3.0. Since 3.1 you can create a plugin. Like this: rails plugin new my_engine --mountable

See this helpful guide:
http://namick.tumblr.com/post/17663752365/how-to-create-a-gemified-plugin-with-rails-3-2-rspec
(> Rails 3.0)

Rails official guide (edge):
http://edgeguides.rubyonrails.org/engines.html
http://edgeguides.rubyonrails.org/plugins.html

Old enginex:
https://github.com/josevalim/enginex
(3.0 only)

How to include a controller with a Ruby on Rails gem?

2 Answers2

Linked