Topic: Subclassing ApplicationController in a gem
(also posted in http://stackoverflow.com/questions/1134 r-in-a-gem )
I thought I'd come up with a slick way to extend ApplicationController in a Rails 3.x gem.
In my gem's lib/my_namespace/my_controller.rb, I had:
class MyNamespace::MyController < ApplicationController
# getting classname of the subclass to use for lookup of the associated model, etc.
# and storing the model_class in an instance variable
# define :some_method, :another_method, etc.
attr_accessor :subclass_defined_during_initialize # etc.
but when the Gem is loaded, app/controllers/application_controller.rb is not yet loaded, so it fails:
in `require': cannot load such file -- my_gem_name/application_controller (LoadError)
As a workaround, I had defined ApplicationController in my gem's lib/gem_namespace/application_controller.rb as:
class ApplicationController < ActionController::Base
I assumed that even though I had defined it there, it would be redefined in my Rails 3 application's app/controllers/application_controller.rb, such that both controllers in the application that extended ApplicationController and controllers that extended MyNamespace::MyController would directly or indirectly extend the ApplicationController defined in app/controllers/application_controller.rb.
However, we noticed that after loading the gem, controllers that extend ApplicationController were unable to access methods defined in app/controllers/application_controller.rb. Also, the ApplicationHelper (app/helpers/application_helper.rb) module was no longer being loaded by other helper modules.
How can I extend ApplicationController within the controller in my gem for the purpose allowing others to subclass my controller that subclasses ApplicationController, so that I can use before_filter, after_filter, and use initialize to access the subclass's name to determine the associated model's class that it is then storing in a private accessor on the subclass?
Last edited by gsw (2012-07-05 13:54:55)