Question

In my widgets_controller.rb I’ve got the following method

# GET /widgets/index_of_deleted
def index_of_deleted
  @widgets = Widget.order("name").deleted

  respond_to do |format|
    format.html
  end
end

And I’ve got many other models that will use this method. How can I create a module that has this method in a generic form, so that I can DRY up my controllers? I think the solution would be to call this..

index_of_deleted("widget")

..in my widgets_controller.rb. Or perhaps I can use the controller’s name and just include this module in each controller that would use this method?

Specifically, what would the implementation of index_of_deleted look like within my Module?

Answer 1

You can write modules and include them. Start by making a file in lib, maybe like so:

module WidgetExtras
  def index_of_deleted(widget)
    # implementation
  end
end

Then, in your WidgetsController, near the top, simple add:

include WidgetExtras

You might want to more explicitly namespace your modules (just nest them).

Edit

I’m not sure it’s worth abstracting that really, how many models are there that need this functionality? You could write a helper instead to find deleted items:

module ApplicationHelper
  def deleted_for_class( klass )
    klass.order('name').deleted
  end
end

But then why not just make a scope for ‘deleted Model by name’…

Edit 2

You could write the implementation to set an instance variable…

def index_of_deleted( widget_name )
  klass = Kernel.const_get(widget_name.classify)
  instance_variable_set( "@#{widget_name.pluralize}", klass.order('name').deleted )
end