Draper CollectionDecorator and pagination with kaminari

I’m working with kaminari today, and I spent a bit of time getting Draper to co-operate with the pagination. This is a fairly well documented issue, but I figured I’d post about this for my own future reference.

The issue: getting kaminari methods (such as current_page, total_pages, etc) to work on a decorated collection.

The solution: We need to delegate the kaminari methods, so that Draper knows to ignore them.

How to do this?

  1. Create a separate PaginatingDecorator that inherits from CollectionDraper, and delegate the kaminari methods.
class PaginatingDecorator < Draper::CollectionDecorator
delegate :current_page, :total_pages, :limit_value
  1. In your ApplicationDecorator class, make sure that CollectionDecorator knows to look at PaginatingDecorator.
class ApplicationDecorator < Draper::Decorator
def self.collection_decorator_class
  1. If it’s not already the case, make sure your decorator inherits from ApplicationDecorator
class AnimalDecorator < ApplicationDecorator
decorates :animal