Wor::Paginate is a gem for Rails that simplifies pagination, particularly for controller methods, while standardizing JSON output for APIs. It's meant to work both as a standalone pagination gem and as an extra layer over Kaminari and will_paginate.

Add the following line to your application's Gemfile:

gem 'wor-paginate'

And then execute:

$ bundle

Or install it yourself as:

$ gem install wor-paginate

Then you can run rails generate wor:paginate:install to create the initializer for configuration details, including default formatter class, page and limit params and default page number.

The basic use case is to paginate using default values. This is achieved by including the module in a controller and calling render_paginate in the method that needs pagination.

  class DummyModelsController < ApplicationController
    include Wor::Paginate

    def index
        render_paginated DummyModel
    end
  end

The first parameter to render_paginated can be multiple things:

• ActiveRecord/ActiveRecord::Relation
• Enumerables (for example, arrays and ranges)
• Pre-paginated Kaminari or will_paginate relations (original pagination will be ignored)

The response to the index will then be:

{
  "page": [
    {
      "id": 1,
      "name": "1c",
      "something": 27
    },
    {
      "id": 2,
      "name": "i",
      "something": 68
    },
    ...
    {
      "id": 25,
      "name": "2m",
      "something": 32
    }
  ],
  "count": 25,
  "total_pages": 2,
  "total_count": 28,
  "current_page": 1,
  "next_page": 2
}

Page number is passed through the page option of the render_paginated method. If none is supplied, params[:page] will be used, (or the default parameter configured in the initializer). By default, if the page parameter is not present we will use 1 as the page (or the default page parameter configured in the initializer). The amount of items is passed through the limit option of the render_paginated method. If none is supplied, params[:limit] will be used (or the default parameter configured in the initializer). Default is 25. The default serializer and formatter will be used.

A custom serializer for each object can be passed using the each_serializer option:

render_paginated DummyModel, each_serializer: CustomDummyModelSerializer

where the serializer is just an ActiveModel::Serializer.

A formatter is an object that defines the output of the render_paginated method. In case the application needs a different format for a request, it can be passed to the render_paginated method using the formatter option:

render_paginated DummyModel, formatter: CustomFormatter

or it can also be set as a default in the initializer.

A new formatter can be created inheriting from the default one. The format method should be redefined returning something that can be converted to json.

class CustomFormatter < Wor::Paginate::Formatter
  def format
    { page: serialized_content, current: current_page }
  end
end

Available helper methods are:

• current_page: integer with the current page
• count: number of items in the page (post-pagination)
• total_count: number of total items (pre-pagination)
• total_pages: number of pages given the current limit (post-pagination)
• paginated_content: its class depends on the original content passed to render_paginated, it's the paginated but not yet serialized content.
• serialized_content: array with all the items after going through the serializer (either the default or a supplied one)

If either Kaminari or will_paginate are required in the project, Wor::Paginate will use them for pagination with no code or configuration change.

You can use the be_paginated matcher to test your endpoints. It also accepts the with chain method to receive a formatter.

You only need to add this in your rails_helper.rb

# spec/rails_helper.rb
require 'wor/paginate/rspec'

And in your spec do

# spec/controllers/your_controller.rb
describe YourController do
  describe '#index' do
    it 'checks that the response keys matches with the default formatter' do
      get :index
      expect(response_body(response)).to be_paginated
    end
  end

  describe '#index_with_custom_formatter' do
    it 'checks that the response keys matches with the custom formatter' do
      get :index_custom_formatter
      expect(response_body(response)).to be_paginated.with(CustomFormatter)
    end
  end
end

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Run rubocop lint (bundle exec rubocop -R --format simple)
5. Run rspec tests (bundle exec rspec)
6. Push your branch (git push origin my-new-feature)
7. Create a new Pull Request

This project is maintained by Hugo Farji, Ignacio Coluccio, and Alan Halatian. It was written by Wolox.

wor-paginate is available under the MIT license.

Copyright (c) 2017 Wolox

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