JSOM::Pagination

An easy to use JSON:API support for web applications.

Installation

Add this line to your application's Gemfile:

gem 'jsom-pagination'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install jsom-pagination

Usage

For arrays

paginator = JSOM::Pagination::Paginator.new
collection = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
paginated = paginator.call(collection, params: { number: 2, size: 3 }, base_url: 'https://example.com')

For ActiveRecord collections

paginator = JSOM::Pagination::Paginator.new
collection = Article.published
paginated = paginator.call(collection, params: { number: 2, size: 3 }, base_url: 'https://example.com')

Meta data object

You can call meta on the paginated collection to easily get meta information about the paginated results

paginated.meta
# => #<JSOM::Pagination::MetaData total=10 pages=4>

paginated.meta.to_h
# => {:total=>10, :pages=>4}

Links object

You can call links on the paginated collection to easily get collection of pagination links for the client

paginated.links
# => #<JSOM::Pagination::Links:0x00007fdf5d0dd2b8 @url="https://example.com", @page=#<JSOM::Pagination::Page number=2 size=3>, @total_pages=4, @first="https://example.com?page[size]=3", @prev="https://example.com?page[size]=3", @self="https://example.com?page[number]=2&page[size]=3", @next="https://example.com?page[number]=3&page[size]=3", @last="https://example.com?page[number]=4&page[size]=3">

paginated.links.to_h
# => {
#   :first=>"https://example.com?page[size]=3",
#   :prev=>"https://example.com?page[size]=3",
#   :self=>"https://example.com?page[number]=2&page[size]=3",
#   :next=>"https://example.com?page[number]=3&page[size]=3",
#   :last=>"https://example.com?page[number]=4&page[size]=3"
# }

Rendering using fast_jsonapi

options = { meta: paginated.meta.to_h, links: paginated.links.to_h }
render json: serializer.new(paginated.items, options)

Summary

Using the information above, you can put everything all together by using jsom-pagination in a ruby framework of your choice.

Below is an illustration in Rails:

# app/controllers/concerns/paginable.rb
module Paginable
    extend ActiveSupport::Concern
    
    def paginator
      JSOM::Pagination::Paginator.new
    end
    
    def pagination_params
      params.permit![:page] # defaults to 20 pages 
    end
    
    def paginate(collection)
      paginator.call(collection, params: pagination_params, base_url: request.url)
    end
  
    def render_collection(paginated)
      options = {
        # meta: paginated.meta.to_h, # Will get total pages, total count, etc.
        links: paginated.links.to_h
      }
      paginated_result = serializer.new(paginated.items, options)
  
      render json: paginated_result
    end
end

# app/controllers/articles_controllers.rb
class ArtclesController < ApplicationController
    include Paginable

    def index
        articles = articles = Article.order('created_at DESC')
        paginated = paginate(articles)
    
        articles.present? ? render_collection(paginated) : :not_found
    end

    private

    def serializer
        ArticleSerializer
    end
end

The response from the paginated json will look like below:

{
  "data": [
    {
      "id": "5404329",
      "type": "article",
      "attributes": {
        "author": "Canan Ercan",
        "copies": 10000,
        "publisher": "Webster & Canan Publishers",
        "price": "700"
      }
    }
  ],
  "links": {
    "first": "http://127.0.0.1:3000/api/v1/articles",
    "prev": "http://127.0.0.1:3000/api/v1/articles?page[number]=349",
    "self": "http://127.0.0.1:3000/api/v1/articles?page[number]=350",
    "next": "http://127.0.0.1:3000/api/v1/articles?page[number]=351",
    "last": "http://127.0.0.1:3000/api/v1/articles?page[number]=352"
  }
}

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/useo-pl/jsom-pagination. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the JSOM::Pagination project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.