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:page_facing_up: Link header pagination for Rails and Grape APIs.
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Latest commit e9a6649 Mar 2, 2016 @davidcelis Merge pull request #59 from Domon/fix-version-number-for-grape-in-readme
Fix version number of api-pagination for grape in README


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Paginate in your headers, not in your response body. This follows the proposed RFC-5988 standard for Web linking.


In your Gemfile:

# Requires Rails (Rails-API is also supported), or Grape
# v0.10.0 or later. If you're on an earlier version of
# Grape, use api-pagination v3.0.2.
gem 'rails', '>= 3.0.0'
gem 'rails-api'
gem 'grape', '>= 0.10.0'

# Then choose your preferred paginator from the following:
gem 'kaminari'
gem 'will_paginate'

# Finally...
gem 'api-pagination'

Configuration (optional)

By default, api-pagination will detect whether you're using Kaminari or WillPaginate, and name headers appropriately. If you want to change any of the configurable settings, you may do so:

ApiPagination.configure do |config|
  # If you have both gems included, you can choose a paginator.
  config.paginator = :kaminari # or :will_paginate

  # By default, this is set to 'Total'
  config.total_header = 'X-Total'

  # By default, this is set to 'Per-Page'
  config.per_page_header = 'X-Per-Page'

  # Optional: set this to add a header with the current page number.
  config.page_header = 'X-Page'

  # Optional: what parameter should be used to set the page option
  config.page_param = :page
  # or
  config.page_param do |params|

  # Optional: what parameter should be used to set the per page option
  config.per_page_param = :per_page
  # or
  config.per_page_param do |params|


In your controller, provide a pageable collection to the paginate method. In its most convenient form, paginate simply mimics render:

class MoviesController < ApplicationController
  # GET /movies
  def index
    movies = Movie.all # Movie.scoped if using ActiveRecord 3.x

    paginate json: movies

  # GET /movies/:id/cast
  def cast
    actors = Movie.find(params[:id]).actors

    # Override how many Actors get returned. If unspecified,
    # params[:per_page] (which defaults to 25) will be used.
    paginate json: actors, per_page: 10

This will pull your collection from the json or xml option, paginate it for you using params[:page] and params[:per_page], render Link headers, and call ActionController::Base#render with whatever you passed to paginate. This should work well with ActiveModel::Serializers. However, if you need more control over what is done with your paginated collection, you can pass the collection directly to paginate to receive a paginated collection and have your headers set. Then, you can pass that paginated collection to a serializer or do whatever you want with it:

class MoviesController < ApplicationController
  # GET /movies
  def index
    movies = paginate Movie.all

    render json:

  # GET /movies/:id/cast
  def cast
    actors = paginate Movie.find(params[:id]).actors, per_page: 10

    render json:

Note that the collection sent to paginate must respond to your paginator's methods. This is typically fine unless you're dealing with a stock Array. For Kaminari, Kaminari.paginate_array will be called for you behind-the-scenes. For WillPaginate, you're out of luck unless you call require 'will_paginate/array' somewhere. Because this pollutes Array, it won't be done for you automatically.


With Grape, paginate is used to declare that your endpoint takes a :page and :per_page param. You can also directly specify a :max_per_page that users aren't allowed to go over. Then, inside your API endpoint, it simply takes your collection:

class MoviesAPI < Grape::API
  format :json

  desc 'Return a paginated set of movies'
  get do
    # This method must take an ActiveRecord::Relation
    # or some equivalent pageable set.
    paginate Movie.all

  route_param :id do
    desc "Return one movie's cast, paginated"
    # Override how many Actors get returned. If unspecified,
    # params[:per_page] (which defaults to 25) will be used.
    # There is no default for `max_per_page`.
    paginate per_page: 10, max_per_page: 200
    get :cast do
      paginate Movie.find(params[:id]).actors


Then curl --include to see your header-based pagination in action:

$ curl --include 'https://localhost:3000/movies?page=5'
HTTP/1.1 200 OK
Link: <http://localhost:3000/movies?page=1>; rel="first",
  <http://localhost:3000/movies?page=173>; rel="last",
  <http://localhost:3000/movies?page=6>; rel="next",
  <http://localhost:3000/movies?page=4>; rel="prev"
Total: 4321
Per-Page: 10
# ...

A Note on Kaminari and WillPaginate

api-pagination requires either Kaminari or WillPaginate in order to function, but some users may find themselves in situations where their application includes both. For example, you may have included ActiveAdmin (which uses Kaminari for pagination) and WillPaginate to do your own pagination. While it's suggested that you remove one paginator gem or the other, if you're unable to do so, you must configure api-pagination explicitly:

ApiPagination.configure do |config|
  config.paginator = :will_paginate

If you don't do this, an annoying warning will print once your app starts seeing traffic. You should also configure Kaminari to use a different name for its per_page method (see

Kaminari.configure do |config|
  config.page_method_name = :per_page_kaminari
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