# Keyset Extra

Paginate with the Pagy keyset pagination technique.

# Overview

This is a tiny wrapper around the Pagy::Keyset API. Please refer to the class documentation for a fuller understanding of keyset pagination:

Keyset Pagination: Concepts and Overview

../../api/keyset/

This extra adds a pagy_keyset constructor method that can be used in your controllers and provides the automatic setting of the variables from the request params.

# Synopsis

pagy.rb (initializer)
require 'pagy/extras/keyset'

# useful optional extras for APIs
# require 'pagy/extras/limit'
# require 'pagy/extras/jsonapi'
# require 'pagy/extras/headers'

Controller (action)
# The set argument must be an uniquely ORDERED Activerecord Scope or Sequel Dataset 

# Minimal unique ordering with the primary key: it works fast out of the box 
set = Product.order(:id)
# See the Pagy::Keyset docs for other variables
@pagy, @records = pagy_keyset(set, **vars)

# Using same-direction order keyset (all :asc, or all :desc) 
# Notice the primary key added as the last column as a tie-breaker for uniqueness
set = Product.order(:brand, :model, :id)
# Allow using the tuple_comparison e.g. (brand, model, id) > (:brand, :model, :id)
@pagy, @records = pagy_keyset(set, tuple_comparison: true)

# Ordering with mixed-direction order keyset
set = Product.order(brand: :asc, model: :desc, id: :asc) 
@pagy, @records = pagy_keyset(set, **vars)

# URL Helpers
pagy_keyset_first_url_page(@pagy, absolute: true)
#=> "http://example.com/foo?page" 

pagy_keyset_next_url_page(@pagy)
#=> "/foo?page=eyJpZCI6MzB9"

# Variables

See the Pagy::Keyset variables

# Methods

This method is similar to the offset pagy method. It returns the pagy object (instance of Pagy::Keyset::ActiveRecord or Pagy::Keyset::Sequel, depending on the set class) and the array of records pulled from the DB.

Return the first page URL string. (See also the headers and jsonapi extras for more complete solutions)

Return the next page URL string or nil. (See also the headers and jsonapi extras for more complete solutions)