keyset.md

title	categories
Keyset	Backend Extra

Keyset Extra

Paginate with the Pagy keyset pagination technique.

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Overview

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

!ref Keyset Pagination: Concepts and Overview

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

require 'pagy/extras/keyset'

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

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

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

Variables

See the Pagy::Keyset variables

Methods

==- pagy_keyset(set, **vars)

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.

==- pagy_keyset_first_url(pagy, absolute: false)

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

==- pagy_keyset_next_url(pagy, absolute: false)

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

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