add: offset / limit based pagination

Gemfile

@@ -37,6 +37,8 @@ gem "kamal", require: false
 # Add HTTP asset caching/compression and X-Sendfile acceleration to Puma [https://github.com/basecamp/thruster/]
 gem "thruster", require: false
 
+gem "pagy", "~> 9.3"
+
 # Use Active Storage variants [https://guides.rubyonrails.org/active_storage_overview.html#transforming-images]
 # gem "image_processing", "~> 1.2"
 
@@ -60,4 +62,4 @@ group :test do
   # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
   gem "capybara"
   gem "selenium-webdriver"
-end
+end

Gemfile.lock

@@ -182,6 +182,7 @@ GEM
     nokogiri (1.16.7-x86_64-linux)
       racc (~> 1.4)
     ostruct (0.6.1)
+    pagy (9.3.1)
     parallel (1.26.3)
     parser (3.3.6.0)
       ast (~> 2.4.1)
@@ -366,6 +367,7 @@ DEPENDENCIES
   importmap-rails
   jbuilder
   kamal
+  pagy (~> 9.3)
   propshaft
   puma (>= 5.0)
   rails (~> 8.0.0)

app/controllers/application_controller.rb

@@ -1,4 +1,5 @@
 class ApplicationController < ActionController::Base
   # Only allow modern browsers supporting webp images, web push, badges, import maps, CSS nesting, and CSS :has.
   allow_browser versions: :modern
+  include Pagy::Backend
 end

app/controllers/products_controller.rb

@@ -2,7 +2,7 @@ class ProductsController < ApplicationController
 
   # GET /products or /products.json
   def index
-    @products = Product.all
+    @pagy, @products = pagy(Product.all)    
   end
 
 end

app/helpers/application_helper.rb

@@ -1,2 +1,3 @@
 module ApplicationHelper
+	include Pagy::Frontend
 end

app/views/products/index.html.erb

@@ -8,5 +8,7 @@
   <% @products.each do |product| %>
     <%= render product %>    
   <% end %>
+
+  <%== pagy_nav(@pagy) %>
 </div>
 

config/initializers/pagy.rb

@@ -0,0 +1,220 @@
+# frozen_string_literal: true
+
+# Pagy initializer file (9.3.1)
+# Customize only what you really need and notice that the core Pagy works also without any of the following lines.
+# Should you just cherry pick part of this file, please maintain the require-order of the extras
+
+
+# Pagy Variables
+# See https://ddnexus.github.io/pagy/docs/api/pagy#variables
+# You can set any pagy variable as a Pagy::DEFAULT. They can also be overridden per instance by just passing them to
+# Pagy.new|Pagy::Countless.new|Pagy::Calendar::*.new or any of the #pagy* controller methods
+# Here are the few that make more sense as DEFAULTs:
+# Pagy::DEFAULT[:limit]       = 20                    # default
+# Pagy::DEFAULT[:size]        = 7                     # default
+# Pagy::DEFAULT[:ends]        = true                  # default
+# Pagy::DEFAULT[:page_param]  = :page                 # default
+# Pagy::DEFAULT[:count_args]  = []                    # example for non AR ORMs
+# Pagy::DEFAULT[:max_pages]   = 3000                  # example
+
+
+# Extras
+# See https://ddnexus.github.io/pagy/categories/extra
+
+
+# Legacy Compatibility Extras
+
+# Size extra: Enable the Array type for the `:size` variable (e.g. `size: [1,4,4,1]`)
+# See https://ddnexus.github.io/pagy/docs/extras/size
+# require 'pagy/extras/size'   # must be required before the other extras
+
+
+# Backend Extras
+
+# Arel extra: For better performance utilizing grouped ActiveRecord collections:
+# See: https://ddnexus.github.io/pagy/docs/extras/arel
+# require 'pagy/extras/arel'
+
+# Array extra: Paginate arrays efficiently, avoiding expensive array-wrapping and without overriding
+# See https://ddnexus.github.io/pagy/docs/extras/array
+# require 'pagy/extras/array'
+
+# Calendar extra: Add pagination filtering by calendar time unit (year, quarter, month, week, day)
+# See https://ddnexus.github.io/pagy/docs/extras/calendar
+# require 'pagy/extras/calendar'
+# Default for each calendar unit class in IRB:
+# >> Pagy::Calendar::Year::DEFAULT
+# >> Pagy::Calendar::Quarter::DEFAULT
+# >> Pagy::Calendar::Month::DEFAULT
+# >> Pagy::Calendar::Week::DEFAULT
+# >> Pagy::Calendar::Day::DEFAULT
+#
+# Uncomment the following lines, if you need calendar localization without using the I18n extra
+# module LocalizePagyCalendar
+#   def localize(time, opts)
+#     ::I18n.l(time, **opts)
+#   end
+# end
+# Pagy::Calendar.prepend LocalizePagyCalendar
+
+# Countless extra: Paginate without any count, saving one query per rendering
+# See https://ddnexus.github.io/pagy/docs/extras/countless
+# require 'pagy/extras/countless'
+# Pagy::DEFAULT[:countless_minimal] = false   # default (eager loading)
+
+# Elasticsearch Rails extra: Paginate `ElasticsearchRails::Results` objects
+# See https://ddnexus.github.io/pagy/docs/extras/elasticsearch_rails
+# Default :pagy_search method: change only if you use also
+# the searchkick or meilisearch extra that defines the same
+# Pagy::DEFAULT[:elasticsearch_rails_pagy_search] = :pagy_search
+# Default original :search method called internally to do the actual search
+# Pagy::DEFAULT[:elasticsearch_rails_search] = :search
+# require 'pagy/extras/elasticsearch_rails'
+
+# Headers extra: http response headers (and other helpers) useful for API pagination
+# See https://ddnexus.github.io/pagy/docs/extras/headers
+# require 'pagy/extras/headers'
+# Pagy::DEFAULT[:headers] = { page: 'Current-Page',
+#                            limit: 'Page-Items',
+#                            count: 'Total-Count',
+#                            pages: 'Total-Pages' }     # default
+
+# Keyset extra: Paginate with the Pagy keyset pagination technique
+# See https://ddnexus.github.io/pagy/docs/extras/keyset
+# require 'pagy/extras/keyset'
+
+# Meilisearch extra: Paginate `Meilisearch` result objects
+# See https://ddnexus.github.io/pagy/docs/extras/meilisearch
+# Default :pagy_search method: change only if you use also
+# the elasticsearch_rails or searchkick extra that define the same method
+# Pagy::DEFAULT[:meilisearch_pagy_search] = :pagy_search
+# Default original :search method called internally to do the actual search
+# Pagy::DEFAULT[:meilisearch_search] = :ms_search
+# require 'pagy/extras/meilisearch'
+
+# Metadata extra: Provides the pagination metadata to Javascript frameworks like Vue.js, react.js, etc.
+# See https://ddnexus.github.io/pagy/docs/extras/metadata
+# you must require the JS Tools internal extra (BEFORE the metadata extra) ONLY if you need also the :sequels
+# require 'pagy/extras/js_tools'
+# require 'pagy/extras/metadata'
+# For performance reasons, you should explicitly set ONLY the metadata you use in the frontend
+# Pagy::DEFAULT[:metadata] = %i[scaffold_url page prev next last]   # example
+
+# Searchkick extra: Paginate `Searchkick::Results` objects
+# See https://ddnexus.github.io/pagy/docs/extras/searchkick
+# Default :pagy_search method: change only if you use also
+# the elasticsearch_rails or meilisearch extra that defines the same
+# Pagy::DEFAULT[:searchkick_pagy_search] = :pagy_search
+# Default original :search method called internally to do the actual search
+# Pagy::DEFAULT[:searchkick_search] = :search
+# require 'pagy/extras/searchkick'
+# uncomment if you are going to use Searchkick.pagy_search
+# Searchkick.extend Pagy::Searchkick
+
+
+# Frontend Extras
+
+# Bootstrap extra: Add nav, nav_js and combo_nav_js helpers and templates for Bootstrap pagination
+# See https://ddnexus.github.io/pagy/docs/extras/bootstrap
+# require 'pagy/extras/bootstrap'
+
+# Bulma extra: Add nav, nav_js and combo_nav_js helpers and templates for Bulma pagination
+# See https://ddnexus.github.io/pagy/docs/extras/bulma
+# require 'pagy/extras/bulma'
+
+# Pagy extra: Add the pagy styled versions of the javascript-powered navs
+# and a few other components to the Pagy::Frontend module.
+# See https://ddnexus.github.io/pagy/docs/extras/pagy
+# require 'pagy/extras/pagy'
+
+# Multi size var used by the *_nav_js helpers
+# See https://ddnexus.github.io/pagy/docs/extras/pagy#steps
+# Pagy::DEFAULT[:steps] = { 0 => 5, 540 => 7, 720 => 9 }   # example
+
+
+# Feature Extras
+
+# Gearbox extra: Automatically change the limit per page depending on the page number
+# See https://ddnexus.github.io/pagy/docs/extras/gearbox
+# require 'pagy/extras/gearbox'
+# set to false only if you want to make :gearbox_extra an opt-in variable
+# Pagy::DEFAULT[:gearbox_extra] = false               # default true
+# Pagy::DEFAULT[:gearbox_limit] = [15, 30, 60, 100]   # default
+
+# Limit extra: Allow the client to request a custom limit per page with an optional selector UI
+# See https://ddnexus.github.io/pagy/docs/extras/limit
+# require 'pagy/extras/limit'
+# set to false only if you want to make :limit_extra an opt-in variable
+# Pagy::DEFAULT[:limit_extra] = false    # default true
+# Pagy::DEFAULT[:limit_param] = :limit   # default
+# Pagy::DEFAULT[:limit_max]   = 100      # default
+
+# Overflow extra: Allow for easy handling of overflowing pages
+# See https://ddnexus.github.io/pagy/docs/extras/overflow
+# require 'pagy/extras/overflow'
+# Pagy::DEFAULT[:overflow] = :empty_page    # default  (other options: :last_page and :exception)
+
+# Trim extra: Remove the page=1 param from links
+# See https://ddnexus.github.io/pagy/docs/extras/trim
+# require 'pagy/extras/trim'
+# set to false only if you want to make :trim_extra an opt-in variable
+# Pagy::DEFAULT[:trim_extra] = false # default true
+
+# Standalone extra: Use pagy in non Rack environment/gem
+# See https://ddnexus.github.io/pagy/docs/extras/standalone
+# require 'pagy/extras/standalone'
+# Pagy::DEFAULT[:url] = 'http://www.example.com/subdir'  # optional default
+
+# Jsonapi extra: Implements JSON:API specifications
+# See https://ddnexus.github.io/pagy/docs/extras/jsonapi
+# require 'pagy/extras/jsonapi'   # must be required after the other extras
+# set to false only if you want to make :jsonapi an opt-in variable
+# Pagy::DEFAULT[:jsonapi] = false  # default true
+
+# Rails
+# Enable the .js file required by the helpers that use javascript
+# (pagy*_nav_js, pagy*_combo_nav_js, and pagy_limit_selector_js)
+# See https://ddnexus.github.io/pagy/docs/api/javascript
+
+# With the asset pipeline
+# Sprockets need to look into the pagy javascripts dir, so add it to the assets paths
+# Rails.application.config.assets.paths << Pagy.root.join('javascripts')
+
+# I18n
+
+# Pagy internal I18n: ~18x faster using ~10x less memory than the i18n gem
+# See https://ddnexus.github.io/pagy/docs/api/i18n
+# Notice: No need to configure anything in this section if your app uses only "en"
+# or if you use the i18n extra below
+#
+# Examples:
+# load the "de" built-in locale:
+# Pagy::I18n.load(locale: 'de')
+#
+# load the "de" locale defined in the custom file at :filepath:
+# Pagy::I18n.load(locale: 'de', filepath: 'path/to/pagy-de.yml')
+#
+# load the "de", "en" and "es" built-in locales:
+# (the first passed :locale will be used also as the default_locale)
+# Pagy::I18n.load({ locale: 'de' },
+#                 { locale: 'en' },
+#                 { locale: 'es' })
+#
+# load the "en" built-in locale, a custom "es" locale,
+# and a totally custom locale complete with a custom :pluralize proc:
+# (the first passed :locale will be used also as the default_locale)
+# Pagy::I18n.load({ locale: 'en' },
+#                 { locale: 'es', filepath: 'path/to/pagy-es.yml' },
+#                 { locale: 'xyz',  # not built-in
+#                   filepath: 'path/to/pagy-xyz.yml',
+#                   pluralize: lambda{ |count| ... } )
+
+
+# I18n extra: uses the standard i18n gem which is ~18x slower using ~10x more memory
+# than the default pagy internal i18n (see above)
+# See https://ddnexus.github.io/pagy/docs/extras/i18n
+# require 'pagy/extras/i18n'
+
+
+# When you are done setting your own default freeze it, so it will not get changed accidentally
+Pagy::DEFAULT.freeze