Kaminari

A Scope & Engine based, clean, powerful, customizable and sophisticated paginator for modern web app frameworks and ORMs

Features

Clean

Does not globally pollute Array, Hash, Object or AR::Base.

Easy to Use

Just bundle the gem, then your models are ready to be paginated. No configuration required. Don't have to define anything in your models or helpers.

Simple Scope-based API

Everything is method chainable with less "Hasheritis". You know, that's the modern Rails way. No special collection class or anything for the paginated values, instead using a general AR::Relation instance. So, of course you can chain any other conditions before or after the paginator scope.

Customizable Engine-based I18n-aware Helpers

As the whole pagination helper is basically just a collection of links and non-links, Kaminari renders each of them through its own partial template inside the Engine. So, you can easily modify their behaviour, style or whatever by overriding partial templates.

ORM & Template Engine Agnostic

Kaminari supports multiple ORMs (ActiveRecord, DataMapper, Mongoid, MongoMapper), multiple web frameworks (Rails, Sinatra, Grape), and multiple template engines (ERB, Haml, Slim).

Modern

The pagination helper outputs the HTML5 <nav> tag by default. Plus, the helper supports Rails unobtrusive Ajax.

Supported Versions

• Ruby 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 3.0, 3.1, 3.2, 3.3

• Rails 4.1, 4.2, 5.0, 5.1, 5.2, 6.0, 6.1, 7.0, 7.1, 7.2, 8.0

• Sinatra 1.4, 2.0

• Haml 3+

• Mongoid 3+

• MongoMapper 0.9+

• DataMapper 1.1.0+

Installation

To install kaminari on the default Rails stack, just put this line in your Gemfile:

gem 'kaminari'

Then bundle:

% bundle

If you're building non-Rails or non-ActiveRecord app and want the pagination feature on it, please take a look at Other Framework/Library Support section.

Query Basics

The page Scope

To fetch the 7th page of users (default per_page is 25)

User.page(7)

Note: pagination starts at page 1, not at page 0 (page(0) will return the same results as page(1)).

Kaminari does not add an order to queries. To avoid surprises, you should generally include an order in paginated queries. For example:

User.order(:name).page(7)

You can get page numbers or page conditions by using below methods.

User.count                     #=> 1000
User.page(1).limit_value       #=> 20
User.page(1).total_pages       #=> 50
User.page(1).current_page      #=> 1
User.page(1).next_page         #=> 2
User.page(2).prev_page         #=> 1
User.page(1).first_page?       #=> true
User.page(50).last_page?       #=> true
User.page(100).out_of_range?   #=> true

The per Scope

To show a lot more users per each page (change the per value)

User.order(:name).page(7).per(50)

Note that the per scope is not directly defined on the models but is just a method defined on the page scope. This is absolutely reasonable because you will never actually use per without specifying the page number.

Keep in mind that per internally utilizes limit and so it will override any limit that was set previously. And if you want to get the size for all request records you can use total_count method:

User.count                     #=> 1000
a = User.limit(5); a.count     #=> 5
a.page(1).per(20).size         #=> 20
a.page(1).per(20).total_count  #=> 1000

The padding Scope

Occasionally you need to pad a number of records that is not a multiple of the page size.

User.order(:name).page(7).per(50).padding(3)

Note that the padding scope also is not directly defined on the models.

Unscoping

If for some reason you need to unscope page and per methods you can call except(:limit, :offset)

users = User.order(:name).page(7).per(50)
unpaged_users = users.except(:limit, :offset) # unpaged_users will not use the kaminari scopes

Configuring Kaminari

General Configuration Options

You can configure the following default values by overriding these values using Kaminari.configure method.

default_per_page      # 25 by default
max_per_page          # nil by default
max_pages             # nil by default
window                # 4 by default
outer_window          # 0 by default
left                  # 0 by default
right                 # 0 by default
page_method_name      # :page by default
param_name            # :page by default
params_on_first_page  # false by default

There's a handy generator that generates the default configuration file into config/initializers directory. Run the following generator command, then edit the generated file.

% rails g kaminari:config

Changing page_method_name

You can change the method name page to bonzo or plant or whatever you like, in order to play nice with existing page method or association or scope or any other plugin that defines page method on your models.

Configuring Default per_page Value for Each Model by paginates_per

You can specify default per_page value per each model using the following declarative DSL.

class User < ActiveRecord::Base
  paginates_per 50
end

Configuring Max per_page Value for Each Model by max_paginates_per

You can specify max per_page value per each model using the following declarative DSL. If the variable that specified via per scope is more than this variable, max_paginates_per is used instead of it. Default value is nil, which means you are not imposing any max per_page value.

class User < ActiveRecord::Base
  max_paginates_per 100
end

Configuring max_pages Value for Each Model by max_pages

You can specify max_pages value per each model using the following declarative DSL. This value restricts the total number of pages that can be returned. Useful for setting limits on large collections.

class User < ActiveRecord::Base
  max_pages 100
end

Configuring params_on_first_page when using ransack_memory

If you are using the ransack_memory gem and experience problems navigating back to the previous or first page, set the params_on_first_page setting to true.

Controllers

The Page Parameter Is in params[:page]

Typically, your controller code will look like this:

@users = User.order(:name).page params[:page]

Views

The Same Old Helper Method

Just call the paginate helper:

<%= paginate @users %>

This will render several ?page=N pagination links surrounded by an HTML5 <nav> tag.

Helpers

The paginate Helper Method

<%= paginate @users %>

This would output several pagination links such as « First ‹ Prev ... 2 3 4 5 6 7 8 9 10 ... Next › Last ».

Specifying the "inner window" Size (4 by default)

<%= paginate @users, window: 2 %>

This would output something like ... 5 6 7 8 9 ... when 7 is the current page.

Specifying the "outer window" Size (0 by default)

<%= paginate @users, outer_window: 3 %>

This would output something like 1 2 3 ...(snip)... 18 19 20 while having 20 pages in total.

Outer Window Can Be Separately Specified by left, right (0 by default)

<%= paginate @users, left: 1, right: 3 %>

This would output something like 1 ...(snip)... 18 19 20 while having 20 pages in total.

Changing the Parameter Name (:param_name) for the Links

<%= paginate @users, param_name: :pagina %>

This would modify the query parameter name on each links.

Extra Parameters (:params) for the Links

<%= paginate @users, params: {controller: 'foo', action: 'bar', format: :turbo_stream} %>

This would modify each link's url_option. :controller and :action might be the keys in common.

Ajax Links (via rails-ujs, works with Rails < 7.2)

<%= paginate @users, remote: true %>

This would add data-remote="true" to all the links inside.

Specifying an Alternative Views Directory (default is kaminari/)

<%= paginate @users, views_prefix: 'templates' %>

This would search for partials in app/views/templates/kaminari. This option makes it easier to do things like A/B testing pagination templates/themes, using new/old templates at the same time as well as better integration with other gems such as cells.

The link_to_next_page and link_to_previous_page (aliased to link_to_prev_page) Helper Methods

<%= link_to_next_page @items, 'Next Page' %>

This simply renders a link to the next page. This would be helpful for creating a Twitter-like pagination feature.

The helper methods support a params option to further specify the link. If format needs to be set, include it in the params hash.

<%= link_to_next_page @items, 'Next Page', params: {controller: 'foo', action: 'bar', format: :turbo_stream} %>

The page_entries_info Helper Method

<%= page_entries_info @posts %>

This renders a helpful message with numbers of displayed vs. total entries.

By default, the message will use the humanized class name of objects in collection: for instance, "project types" for ProjectType models. The namespace will be cut out and only the last name will be used. Override this with the :entry_name parameter:

<%= page_entries_info @posts, entry_name: 'item' %>
#=> Displaying items 6 - 10 of 26 in total

The rel_next_prev_link_tags Helper Method

<%= rel_next_prev_link_