Sam Stephenson’s PaginationHelper for Rails interacts with ActiveRecord to ensure only a single page of data is loaded from the database and handles links to the other hidden pages. It’s a helper script that I’ve been using everywhere.

Helpers are mixins which add methods to the Rails controller and templates. Install a helper by copying it into /app/helpers/ in your Rails application. Here’s an updated PaginationHelper I’ve updated for Rails 0.90: pagination_helper.rb.

Load the helper at the beginning of a controller like this:

 class BlogPostsController < ApplicationController
   helper :pagination
   include PaginationHelper
 end

Not all helpers require the include statement. We’ll be using the Paginator class inside the helper, so it’s necessary in this case.

Now, you’ll need to use the Paginator in tandem with ActiveRecord#find to grab a single page of data for display:

 @pages = Paginator.new self, BlogPosts.count, 30, @params['page'].to_i
 @posts = BlogPosts.find nil, "post_time DESC", @pages.current.to_sql

My remix of the PaginationHelper (linked above) also features a simple method for generating a window of page links. The Paginator#window_links method accepts your template’s view object and a window size.

I’ve stored my paginator links in a partial called /app/views/partial/_pager.rb:

 <div id="counter">
   Displaying <%= @pages.current.first_item %>
   - <%= @pages.current.last_item %>
   of <%= @pages.item_count %> &nbsp; &nbsp;

   <%= link_to( h('< Previous'), @pages.current.previous.to_link ) + " | " if
     @pages.current.previous %>
   <%= @pages.window_links( self, 4 ) %>
   <%= " | " + link_to( h('Next >'), @pages.current.next.to_link ) if
     @pages.current.next %>
 </div>