Independent, sortable pagination for ruhoh.rb (plugin)

pagination.rb

module SortablePaginator
    # provides helpful metrics for the paginator and mustache templates
    def paginator_data
      per_page       = config["paginator"]["per_page"] rescue 5
      paginator_sort = config["paginator"]["sort"] rescue 'desc'
      current_page   = master.page_data['current_page'].to_i
      post_count     = all.length
      page_count     = (post_count.to_f/per_page).ceil

      if paginator_sort == 'asc'
        current_page = current_page.zero? ? page_count : current_page
        next_oldest  = (current_page == 1)          ? false : current_page - 1
        next_newest  = (current_page == page_count) ? false : current_page + 1
        offset       = post_count - ((current_page)*per_page)
        if offset < 0
          per_page = per_page + offset
          offset   = 0
        end
      else
        # descending pagination (old default)
        current_page = current_page.zero? ? 1 : current_page
        next_oldest  = (current_page == page_count) ? false : current_page + 1
        next_newest  = (current_page == 1)          ? false : current_page - 1
        offset       = (current_page-1)*per_page
      end

      # resulting data structure
      {
        'posts_per_page' => per_page,
        'post_count'     => post_count,
        'page_count'     => page_count,
        'url'            => config['paginator']['url'] || '',
        'this_page'      => {
           'number'           => current_page,
           'next_oldest_page' => next_oldest,
           'next_newest_page' => next_newest,
           'post_offset'      => offset,
         }
      }
    end


  # current_page is set via a compiler or previewer
  # in which it can discern what current_page to serve
    # current_page is set via a compiler or previewer
    # in which it can discern what current_page to serve
    def paginator
      data = paginator_data
      page_batch = all[ data['this_page']['post_offset'], data['posts_per_page'] ]
      raise "Page does not exist" unless page_batch
      page_batch
    end


  def paginator_navigation
    paginator_config = config["paginator"] || {}
    paginator_config_sort = paginator_config['sort'] || 'desc'
    page_count = all.length
    total_pages = (page_count.to_f/paginator_config["per_page"]).ceil
    current_page = master.page_data['current_page'].to_i
    current_page = current_page.zero? ? 1 : current_page

    pages = total_pages.times.map { |i|
      url = if i == (total_pages - 1) and paginator_config['sort'] == 'asc' \
              and paginator_config["root_page"]
              paginator_config["root_page"]
            elsif i.zero? and paginator_config_sort == 'desc' \
              and paginator_config["root_page"]
              paginator_config["root_page"]
            else
              "#{paginator_config["url"]}/#{i+1}"
            end
      {
        "url" => ruhoh.to_url(url),
        "name" => "#{i+1}",
        "is_active_page" => (i+1 == current_page)
      }
    }
    pages
  end
end

module Ruhoh::Resources::Pages
  class Compiler
    # helper method
    def pagination_render( view )
        resource_name =  @collection.resource_name
        Ruhoh::Friend.say { cyan "#{resource_name} paginator: page_data: (#{view.page_data} )
" }
        FileUtils.mkdir_p File.dirname(view.compiled_path)
        File.open(view.compiled_path, 'w:UTF-8') { |p| p.puts view.render_full }
        Ruhoh::Friend.say { green "  > #{view.page_data['url']}" }
    end

    def pagination
      config = @collection.config["paginator"] || {}
      resource_name = @collection.resource_name
        Ruhoh::Friend.say { cyan "#{resource_name} paginator: page_data: (#{view.page_data} )
" }
        FileUtils.mkdir_p File.dirname(view.compiled_path)
        File.open(view.compiled_path, 'w:UTF-8') { |p| p.puts view.render_full }
        Ruhoh::Friend.say { green "  > #{view.page_data['url']}" }
    end

    def pagination
      config = @collection.config["paginator"] || {}
      resource_name = @collection.resource_name
      if config["enable"] == false
        Ruhoh::Friend.say { yellow "#{resource_name} paginator: disabled - skipping." }
        return
      end

      pages_count = @collection.all.length
      total_pages = (pages_count.to_f/config["per_page"]).ceil

      Ruhoh::Friend.say { cyan "#{resource_name} paginator: (#{total_pages} pages)" }

      total_pages.times.map { |i|
        # if a root page is defined we assume it's getting compiled elsewhere.
        if not (config.key? 'sort' and config['sort'] == 'asc') and \
          (i.zero? && config["root_page"])
          next
        end

        url = "#{config["url"]}/#{i+1}"
        view = @ruhoh.master_view({"resource" => resource_name})
        view.page_data = {
          "layout" => config["layout"],
          "current_page" => (i+1),
          "total_pages" => total_pages,
          "url" => @ruhoh.to_url(url)
        }
        pagination_render( view )

        # in ascending pagination, 'root_page' is a copy of the latest page.
        if i == ( total_pages - 1 ) and config["root_page"]
          view.page_data['url'] = "/#{ config['root_page'] }"
          pagination_render( view )
        end
      }
    end
  end
end


Ruhoh::Resources::Pages::CollectionView.send(:include, SortablePaginator)
# TODO: figure out why .send doesn't seem to affect Compiler
#Ruhoh::Resources::Pages::Compiler.send(:include, SortableCompilerPaginator)

snippet-from-config.yml

# ...in the middle of config.yml:
#
# paginate the 'posts' collection ASC, but keep the collection sorting DESC
posts:
  sort: ["date", "desc"]
  permalink: "/:categories/:title/"
  permalink: "/:year/:month/:day/:title/"
  summary_lines: 20
  latest: 5
  rss:
    enable: true
    limit: 10
  paginator:
    enable: true
    sort:   'asc'
    url: "/posts/page/"
    per_page: 10
#
# ...and so on

snippet-from-pagination.feature

# I've set up my ruhoh project with its own features/ directory so I can
# test new plugins, etc

  Scenario: Paginating asc by date, Collection sorting desc by date.
    Given a config file with values:
      | essays | { "paginator" : { "per_page" : 2, "sort" : "asc" }, "sort": [ "date", "desc"
 ] } |
      And the file "essays/post-1.md" with body:
        """
        ---
        date: "2010-12-01"
        ---
        <post>1</post>
        """
      And the file "essays/post-2.md" with body:
        """
        ---
        date: "2010-12-02"
        ---
        <post>2</post>
        """
      And the file "essays/post-3.md" with body:
        """
        ---
        date: "2011-01-01"
        ---
        <post>3</post>
        """
      And the file "essays/post-4.md" with body:
        """
        ---
        date: "2011-08-11"
        ---
        <post>4</post>
        """
      And the file "essays/post-5.md" with body:
        """
        ---
        date: "2012-01-02"
        ---
        <post>5</post>
        """
    When I compile my site
    Then my compiled site should have the file "essays/index/1/index.html"
      And this file should contain the content node "post|21
    Then my compiled site should have the file "essays/index/2/index.html"
      And this file should contain the content node "post|43"
    Then my compiled site should have the file "essays/index/3/index.html"
      And this file should contain the content node "post|5"