tag_generator.rb

module Jekyll
  # Base class for the tag pages with all the shared behaviour
  class BaseTagPage < Page
    def initialize(site, base, dir)
      @site = site
      @base = base
      @dir = dir
      @name = 'index.html'
      self.process @name
      self.read_yaml File.join(base, '_layouts'), layout_page
    end

    # Implement this function in child classes
    # Expected to return a string containing the filename of the layout in _layouts
    def layout_page
      raise
    end
  end

  # Represents a specific tag page
  class TagPage < BaseTagPage
    def initialize(site, base, dir, tag)
      super(site, base, dir)
      self.data['tag'] = tag
      self.data['title'] = "Tag: " + tag
    end

    def layout_page
      'tag_page.html'
    end
  end

  # Generate a page for every tag
  class TagPageGenerator < Generator
    safe true

    def generate(site)
      if site.layouts.has_key? 'tag_page'
        dir = site.config['tag_dir'] || 'tag'
        site.tags.keys.each do |tag|
          write_tag_page(site, File.join(dir, tag.to_url), tag)
        end
      end
    end

    private

    def write_tag_page(site, dir, tag)
      page = TagPage.new(site, site.source, dir, tag)
      page.render(site.layouts, site.site_payload)
      page.write(site.dest)

      site.pages << page
    end
  end

  # Represents a page with all the tags
  class TagIndexPage < BaseTagPage
    def layout_page
      'tag_index.html'
    end
  end

  # Generates a page with all tags
  class TagIndexGenerator < Generator
    safe true

    def generate(site)
      if site.layouts.has_key? 'tag_index'
        dir = site.config['tag_index_dir'] || 'tags'
        write_tag_index(site, dir)
      end
    end

    private

    def write_tag_index(site, dir)
      page = TagIndexPage.new(site, site.source, dir)
      page.render(site.layouts, site.site_payload)
      page.write(site.dest)
      site.pages << page
    end
  end

    # Adds some extra filters used during the tag creation process.
    module Filters

      # Outputs a list of tags as comma-separated <a> links. This is used
      # to output the tag list for each post on a tag page.
      #
      #  +tags+ is the list of tags to format.
      #
      # Returns string
      #
      def tag_links(tags)
        tags = tags.sort!.map { |c| tag_link c }

        case tags.length
        when 0
          ""
        when 1
          tags[0].to_s
        else
          "#{tags[0...-1].join(', ')}, #{tags[-1]}"
        end
      end

      # Outputs a single tag as an <a> link.
      #
      #  +tag+ is a tag string to format as an <a> link
      #
      # Returns string
      #
      def tag_link(tag)
        dir = @context.registers[:site].config['tag_dir']
        "<a class='category' href='/#{dir}/#{tag.to_url}/'>#{tag}</a>"
      end

      # Outputs the post.date as formatted html, with hooks for CSS styling.
      #
      #  +date+ is the date object to format as HTML.
      #
      # Returns string
      def date_to_html_string(date)
        result = '<span class="month">' + date.strftime('%b').upcase + '</span> '
        result += date.strftime('<span class="day">%d</span> ')
        result += date.strftime('<span class="year">%Y</span> ')
        result
      end

    end
end