Jekyll tag cloud / tag pages plugin

tag_cloud_tag.rb

module Jekyll
  class TagCloudTag < Liquid::Tag
    safe = true
    
    def initialize(tag_name, text, tokens)
      super
    end

    def render(context)
      html = ""
      tags = context.registers[:site].tags
      avg = tags.inject(0.0) {|memo, tag| memo += tag[1].length} / tags.length
      weights = Hash.new
      tags.each {|tag| weights[tag[0]] = tag[1].length/avg}
      tags.each do |tag, posts|
        html << "<span style='font-size: #{sprintf("%d", weights[tag] * 100)}%'><a href='/tags/#{tag}/'>#{tag}</a></span>\n"
      end
      html
    end
  end
end

Liquid::Template.register_tag('tag_cloud', Jekyll::TagCloudTag)

tag_page.rb

module Jekyll
  class TagPage
    include Convertible
    attr_accessor :site, :pager, :name, :ext
    attr_accessor :basename, :dir, :data, :content, :output

    def initialize(site, tag, posts)
      @site = site
      @tag = tag
      self.ext = '.html'
      self.basename = 'index'
      self.content = <<-EOS
{% for post in page.posts %}
<h3>{{ post.date | date: "%A %d.%m." }} &mdash; <a href="{{ post.url }}">{{ post.title }}</a></h3>

<p>{{ post.content | truncatewords: 20 }}</p>

<p>
{% if post.categories != empty %}
In {{ post.categories | array_to_sentence_string }}.
{% endif %}
{% if post.tags != empty %}
Tagged {{ post.tags | array_to_sentence_string }}.
</p>
{% endif %}
{% endfor %}
EOS
      self.data = {
        'layout' => 'default',
        'type' => 'tag',
        'title' => "Posts tagged #{@tag}",
        'posts' => posts
      }
    end

    def render(layouts, site_payload)
      payload = {
        "page" => self.to_liquid,
        "paginator" => pager.to_liquid
      }.deep_merge(site_payload)
      do_layout(payload, layouts)
    end

    def url
      File.join("/tags", @tag, "index.html")
    end

    def to_liquid
      self.data.deep_merge({
                             "url" => self.url,
                             "content" => self.content
                           })
    end

    def write(dest_prefix, dest_suffix = nil)
      dest = dest_prefix
      dest = File.join(dest, dest_suffix) if dest_suffix
      path = File.join(dest, CGI.unescape(self.url))
      FileUtils.mkdir_p(File.dirname(path))
      File.open(path, 'w') do |f|
        f.write(self.output)
      end
    end

    def html?
      true
    end
  end
end

tag_page_generator.rb

module Jekyll
  class TagPageGenerator < Generator
    safe true

    def generate(site)
      site.tags.each do |tag, posts|
        site.pages << TagPage.new(site, tag, posts)
      end
    end
  end
end

Ooh! This is awesome. Thank you!

Is their a tutorial available for this somewhere? or maybe even if you could add some comments to the files as to how to actually use it that would be great. Currently this plugin does not work for me. Nothing is being generated.

To get this to work w/ ruby 2.1.3 & jekyll 2.4.0, I had to change the calls to foo.deep_merge(xxx) to Utils.deep_merge_hashes(foo,xxx). I don't really know any ruby, just following the discussion here:
moshen/jekyll-asset_bundler#22
and this patch:
moshen/jekyll-asset_bundler@d8c2211

For Jekyll 2.5.3, change the line class TagPage in tag_page.rb with class TagPage < Page in addition to @squito's comment to get rid of the Error: undefined method 'destination' for #<Jekyll::TagPage:0x000000020a3730>.

for tag_cloud_tag.rb, why not use a layout / include

{% assign all_tags = site.tags|size %}
<div class="tagcloud">{% for tag in site.tags %}
    {% assign tag_name = tag|first %}
    {% assign tag_count = tag|last|size %}
    {% assign tag_avg = tag_count | div: all_tags %}
    <span class="tag" style="font-size: {{ tag_avg | times: 100 }}%;">{{ tag_name }}</span>{% if false %} ({{ tag_count }}){% endif %}
{% endfor %}</div>

Works for me, and you can, as you can probably see; have a tag count added to data attribute or echoed out etc...

RE: links, it's a lovely concept, but I think the links should be a separate plugin to the tag cloud itself, as it actually needs to generate pages, and also, it probably needs a /tags/ folder, so feel free to modify my category listing page plugin, which does the same for category pages.

Better Jekyll Category Pages

Is this compatible with Jekyll 3?