publication Liquid tag

publication.rb

# Copyright 2015 Michael D. Ekstrand.
# Licensed under the MIT License http://md.ekstrandom.net/copyright
require 'nokogiri'

module Jekyll
  class PubCiteTag < Liquid::Tag
    def initialize(tag_name, text, tokens)
      super
      @key = text.strip
      @kpath = "research/pubs/#{@key}/index.md"
      if tag_name == 'publication'
          @wrap = false
      elsif tag_name == 'pubcite'
          @wrap = true
      end
    end

    def render(context)
      site = context.registers[:site]
      page = site.pages.find { |pg|
        pg.path == @kpath
      }
      if page.nil?
        nil
      else
        parsed = Nokogiri::HTML::DocumentFragment.parse page.transform
        cite = parsed.at_css('.citation')
        if cite.nil?
          cite = parsed.at_css('p')
        end
        if not cite.nil?
          link = cite.at_css('a[href="#"]')
          if not link.nil?
            url = page.url
            if @wrap
              url = site.config['url'] + url
            end
            link['href'] = url
          end
          if @wrap
            cite.to_html
          else
            cite.children.to_html
          end
        else
          print parsed
          "<strong>Bad citation #{@key}</strong>"
        end
      end
    end
  end
end

Liquid::Template.register_tag('publication', Jekyll::PubCiteTag)
Liquid::Template.register_tag('pubcite', Jekyll::PubCiteTag)