watch.rb

#!/usr/bin/ruby
require 'wunderbar/opal-jquery'
require 'nokogumbo'

_html do
  _head do
    _title 'Various stats'
  end

  _body do
    _table do
      _tr do
        _td 'Opal gem version'
        _td.opal '...'
      end
      _tr do
        _td 'Gumbo-parser last update'
        _td.gumbo '...'
      end
      _tr do
        _td 'Nokogumbo downloads'
        _td.nokogumbo '...'
      end
    end
  end

  _script do
    %w(opal gumbo nokogumbo).each do |field|
      HTTP.post(nil, payload: {field: field}) do |response|
        $document.find('.' + field).text = response.json
      end
    end
  end
end

_json do
  if @field == 'opal'
    _ Nokogiri::HTML5.get('http://rubygems.org/gems/opal').
       at('.title h3').text
  elsif @field == 'gumbo'
    _ Nokogiri::HTML5.
      get('https://github.com/google/gumbo-parser/commits/master').
      at('.authorship time')['datetime']
  elsif @field == 'nokogumbo'
    _ Nokogiri::HTML5.get('http://rubygems.org/gems/nokogumbo').
      search('.downloads strong').last.text
  end
end