page_watcher.rb

require 'open-uri'
require 'nokogiri'
require 'twilio-ruby'
require 'spinning_cursor'

class Page

  attr_reader :etag, :last_modified, :data, :uri

  def initialize(uri)
    @uri = URI(uri)
  end

  def special_element
    doc = Nokogiri::HTML(@data)

    title, link, result = nil, nil, []
    doc.css(".Proddatalink a").each do |item|
      if !item.text.empty?
        result << "#{item.text}: #{@uri.hostname}/#{item['href']}"
      end
    end
    result
  end

  def request!(*args)
    begin
      open(@uri, *args) do |page|
        @etag = page.meta['etag'],
        @last_modified = page.meta['last-modified'],
        @data = page.read
      end
    rescue OpenURI::HTTPError => e
      raise e
    end
  end

end

class PageWatcher

  attr_reader :page

  def initialize(uri)
    @page = Page.new(uri)
    @page.request!
  end

  def updated?
    last_seen_value = @page.special_element
    @page.request!
    updated_value = @page.special_element

    diff = updated_value - last_seen_value

    notify(diff) unless diff.empty?
  end

  def notify(msg)
    account_sid = "YOUR_ACCOUNT_SID"
    auth_token = "YOUR_AUTH_TOKEN"
    client = Twilio::REST::Client.new account_sid, auth_token

    client.account.messages.create(
      :from => "TWILIO NUMBER",
      :to => "YOUR PHONE",
      :body => msg)

    puts "#{Time.now}:#{msg}"

    true
  end

end

SpinningCursor.run do
  banner "Working it"
  type :dots
  action do

    @page_watcher = PageWatcher.new('http://www.wiialerts.com/')

    # Update every 1-minutes
    600.times do
      SpinningCursor.set_banner "Checking for updates"
      @page_watcher.updated?
      SpinningCursor.set_banner "Sleeping"
      sleep 60
    end

  end

  message "Huh?! I'm awake!"

end