howisobamadoing.com / howisromneydoing.com

howisobamadoing.rb

# howisobamadoing.com / howisromneydoing.com
# (c) justinouellette.com MMXII

require 'rubygems'
require 'sinatra'

CACHE_TIME = 3600 # one hour
OBAMA_DATA_PATH = 'obama.txt'
ROMNEY_DATA_PATH = 'romney.txt'

get '/' do
  
  # are we obama or romney?
    @romney = request.env['SERVER_NAME'].include?('romney')
    data_file_path = @romney ? ROMNEY_DATA_PATH : OBAMA_DATA_PATH
  
  # get the data for the first time if necessary
    update_data unless File.exists?(data_file_path)
  
  # how old is the data?
    data_file = File.new(data_file_path)
    lmt = data_file.mtime
    modified_seconds_ago = Time.new.to_i - lmt.to_i
  
  # update the data if it's too old
    if modified_seconds_ago > CACHE_TIME
      data_file.close
      update_data
      data_file = File.new(data_file_path)
    end
  
  # get the number
    @number = data_file.read.to_i
    data_file.close

  # http headers for cache control
    expires(CACHE_TIME - modified_seconds_ago)
    etag(lmt.to_s + data_file_path)
    last_modified(lmt)
  
  # hc svnt dracones
    "The chance of #{@romney ? 'Romney' : 'Obama'} winning is #{@number}%"

end

def update_data
  
  # get fivethirtyeight and find the interesting js file
    html_538 = `curl -s fivethirtyeight.blogs.nytimes.com`
    js_match = /dataUrl: "(.+top\.js)/.match(html_538)
    return unless js_match
  
  # get the interesting js file and find our numbers
    js_538 = `curl -s #{js_match[1]}`
    forecast_match = /forecast":\[\["[\d|-]+",[\d|\.]+,[\d|\.]+,([\d|\.]+),([\d|\.]+)/.match(js_538)
    return unless forecast_match

  # round the numbers and write them to disk
    `echo #{forecast_match[1].to_f.round} > #{OBAMA_DATA_PATH}`
    `echo #{forecast_match[2].to_f.round} > #{ROMNEY_DATA_PATH}`

end