Let me know when the DMV line is short!

dmv_alerter.rb

#!/usr/bin/env ruby
# this script will scrape the CA DMV website for wait times,
# and if the wait is less than a certain threshold, it will
# alert you with an audible message (at least on OS X).

require 'open-uri'
require 'date'

# found from http://apps.dmv.ca.gov/web/fieldoffice.html?number=503
@branch_id = 503
@branch_name = 'San Francisco'
@url = 'http://apps.dmv.ca.gov/fodata/Output2.txt'
@alert_threshold = 10 # minutes

# fetch the latest wait times
# returns an array of [hours,minutes]
def fetch_wait_time
  data = open(@url).grep(/^#{@branch_id}/).first
  data.split(',').slice(1..-1)
end

# this gets called if the wait time is below a certain threshold
# (you could change it to send an email or anything you like)
def alert
  system("say 'DMV line is less than #{@alert_threshold} minutes long'")
end

loop do
  puts "🚙  " + DateTime.now.strftime('%D %I:%M%p')

  # pull down the wait time from the DMV website
  hours, minutes = fetch_wait_time

  puts "🏫  current wait time for #{@branch_name} office is #{hours}:#{minutes.rjust(2,'0')}"
  alert if hours.to_i < 1 && minutes.to_i < @alert_threshold

  puts "💤  sleeping for 5 minutes"
  sleep 5*60
  puts
end