Storm timelapse

storm_timelapse.rb

url = "http://blitzortung.net/Images/image_b_pl.png"
ref = "http://blitzortung.net"
agent = "Internet Explorer 8.0"
interval = 10*60
sleep_interval = 20
next_download_t = Time.now.to_i

Dir.mkdir('data') unless File.exists?('data')

loop do
   # proper interval
  next_download_t = Time.now.to_i + interval
  # sleep to maintain proper interval
  sleep_time = next_download_t - Time.now.to_i

  while sleep_time > 0
    puts "sleeping #{sleep_time}"
    sleep_time -= sleep_interval
    sleep(sleep_interval)
  end
  puts "sleep end"

  t = Time.now.to_i
  dest = "data/storm_#{t}.png"
  command = "wget --dns-timeout=5 --connect-timeout=5 --read-timeout=5 --quiet --referer=\"#{ref}\" --user-agent=\"#{agent}\" --load-cookies data/cookies.txt --keep-session-cookies --save-cookies data/cookies.txt \"#{url}\" -O#{dest}"
  puts "downloading #{t}"
  `#{command}`
end