Ruby script to fetch user's latest update from Twitter (for Adium integration)

twitter.rb

## gets the latest Twitter update from a user
require 'rubygems'
require 'json'
require 'yaml'
require 'open-uri'

CONFIG_FILE = ENV["HOME"] + "/.twitter"
CACHE_FILE = "/tmp/.#{ENV["LOGNAME"]}_TwitterAdium.txt"
DEFAULTS = { 'interval' => 300, 'limit' => 3 }

unless File.exist?(CONFIG_FILE)
  File.open(CONFIG_FILE, 'w') do |config|
    config.write(<<-EOF)
    ## .twitter
    username:
    # in seconds:
    interval: #{DEFAULTS['interval']}
    # how many updates can be fetched at once while 
    # searching for an update that isn't an @-reply:
    limit: #{DEFAULTS['limit']}
    EOF
  end
end
config = DEFAULTS.merge YAML::load(open(CONFIG_FILE))

if config["username"].nil?
  system %(open #{CONFIG_FILE.inspect})
  puts "[Twitter Adium]: Please edit your ~/.twitter file to contain your username"
  exit(1)
end

if File.exist?(CACHE_FILE)
  status_id, status_text = File.read(CACHE_FILE).split(' ', 2)
  # is cache still fresh?
  if File.mtime(CACHE_FILE) > Time.now - config['interval']
    puts status_text
    exit(0)
  end
else
  status_id = status_text = nil
end

twitter_url = "http://twitter.com/statuses/user_timeline/#{config["username"]}.json?count=#{config['limit']}"
twitter_url += "&since_id=#{status_id}" if status_id
page = 1

begin
  updates = JSON.parse open(twitter_url + "&page=#{page}").read
  status = updates.find { |update| update["text"].index('@') != 0 }
  page += 1
end while status.nil? and updates.length > 0

if status
  status_text = status["text"]
  File.open(CACHE_FILE, 'w') { |f| f << status['id'] << ' ' << status_text }
end

puts status_text