RSS2Twitter.rb

require 'rubygems'
require 'httparty'

FEED_URL              = 'http://cdevroe.com/category/mobile-photos/feed/'
CACHE_FILE          = './rss2twitter.cache'
TWITTER_USER        = 'user'
TWITTER_PASS        = 'pass'
TIMEOUT             = 12*60*60 # 12 hours in seconds

class WP; include HTTParty; format :xml; end

class Twitter
  include HTTParty
  base_uri 'http://twitter.com'
  basic_auth TWITTER_USER, TWITTER_PASS
end

cache     = []
new_cache = []

# Open cache file, creating it if it doesn't exist
f = File.open(CACHE_FILE, File::RDONLY|File::CREAT)

# Read file into cache array
f.each_line {|line| cache << line.strip}
f.close

# Loop through RSS items
WP.get(FEED_URL)['rss']['channel']['item'].each do |item|
  
  # Change guid into Colin's short url format
  url = item['guid'].gsub(/\?p=/, "p/")
  
  # Get post date
  time = Time.parse(item["pubDate"])
  
  # Check if it's postable: not cached and not outside of timeout
  if !cache.include?(url) && (Time.now - time) < TIMEOUT
    Twitter.post('/statuses/update.json', {
      :status => "Mobile Photo \"#{item['title']}\": #{url}"
    })
  end
  
  new_cache << url
end

# Update cache file
File.open(CACHE_FILE, File::WRONLY|File::TRUNC) do |file|
  file.puts new_cache.join("\n")
end