Synchronize two directories via fsevents and sftp

watch.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'rb-fsevent'
require 'net/sftp'

remote_host = 'host.goes.here'
remote_user = 'ubuntu'

Net::SFTP.start(remote_host, remote_user) do |sftp|

  fsevent = FSEvent.new
  fsevent.watch %w(Projects/contests Projects/commerce) do |directories|
    directories.each do |dir|
      remote_dir = dir.gsub "/Users/lachlan/Projects", "/home/#{remote_user}"
      remote_files = {}

      # collect remote mtimes
      sftp.dir.foreach remote_dir do |f| 
        remote_files[f.name] = f.attributes.mtime
      end

      # check local mtimes
      Dir.foreach(dir) do |local_file|
        f = "#{dir}#{local_file}"

        if File.file?(f) and (!remote_files.key? local_file or remote_files[local_file] < File.mtime(f).to_i)
          puts "Synchronizing #{f}"
          sftp.upload! f, "#{remote_dir}#{local_file}"
        end
      end
    end 
  end

  fsevent.run
end