Watch for file changes and refresh your browser automatically

watch.rb

#!/usr/bin/env ruby
# watch.rb by Brett Terpstra, 2011 <http://brettterpstra.com>
# with credit to Carlo Zottmann <https://github.com/carlo/haml-sass-file-watcher>
# edited by Dave Arter to refresh Chrome using code suggested in Brett's original blog post: <http://brettterpstra.com/watch-for-file-changes-and-refresh-your-browser-automatically/>
# edited more by Steve Pike to not do any of that, and instead recompile coffee.
 
trap("SIGINT") { exit }
 
if ARGV.length < 1
  puts "Usage: #{$0} watch_folder"
  puts "Example: #{$0} ."
  exit
end
 
dev_extension = 'dev'
filetypes = ['coffee']
watch_folder = ARGV[0]
puts "Watching #{watch_folder} and subfolders for changes in project files..."
 
while true do
  files = []
  filetypes.each {|type|
    files += Dir.glob( File.join( watch_folder, "**", "*.#{type}" ) )
  }
  new_hash = files.collect {|f| [ f, File.stat(f).mtime.to_i ] }
  hash ||= new_hash
  diff_hash = new_hash - hash
 
  unless diff_hash.empty?
    sleep 0.5
    hash = new_hash
 
    diff_hash.each do |df|
      puts "Detected change in #{df[0]}, refreshing"
      %x{coffee -c #{ARGV[0]}}
    end
  end
 
  sleep 1
end