File watcher and live reload for Chrome on MAC OS

watcher.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>

trap("SIGINT") { exit }

if ARGV.length < 2
  puts "Usage: #{$0} watch_folder keyword"
  puts "Example: #{$0} . mywebproject"
  exit
end

dev_extension = 'dev'
filetypes = ['css','html','less','js']
watch_folder = ARGV[0]
keyword = ARGV[1]
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?
    hash = new_hash

    diff_hash.each do |df|
      puts "Detected change in #{df[0]}, refreshing"
      %x{osascript<<ENDGAME
        	tell application "Google Chrome"
            set windowList to every window
            repeat with aWindow in windowList
              set tabList to every tab of aWindow
              repeat with atab in tabList
                if (URL of atab contains "#{keyword}") then
                  tell atab to reload
                end if
              end repeat
            end repeat
          end tell
      }
    end
  end

  sleep 1
end