gistfile1.rb

config.action_controller.asset_host = Proc.new do |source, request|
  non_ssl_host = "http://asset#{source.hash % 4}.backpackit.com"
  ssl_host     = "https://asset1.backpackit.com"
  
  if request.ssl?
    case
    when source =~ /\.js$/
      ssl_host
    when request.headers["USER_AGENT"] =~ /(Safari)/
      non_ssl_host
    when request.headers["USER_AGENT"] =~ /Firefox/ && source =~ /^\/images/
      non_ssl_host
    else
      ssl_host
    end
  else
    non_ssl_host
  end  
end