# gem install mongrel

# headerlog.rb
require 'rubygems'
require 'mongrel'
require 'logger'

class HeaderHandler < Mongrel::HttpHandler

 @@logger = Logger.new('headers.log')

 def process(request,response)
   response.start(200) do |head, out|
     head["Content-Type"] = "text/plain"
     @@logger.info request.params
   end
 end
end

server = Mongrel::HttpServer.new("127.0.0.1", "2222")
server.register("/", HeaderHandler.new)
server.register("/favicon.ico", Mongrel::Error404Handler.new(""))
server.run.join