MultiplexingProxy.rb

require "rubygems"
require 'net/http'
require 'uri'

module WEBrick
  class HTTPRequest
    attr_writer :host, :port, :request_uri, :unparsed_uri, :request_line, :path
  end
end

class MultiplexingProxy < WEBrick::HTTPServer

  def initialize(options)
    super(options)
  end

  def service(req, res)
    puts "*" * 50
    dest = destination(req)
    puts "Destination: #{dest}"


    url = URI.parse(dest)
    post = Net::HTTP::Post.new(url.path)
    post.body = req.body
    post.set_content_type(req.content_type)
    response = Net::HTTP.new(url.host, url.port).start {|http| http.request(post) }
    case response
    when Net::HTTPSuccess, Net::HTTPRedirection
      # OK
    else
      response.error!
    end
  end

  def destination(req)    
    req.body.match(/<PartyName>(.*?)<\/PartyName>/)[1]
  end

end

s = MultiplexingProxy.new(:Port => 8099)
trap("INT") {s.shutdown}
s.start