gistfile1.rb

require 'rubygems'
require 'tmail'
require 'rest_client'

DESTINATION = ARGV.first || 'http://localhost:4567/posts'

class Message
  def self.receive(raw)
    message = parse(raw)
    params = {}
    [:to, :from, :subject].each{|f| params[f] = message.send(f)}
    resource = RestClient::Resource.new DESTINATION
    resource.post params
  end
  
  def self.parse(raw)
    TMail::Mail.parse(raw)
  end
end

Message.receive(STDIN.read)