gistfile1.rb

require 'rubygems'
require 'sinatra'
require 'ruby2ruby'
require 'pony'
require 'uri'

def base64_url_decode(str)
  str += '=' * (4 - str.length.modulo(4))
  Base64.decode64(str.gsub("-", "+").gsub("_", "/"))
end

def base64_url_encode(str)
  Base64.encode64(str).gsub("+", "-").gsub("/", "_").gsub(/\s/, '').gsub('=', '')
end

def dumpstate(b)
  vars = eval("local_variables", b).reject{|v| v == '_' }
  state = {}
  vars.each do |var| 
    val = eval(var, b)
    begin
      Marshal::dump(val)
      state[var] = val
    rescue
    end
  end
  [base64_url_encode(Marshal::dump(state)), vars]
end

def loadstate(s, b)
  state = Marshal::load(base64_url_decode(s))
  state.each do |k,v|
    eval("#{k} = Marshal::load(#{Marshal::dump(v).inspect})", b)
  end
end

class EvalBug < Exception; end

def run(code)
  eval(code)
rescue EvalBug
  eval(code)
end

def sproc(b, &block)
  return nil unless block_given?

  c = Class.new
  c.class_eval do
    define_method :serializable, &block
  end
  s = Ruby2Ruby.translate(c, :serializable)
  dumped, vars = dumpstate(b)
  s.sub(/^def \S+(\(([^\)]*)\))?/, "loadstate(#{dumped.inspect}, binding); "+vars.map{|v| "#{v} rescue raise EvalBug; "}.join).sub(/end$/, '')
end

get '/print' do
  puts "hello"
  'ok'
end

get '/hi' do
  email = 'progrium@gmail.com'
  url = URI.parse("http://google.com/hello")
  code = sproc(binding) do
    Pony.mail(:to => email,
              :from => email,
              :subject => 'Howdy, Partna!',
              :body => url.to_s,
              :via => :sendmail)
    puts "#{email}: #{url}"
  end
  redirect '/run/'+base64_url_encode(code)
end

get '/run/:code' do
  code = base64_url_decode(params[:code])
  run(code)
  code
end