serve_files.rb

#!/usr/bin/env ruby -w

require 'rubygems'
require 'rack'
require 'rack/handler/webrick'
require 'optparse'

class App
  def self.root
    Dir.pwd
  end
  
  def self.file_server
    @file_server ||= Rack::File.new(root)
  end
  
  def self.call(env)
    path = env["PATH_INFO"]

    file_path = File.join(root, path)
    if File.file?(File.join(file_path, "index.html"))
      env["PATH_INFO"] = File.join(path, "index.html")
    end

    file_server.call(env)    
  end
end

options = {:Port => "8888"}

OptionParser.new do |o|
  o.on("-p PORT") { |port| options[:Port] = port }
  o.on("-h") { puts o; exit }
  o.parse!
end

fork do
  sleep 0.2
  system "open http://localhost:#{options[:Port]}/"
end

Rack::Handler::WEBrick.run(App, options)