server.rb

require 'socket'

NOT_FOUND = "HTTP/1.1 404 Not Found\nContent-Length: 9\n\nNot Found"
OK = "HTTP/1.1 200 OK\n"

socket = Socket.new(:INET, :STREAM)
sockaddr = Socket.sockaddr_in(11080, '127.0.0.1')
socket.bind(sockaddr)
socket.listen(5)

while client_socket = socket.accept[0]
  path = client_socket.readline.split[1]
  filename = File.expand_path("../#{path}", __FILE__)
  if File.file?(filename)
    contents = File.read(filename)
    client_socket.write(OK)
    client_socket.write("Content-Length: #{contents.size}\n\n")
    client_socket.write("#{contents}")
  else
    client_socket.write(NOT_FOUND)
  end
  client_socket.close
end