require 'socket'
require 'thread'

server = TCPServer.open(8080)

HEADER = <<-EOH
HTTP/1.1 200 OK
Content-Type: text/html; charset=ISO-8859-1

EOH

def respond_with(filename)
  HEADER + File.read(filename) if File.exists?(filename)
end

loop do
  Thread.start(server.accept) do |client|
    request = client.gets.split("\r\n").first.split(' ')
    case request[1]
    when '/'
      client.puts respond_with('./index.html')
    else
      filename = "./#{request[1]}"
      filename << '.html' unless filename =~ /\.\w{3,4}$/
      client.puts respond_with(filename)
    end
    client.close
  end
end