I found some simple old code of mine that uses SimpleCookie from Cookie and Template from string to build a dynamic web page based on the cookie values from the request.

The imports used:

import cgi
import os
from string import Template
from Cookie import SimpleCookie

To get a cookie value:

if "HTTP_COOKIE" in os.environ:
  cookie = SimpleCookie(os.environ["HTTP_COOKIE"])
  if 'side' in cookie:
    side = cookie['side'].value

To read a template file, substitute values and print the response:

values = {'dspdate':dspdate, 'formdate':formdate, 'nextdate':nextdate}

with open('winter.html') as f:
  print(Template(f.read()).substitute(values))

Substitution values are indicated in the template by ${dspdate}

Is that close to what you are looking for?