The environment dictionary will contain CGI like variables and will be populated by the server at each request from the client. This script will output the whole dictionary:

#! /usr/bin/env python

# Our tutorial's WSGI server
from wsgiref.simple_server import make_server

def application(environ, start_response):

   # Sorting and stringifying the environment key, value pairs
   response_body = ['%s: %s' % (key, value)
                    for key, value in sorted(environ.items())]
   response_body = '\n'.join(response_body)

   status = '200 OK'
   response_headers = [('Content-Type', 'text/plain'),
                  ('Content-Length', str(len(response_body)))]
   start_response(status, response_headers)

   return [response_body]

# Instantiate the WSGI server.
# It will receive the request, pass it to the application
# and send the application's response to the client
httpd = make_server(
   'localhost', # The host name.
   8051, # A port number where to wait for the request.
   application # Our application object name, in this case a function.
   )

# Wait for a single request, serve it and quit.
httpd.handle_request()

To run this script save it as environment.py, open the terminal, navigate to the directory where it was saved and type python environment.py at the command line.

If in Windows it is necessary first to add the path to python.exe to the system environment variable Path. By the way if you can use Linux in instead of Windows then do it. It will save some pain.

Now go to the browser and type at the address bar:

http://localhost:8051/