How to get JSON values and how to trace sessions??

[webmaster at terradon.nl]

Hi all, 
from python I post data to a webpage using urllib and can print that content.
See code below.
 
But now i am wondering how to trace sessions? it is needed for a multiplayer game, connected to a webserver. How do i trace a PHP-session? I suppose i have to save a cookie with the sessionID from the webserver? Is this possible with Python? Are their other ways to keep control over which players sends the gamedata?

Secondly, can i handle JSON values? I know how to create them serverside, but how do i handle that response in python?

Thank you very much for any answer!


Code:
import urllib.request
import urllib.parse

user = 'user'
pw = 'password'

login_url = 'http://www.xxxxxxxx.nl/test/index.php'

data = urllib.parse.urlencode({'user': user, 'pw': pw})
data = data.encode('utf-8')
# adding charset parameter to the Content-Type header.
request = urllib.request.Request(login_url)
request.add_header("Content-Type","application/x-www-form-urlencoded;charset=utf-8")

f = urllib.request.urlopen(request, data)
print(f.read().decode('utf-8'))