Django sessions: can you check for session data and set it in same view?

Question

When using Django sessions, is it good practice to see if session data has been previously set, and if not to set the initial session data, in the same view?

Will this cause major issues, for me or users, if users have their cookies disabled?

(The presence of test cookies has confused me a little. However if you used these you would not be able to record data about the page the user initially viewed.)

Below is an excerpt from my views.py file. In the view the user is visiting a page with a game on it.

If they have previously stored session data - and if first time viewing game - the view will modify session data to record the fact they have visited game. If they have no session data it will be initialised here for them.

def game(request, game_name):
    game = get_object_or_404(Game, web_name=game_name)
    c = { 'game': game }

    # game_votes is used to store if user has voted on game yet.
    # Also a key in dictionary indicates user has previously visited that game.
    game_votes = request.session.get('game_votes', False):
    if game_votes:
        if not game_votes.has_key(game_name):
            game_votes[game_name] = False
            request.session['game_votes'] = game_votes
            request.session.modified = True
        else:
            pass
    else: # I.e. no session was declared previously.
        request.session['game_votes'] = { game_name: False }
        request.session['sorting_choice'] = 'PO'
        request.session['ip_address'] = request.META['HTTP_X_FORWARDED_FOR']

    return render_to_response('game.html', c)

As this is the first time I've used Django, I wanted to know what glaring mistakes I have inadvertently made with regards to using sessions.

Thank you very much for your expertise and help :)

EDIT:

So just to check: if a user has cookies disabled, this doesn't create a new session entry in the database for every page he views? Right?

Answer 1

This is exactly right. Session data isn't stored in cookies - the cookie just stores the unique ID of the user's data in the session database.

One minor nit: don't use has_key - it has been discouraged in Python for years. Use in:

if game_name in game_votes:

Answer 2

It is perfectly fine to check for sessions in a single view and then set the variables in the same view - most of the time, if I am going to need this data in a few different views I'd make a private function (just with an underscore in front of the name) and call it and pass the request parameter to the function too, so it has access to the session data. Then in every view that needs access to session data, I make sure to call this function at the start so the data will always be available.