~widelands-dev/widelands-website/django_staticfiles

from django.conf import settings

from django.core.cache import cache

from django.contrib.auth.models import User

from django.utils.deprecation import MiddlewareMixin

from django.contrib.auth import user_logged_out

from django.dispatch import receiver

ONLINE_THRESHOLD = getattr(settings, 'ONLINE_THRESHOLD', 60 * 15)

ONLINE_MAX = getattr(settings, 'ONLINE_MAX', 50)

def get_online_now(self):

    return User.objects.filter(id__in=self.online_now_ids or [])

@receiver(user_logged_out)

def logout(sender, **kwargs):

    try:

        cache.delete('online-%s' % kwargs['user'].id)

    except AttributeError:

        pass

class OnlineNowMiddleware(MiddlewareMixin):

    """Maintains a list of users who have interacted with the website recently.

    Their user IDs are available as ``online_now_ids`` on the request

    object, and their corresponding users are available (lazily) as the

    ``online_now`` property on the request object.

    """

    def process_request(self, request):

        # First get the index

        uids = cache.get('online-now', [])

        # Perform the multiget on the individual online uid keys

        online_keys = ['online-%s' % (u,) for u in uids]

        fresh = cache.get_many(online_keys).keys()

        online_now_ids = [int(k.replace('online-', '')) for k in fresh]

        # If the user is authenticated, add their id to the list

        if request.user.is_authenticated:

            uid = request.user.id

            # If their uid is already in the list, we want to bump it

            # to the top, so we remove the earlier entry.

            if uid in online_now_ids:

                online_now_ids.remove(uid)

            online_now_ids.append(uid)

            if len(online_now_ids) > ONLINE_MAX:

                del online_now_ids[0]

        # Attach our modifications to the request object

        request.__class__.online_now_ids = online_now_ids

        request.__class__.online_now = property(get_online_now)

        # Set the new cache

        cache.set('online-%s' % (request.user.pk,), True, ONLINE_THRESHOLD)

        cache.set('online-now', online_now_ids, ONLINE_THRESHOLD)