Django: timezone.now() does not return current datetime

Question

Through a Django Rest Framework API, I am trying to serve all objects with a datetime in the future.

Problem is, once the server has started up, every time I submit the query, the API will serve all objects whose datetime is greater than the datetime at which the server started instead of the objects whose datetime is greater than the current time.

from django.utils import timezone

class BananasViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = Banana.objects.filter(date_and_time__gte=timezone.now())
    ...

Without any more luck, I also tried this variation:

import datetime as dt

class BananasViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = Banana.objects.filter(date_and_time__gte=
        timezone.make_aware(dt.datetime.now(), timezone.get_current_timezone())
    ...

Making a similar query in a Django shell correctly returns the objects up to date...

Answer 1

As the application code is currently written you're running timezone.now() once, when the class is first imported from anywhere.

Rather than apply the time queryset filtering on the class attribute itself, do so in the get_queryset() method so that it'll be re-evaluated on each pass.

Eg.

class BananasViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = Banana.objects.all()

    def get_queryset(self):
        cutoff = timezone.now()
        return self.queryset.filter(date_and_time__gte=cutoff)