utils.py 文件源码

def make_active_productlist_query(queryset):
    now = timezone.now()
    # Create a query for the set of products that MIGHT be active. Might
    # because they can be out of stock. Which we compute later
    active_candidates = (
        queryset
        .filter(
            Q(active=True)
            & (Q(deactivate_date=None) | Q(deactivate_date__gte=now)))
    )
    # This query selects all the candidates that are out of stock.
    candidates_out_of_stock = (
        active_candidates
        .filter(sale__timestamp__gt=F("start_date"))
        .annotate(c=Count("sale__id"))
        .filter(c__gte=F("quantity"))
        .values("id")
    )
    # We can now create a query that selects all the candidates which are not
    # out of stock.
    return (
        active_candidates
        .exclude(
            Q(start_date__isnull=False)
            & Q(id__in=candidates_out_of_stock)))