serializers.py 文件源码

def get_date(self, instance):
        user = instance.id
        today = date.today()

        if instance.date is not None:
            return instance.date

        # calculate last reported day if no specific date is set
        max_absence_date = Absence.objects.filter(
            user=user, date__lt=today).aggregate(date=Max('date'))
        max_report_date = Report.objects.filter(
            user=user, date__lt=today).aggregate(date=Max('date'))

        last_reported_date = max(
            max_absence_date['date'] or date.min,
            max_report_date['date'] or date.min
        )

        instance.date = last_reported_date
        return instance.date