如何在DRF模型字段中仅显示和使用日期时间中的天数，并发送填充字段的请求

Question

我的模型

class Reservation(models.Model):
    user = models.ForeignKey(
        User, verbose_name='owner',
        on_delete=models.CASCADE,
        default=User.objects.all()[0].pk
    )
    RESERVATION_TYPES = (
        ('office', 'office'),
        ('workplace', 'workplace')
    )
    reservation_type = models.CharField(
        verbose_name='reservation type',
        choices=RESERVATION_TYPES,
        max_length=9,
        default='workplace'
    )
    office = models.ForeignKey(
        Office, verbose_name='offices for reservation',
        on_delete=models.CASCADE,
        default=Office.objects.all()[0].pk
    )
    workplaces = models.CharField(
        verbose_name='workplaces for reservation',
        blank=True,
        max_length=9
    )
    initial_day = models.DateField(
        verbose_name='days delta initial day',
        default=datetime.now() + timedelta(days=1)
    )
    days_delta = models.DurationField(
        verbose_name='days delta',
        null=True,
        default=timedelta(days=0)
    )

我的序列化器

class ReservationDetailSerializer(serializers.ModelSerializer):
    reservation_days = serializers.SerializerMethodField('get_reservation_days_list')

    class Meta:
        model = Reservation
        fields = (
            'id', 'reservation_type', 'office', 'workplaces',
            'initial_day', 'days_delta', 'reservation_days', 'user'
        )

    def get_reservation_days_list(self, reservation_model):
        initial_day = reservation_model.initial_day
        days_delta = reservation_model.days_delta
        reservation_days = []

        for delta in range(days_delta.days):
            reservation_days.append(date.isoformat(initial_day + timedelta(days=delta)))

        return reservation_days

    def validate(self, validated_data):
        validated_data['days_delta'] = validated_data['days_delta'] * 86400
        
        if validated_data['reservation_type'] == 'office':
            workplaces = []
            for workplace in Workplace.objects.all().filter(office=validated_data['office']):
                workplaces.append(workplace.pk)
            validated_data['workplaces'] = workplaces

        return validated_data

我的观点

class ReservationCreateView(generics.CreateAPIView):
    serializer_class = ReservationDetailSerializer
    permission_classes = (IsAuthenticated,)

请求

days_delta，以秒为单位，乘以86400 (一天中的秒)，将正确的间隔写入数据库。

days_delta，以秒为单位，乘以86400 (一天中的秒)，将正确的间隔写入数据库。

{
    "reservation_type": "office",
    "office": 1,
    "initial_day": "2020-12-31",
    "days_delta": 5,
    "user": 2
}

响应

days_delta需要等于5(仅限天)

{
    "id": 62,
    "reservation_type": "office",
    "office": 1,
    "workplaces": "[1, 2, 3, 4, 5]",
    "initial_day": "2020-12-31",
    "days_delta": "5 00:00:00",
    "reservation_days": [
        "2020-12-31",
        "2021-01-01",
        "2021-01-02",
        "2021-01-03",
        "2021-01-04"
    ],
    "user": 2
}

帮帮我，西德两天..。

Answer 1

您可以重写to_representation(self, value)方法。此方法以字段的目标作为值参数，并应返回用于序列化目标的表示形式。value参数通常是一个模型实例。

要从timedelta获得天数，请使用.days属性。

serializer.py

class ReservationDetailSerializer(serializers.ModelSerializer):
    reservation_days = serializers.SerializerMethodField('get_reservation_days_list')

    class Meta:
        model = Reservation
        fields = (
            'id', 'reservation_type', 'office', 'workplaces',
            'initial_day', 'days_delta', 'reservation_days', 'user'
        )

    def to_representation(self, instance):
        change_fields = ( 'days_delta', )
        data = super().to_representation(instance)

        for field in change_fields:
            try:
                data[field] = field.days
            except Exception as e:
                print(e)
        return data 
                
    def get_reservation_days_list(self, reservation_model):
        initial_day = reservation_model.initial_day
        days_delta = reservation_model.days_delta
        reservation_days = []

        for delta in range(days_delta.days):
            reservation_days.append(date.isoformat(initial_day + timedelta(days=delta)))

        return reservation_days


    def validate(self, validated_data):
        validated_data['days_delta'] = validated_data['days_delta'] * 86400

        if validated_data['reservation_type'] == 'office':
            workplaces = []
            for workplace in Workplace.objects.all().filter(office=validated_data['office']):
                workplaces.append(workplace.pk)
            validated_data['workplaces'] = workplaces

        return validated_data