django - 创建自定义过滤器

Question

目前我的看法如下:

from rest_framework.permissions import AllowAny
from dynamic_rest.viewsets import DynamicModelViewSet
from django_filters.rest_framework import DjangoFilterBackend

from .models import Purchase
from .serializers import PurchaseSerializer


class PurchasesViewSet(DynamicModelViewSet):
    queryset = Purchase.objects.all()
    serializer_class = PurchaseSerializer
    permission_classes = (AllowAny,)
    filter_backends = (DjangoFilterBackend,)
    filter_fields = ('name', 'color')

这允许我按精确的名称和颜色进行过滤。

我的数据有一个日期字段(DateField类型)。我想按“季度”创建一个自定义过滤器，以便这种请求:

/purchases/?quarter=2018Q1

提供指定季度内带有日期字段的对象列表。请注意，quarter 不是模型字段。

创建这样一个自定义过滤器的方法是什么？

Answer 1

首先，您必须创建自定义过滤器以及过滤器类

import django_filters
from rest_framework.exceptions import ValidationError


class QuarterFilter(django_filters.Filter): # Custom Filter
    def get_quarter_range(self, quarter):
        if quarter == 1:
            return [1, 3]
        elif quarter == 2:
            return [4, 6]
        elif quarter == 3:
            return [7, 9]
        elif quarter == 4:
            return [10, 12]
        else:
            raise ValidationError("quarter value must be range from 1-4")

    <b>def filter(self, qs, value):
        """
        create your custom filtering logi here
        """
        # here the "value" will be the value parsed from URL params, ie "2018Q1"
        try:
            year, quarter = value.split("Q") # spliting the input to get year and quarter value
            qs = qs.filter(date__year=year)

            qs = qs.filter(date__month__range=self.get_quarter_range(quarter))
            return qs
        except:
            return qs</b>


class PurchaseFilter(django_filters.FilterSet): # Custom Filter Class
    <b>quarter = QuarterFilter()</b>

    class Meta:
        model = Purchase
        fields = ['name', 'color', <b>'quarter'</b>]

然后，在您的 View 类中使用 filterset_class 提及它属性。那么你的观点是这样的，

class PurchasesViewSet(DynamicModelViewSet):
    queryset = Purchase.objects.all()
    serializer_class = PurchaseSerializer
    permission_classes = (AllowAny,)
    filter_backends = (DjangoFilterBackend,)
    <b># filter_fields = ('name', 'color') ---- Remove this line of code
    filterset_class = PurchaseFilter</b>

注意
我不确定这一行，

qs = qs.filter(date__month__range=self.get_quarter_range(quarter))

但是，这就是在这种特殊情况下您需要进行过滤的方式。

希望这有帮助!!