python - Django FilterSet AND(？)条件

Question

我正在创建一个应用程序，其中食物有多个成分，每个成分都有特定的值。我希望能够根据特定成分的值(value)过滤食物。

这是我的模型:

class Food(models.Model):
    id = models.AutoField(primary_key=True, db_column="id")
    name = models.CharField(max_length=150)
    product_type = models.CharField(max_length=150)

class Component(models.Model):

    id = models.AutoField(primary_key=True, db_column="id")
    name = models.CharField(max_length=150)
    value = models.FloatField()
    food = models.ForeignKey(Food, related_name='food_components', related_query_name='food_components')

然后我定义过滤器集和 View

import rest_framework_filters as filters

class ComponentFilter(filters.FilterSet):

    name = filters.CharFilter(name="name")
    val = filters.NumberFilter(name="value", distinct=True)
    minval = filters.NumberFilter(name="value", lookup_type="gte", distinct=True)
    maxval = filters.NumberFilter(name="value", lookup_type="lte", distinct=True)

    class Meta:
        model = Component

class FoodFilter(filters.FilterSet):

    name = filters.CharFilter(name='name')
    product_type = filters.CharFilter(name='product_type')
    components = filters.RelatedFilter(ComponentFilter, name='food_components')

    class Meta:
        model = Food

class FoodViewSet(viewsets.ModelViewSet):

    queryset = Food.objects.all()
    serializer_class = FoodSerializer
    filter_class = FoodFilter

我希望能够使用相关模型中的多个字段(结合两个参数)来过滤 View 集。类似于 http://whatever/foods/components__name=X&components__value=1会让我得到所有元素 X 值为 1 的食物。我正在使用 django-rest-framework-filters ( https://github.com/philipn/django-rest-framework-filters )

据我所知，由于所有食物都包含所有元素，因此 components__name 是无关紧要的，我将获得所有具有值为 1 的成分的食物。如何将两者结合起来？

提前致谢!

Answer 1

您需要创建一个新过滤器来处理 name、val 对 single Food 与给定的 Component 相关的对象:

class FoodComponentFilter(django_filters.Filter):
    def filter(self, qs, value):
        strs = value.split(',')
        if len(strs) != 2:
            raise Exception
        return qs.filter(
            food_components__in = Component.objects.filter(
                name=strs[0],
                value=float(strs[1])
            )
        )

在 FoodFilter 中实例化它:

class FoodFilter(filters.FilterSet):
   component_food_pair = FoodComponentFilter(name='dummy_field')
   [...]
   class Meta:
        model = Food
        fields = ('component_food_pair',[...])

然后，像这样使用它:

?component_food_pair=Foo,42.0