如何在Django REST Framework序列化程序中使用向后关系查找来检索多对多字段?

问题描述 投票:0回答:3

如果不正确,请更正我的标题。我的问题是我想从FinishType中检索nameProduct。我尝试了两种方法来实现此目的:first attemptsecond attempt。我在models.py中简化的相关模型:

class Product(models.Model):
    product_id = models.CharField(max_length=6)
    color = models.ForeignKey(ColorParent, on_delete=models.SET_NULL, null=True)
    collection = models.ForeignKey(ProductCollection, on_delete=models.SET_NULL, null=True)

    @property
    def get_distributors(self):
        return Distributor.objects.filter(distributor__products=self).count()

    def __str__(self):
        return self.product_id

class FinishType(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name

class ProductFinishType(models.Model):
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    market = models.ForeignKey(Market, on_delete=models.CASCADE)
    finish_types = models.ManyToManyField(FinishType)

    def __str__(self):
        return '%s - %s' % (self.product, self.market)

class ProductAlias(models.Model):
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    market = models.ForeignKey(Market, on_delete=models.CASCADE)
    name = models.CharField(max_length=50, null=True, blank=True)

    def __str__(self):
        return '%s - %s' % (self.product, self.name)

我的serializers.py

class ProductGridSerializer(serializers.ModelSerializer):
    name = serializers.SerializerMethodField(source='get_name')
    finishing = serializers.SerializerMethodField('get_finish_types')
    distributor = serializers.ReadOnlyField(source='get_distributors')

    @staticmethod
    def get_name(obj):
        return [pa.name for pa in obj.productalias_set.all()]

    @staticmethod
    def get_finish_types(obj):
        return [pft.name for pft in obj.productfinishtype_set.all().select_related('finish_types')]  # first attempt

    class Meta:
        model = Product
        fields = ['id', 'product_id', 'name', 'collection', 'finishing', 'distributor']

[首次尝试用于name字段,该字段获取ProductAliasname但给我这个错误:

/ api / product_grids /与select_related相关的字段名称无效:“ finish_types”。选择是:产品,市场

我第二次尝试的get_finish_types()

@staticmethod
def get_finish_types(obj):
    product_finish_types = obj.productfinishtype_set.all()
    response = ProductFinishTypeSerializer(product_finish_types, many=True, source='finish_types').data
    return response

它给了我整个对象数据:

{
      "id": 1,
      "product_id": "BQ1111",
      "name": [
            "White Stone"
      ],
      "collection": 1,
      "finishing": [
          {
              "id": 1,
              "product": 1,
              "market": 1,
              "finish_types": [
                  1,
                  3,
                  5
              ]
          }
      ],
      "distributor": 5
},

我想要的输出是这样的:

{
      "id": 1,
      "product_id": "BQ1111",
      "name": [
            "White Stone"
      ],
      "collection": 1,
      "finishing": [
            "Polished",
            "Carved",
            "Melted"
      ],
      "distributor": 5
},
python django django-rest-framework
3个回答
1
投票

FinishType创建序列化器,

class FinishTypeSerializer(serializers.ModelSerializer):
    class Meta:
        model = FinishType
        fields = ('name',)

并使用ProductGridSerializer将其连接到SerializerMethodField

class ProductGridSerializer(serializers.ModelSerializer):
    name = serializers.SerializerMethodField(source='get_name')    
    distributor = serializers.ReadOnlyField(source='get_distributors')
    finishing = serializers.SerializerMethodField()

    def get_finishing(self, product):
        qs = FinishType.objects.filter(productfinishtype__product=product)
        return FinishTypeSerializer(qs, many=True).data

    @staticmethod
    def get_name(obj):
        return [pa.name for pa in obj.productalias_set.all()]

    class Meta:
        model = Product
        fields = ['id', 'product_id', 'name', 'collection', 'finishing', 'distributor']

0
投票

FinishType创建序列化器:

class FinishTypeSerializer(serializers.ModelSerializer):
    class Meta:
        model = FinishType
        fields = ('name',)

然后扩展您的ProductGridSerializer

class ProductGridSerializer(serializers.ModelSerializer):
      finishing = FinishTypeSerializer(read_only=True, many=True)
      ...
      fields = ['id', 'product_id', 'name', 'collection', 'finishing', 'distributor']

0
投票

受@Arakkal Abu的queryset的启发,我尝试了第一次。FinishTypeSerializer中添加了serializers.py

class FinishTypeSerializer(serializers.ModelSerializer):
    class Meta:
        model = FinishType
        fields = ('name',)

ProductGridSerializer中的[serializers.py

class ProductGridSerializer(serializers.ModelSerializer):
    name = serializers.SerializerMethodField(source='get_name')
    finishing = serializers.SerializerMethodField(source='get_finishing')
    distributor = serializers.ReadOnlyField(source='get_distributors')

    @staticmethod
    def get_name(obj):
        return [pa.name for pa in obj.productalias_set.all()]

    @staticmethod
    def get_finishing(product):
        return [pft.name for pft in FinishType.objects.filter(productfinishtype__product=product)]

    class Meta:
        model = Product
        fields = ['id', 'product_id', 'name', 'collection', 'finishing', 'distributor']

JSON输出为:

{
     "id": 1,
     "product_id": "BQ1111",
     "name": [
           "White Stone"
     ],
     "collection": 1,
     "finishing": [
           "Polished",
           "Honed",
           "Carved"
     ],
     "distributor": 5
},
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