Question

有两个模型，它们是通过这种方式定义的：

class ShoppingList(models.Model):
   id = models.CharField(max_length=40, primary_key=True)
   name = models.CharField(max_length=40)
   session_id = models.CharField(max_length=40)
   config_file = models.FileField(upload_to=upload_config_file)

   def __str__(self):
       return self.id


class FetchedData(models.Model):
    model_id = models.CharField(max_length=40)
    config_id = models.ForeignKey(BillOfMaterial, on_delete=models.CASCADE, default=0)
    config_name = models.CharField(max_length=40)

    def __str__(self):
        return self.model_id

并像这样序列化：

class FetchedDataSerializer(serializers.ModelSerializer):
   file_fields = serializers.SerializerMethodField()

   class Meta:
      model = FetchedData
      fields = ('model_id', 'config_id', 'config_name', 'file_fields')

   def get_file_fields(self, obj):
      print(obj)
   #  queryset = ShoppingList.objects.filter(config_file = obj)     ## (1)
      queryset = BillOfMaterial.objects.all()                       ## (2)
      return [ShoppingListSerializer(cf).data for cf in queryset]

建议我*在上面的序列化器中实现标记为（1）的解决方案，但是当它打开时，我得到的响应为空数组，例如：

[
    {
        "model_id": "6553",
        "config_id": "2322",
        "config_name": "Config No. 1",
        "file_fields": []
    }
]

同时，在选项（2）打开且选项（1）被注释掉的情况下，我得到了所有显示的实例：

[
    {
        "model_id": "6553",
        "config_id": "2322",
        "config_name": "Config No. 1",
        "file_fields": [
            {
                "id": "2322",
                "name": "First Example",
                "session_id": "9883",
                "config_file": "/uploads/2322/eq-example_7DQDsJ4.json"
            },
            {
                "id": "4544",
                "name": "Another Example",
                "session_id": "4376",
                "config_file": "/uploads/4544/d-jay12.json"
            }
        ]
    }
]

print(obj)方法始终提供一个model_id值。我猜它应该输出file_fields.id。

我应该如何重新构建这段代码，使其仅显示file_field与id匹配父级config_id的情况？

*这是此处描述的问题的后续内容：TypeError: 'FieldFile' object is not callable

Answer 1

在FetchedData模型中，我添加了此方法：

def config_link(self):
    return self.config_id.config_file

（它绑定了config_file模型中的ShoppingList）。

FetchedDataSerializer应该看起来像这样：

class FetchedDataSerializer(serializers.ModelSerializer):
    file_link = serializers.SerializerMethodField()

    class Meta:
        model = FetchedData
        fields = ('model_id', 'config_id', 'config_name', 'file_link')

    def get_file_link(self, obj):
        return obj.config_link()

嵌套的序列化程序无法获取正确的ID

1 个答案: