Python - 其他模型中的 Pydantic 序列化器转换

Question

我想使用 Pydantic 2 将数据导出到 Kafka 子队列，并且需要在不同的模型中导出到 JSON。

例如我有以下对象：

class obj(BaseModel):
  resource: str
  resourceid: int
  resourceTime: datetime
  name: str
  option1: str
  option2: int
  
{
  "resource": "TEST",
  "resourceid": "1234",
  "resourceTime": "2024-09-03 00:00:00",
  "option1": "test",
  "option2": 23421,
  "name": "test"
}

但是我需要这样转储：

{
  "resource": "TEST",
  "name": "test,
  "resourceid": "1234",
  "resourceTime": "2024-09-03 00:00:00",
  "attributes": [
    {
      "name": "option1",
      "value": "test",
    },
    {
      "name": "option2",
      "value": 23421
    },
    {
      "name": "name",
      "value": "test"
    }
  ]    
}

有可能使用 Pydantic 的某些功能来实现这一点吗？

谢谢。

Answer 1

您可以使用

model_serializer

：

from datetime import datetime

from pydantic import BaseModel, model_serializer


class obj(BaseModel):
    resource: str
    resourceid: int
    resourceTime: datetime
    name: str
    option1: str
    option2: int

    @model_serializer(mode="wrap")
    def _serialize(self, handler):
        d = handler(self)
        d["resourceid"] = str(d["resourceid"])
        del d["option1"]
        del d["option2"]
        d["attributes"] = [
            {
                "name": "option1",
                "value": self.option1
            },
            {
                "name": "option2",
                "value": self.option2
            },
            {
                "name": "name",
                "value": self.name
            },
        ]
        return d

o = obj.model_validate(
    {
        "resource": "TEST",
        "resourceid": "1234",
        "resourceTime": "2024-09-03 00:00:00",
        "option1": "test",
        "option2": 23421,
        "name": "test"
    }
)

print(o.model_dump())