Pydantic:如何用自定义属性名解析JSON

Question

如何定义json属性到属性名称不同的pydantic模型之间的映射?即:

# I want to parse thumbnailUrl into thumbnail
class ChatMessageAttachment(BaseModel):
id: str
thumbnail: Optional["str"] = None
external_data = {"id": "123", "thumbnailUrl": "www.google.es"}
chat_message = ChatMessageAttachment(**external_data)
print(chat_message) # >>>id='123' thumbnail=None

Answer 1

在Pydantic中，您可以为此使用别名。在下面的代码中，如果您也想要用原始thumbnail实例化对象，则只需要Configallow_population_by_field_name。如果在创建对象时只使用thumbnailUrl，则不需要它:

from pydantic import BaseModel, Field
from typing import Optional
class ChatMessageAttachment(BaseModel):
id: str
thumbnail: Optional["str"] = Field(None, alias="thumbnailUrl")
class Config:
allow_population_by_field_name = True

external_data = {"id": "123", "thumbnailUrl": "www.google.es"}
chat_message = ChatMessageAttachment(**external_data)
print(chat_message) 
#  id='123' thumbnail='www.google.es

您还可以使用allow_population_by_field_name:

external_data = {"id": "123", "thumbnail": "www.google.es"}
ChatMessageAttachment(**external_data)
# ChatMessageAttachment(id='123', thumbnail='www.google.es')