Fastapi中ResponseModel的设计

• 前言

  在我学习ruoyi-fastapi-backend开源项目的时候让我思考了一下关于responsemodel的设计

  在这个项目中swagger文档中的示例模型是这样的

#model
class Token(BaseModel):
    """
    token响应模型
    """
    access_token: str= Field(description='token信息')

#swagger示例
{
  "access_token": "string"
}

​ 并没有显示code或者其他的 而是单单显示该模型

​

这令我想转牛角尖 为什么不把code也给加上去呢

首先来看看在ruoyi-fastapi-backend项目中response使用的是一个工具类来动态组装response

class ResponseUtil:
    @classmethod
    def success(
        cls,
        msg: str = '操作成功',
        data: Optional[Any] = None,
        rows: Optional[Any] = None,
        dict_content: Optional[Dict] = None,
        model_content: Optional[BaseModel] = None
    )-> Response:
        """
        成功响应方法
        :param msg:     可选，自定义成功响应信息
        :param data:    可选，成功响应结果中属性为data的值
        :param rows:    可选，成功响应结果中属性为rows的值
        :param dict_content:    可选，dict类型，成功响应结果中自定义属性的值
        :param model_content:   可选，BaseModel类型，成功响应结果中自定义属性的值
        :return:
        """

        result = {'code': HttpStatusConstant.SUCCESS,'msg': msg}
        if data is not None:
            result['data'] = data
        if rows is not None:
            result['rows'] = rows
        if dict_content is not None:
            result.update(dict_content)
        if model_content is not None:
            result.update(model_content.model_dump(by_alias=True))

        result.update({'success': True, 'time': datetime.now()})

        return JSONResponse(status_code=status.HTTP_200_OK, content=jsonable_encoder(result))
    
#返回示例
@loginController.post(
    '/login3',
    response_model=Token1,
)
async def login3(xxx):
    responsemodel = Token1(access_token=jwt_token)
    return ResponseUtil.success(data=responsemodel)

response_model=Token1这样就会导致swagger中没有code、msg对应的pydantic模型

在示例文档中
{
  "access_token": "string"
}
#在实际请求时
{
  "code": 200,
  "msg": "操作成功",
  "data": {
    "access_token": "xxx"
  },
  "success": true,
  "time": "2025-02-05T01:54:30.779036"
}

所以我就自己设计了一下自己的方式

T = TypeVar('T')


class BaseResponse(BaseModel,Generic[T]):
    """
    响应模型基类 自定义响应模型应继承此类 eg:{code,msg,success,time,**T}
    """
    code: int = Field(default=None, description='响应状态码')
    msg: str = Field(default=None, description='响应信息')
    success: bool = Field(default=None, description='是否成功')
    time: datetime = Field(default=None, description='响应时间')
    data: T = Field(default=None,description='数据信息')

    @classmethod
    def ok(
            cls,
            data: Optional[Any] = None,
            rows: Optional[Any] = None,
            model_content: Optional[BaseModel] = None
    ):
        result = {}
        if model_content is not None:
            result.update(model_content.model_dump(by_alias=True))
        if rows is not None:
            result['rows'] = rows
        if data is not None:
            result['data'] = data
        result['code'] = HttpStatusConstant.SUCCESS
        result['msg'] = '操作成功'
        result['success'] = True
        result['time'] = datetime.now()
        return result

用这种方式既可以在swagger上面显示code的字段 也可以很方便的返回response

嵌套的方式response_model=BaseResponse[Token1] BaseResponse.ok(data=responsemodel)

class Token1(BaseModel):
    """
    token响应模型
    """
    access_token: str= Field(description='token信息')
    
@loginController.post(
    '/login2',
    response_model=BaseResponse[Token1],
)
async def login2():
    responsemodel = Token1(access_token=jwt_token)
    return BaseResponse.ok(data=responsemodel)
#swagger
{
  "code": 0,
  "msg": "string",
  "success": true,
  "time": "2025-02-04T19:33:33.929Z",
  "data": {
    "access_token": "string"
  }
}

Model作为请求体的方式

Model继承BaseResponse response_model=Token BaseResponse.ok(model_content=responsemodel)

class Token(BaseResponse):
    """
    token响应模型
    """
    access_token: str= Field(description='token信息')
    
@loginController.post(
    '/login',
    response_model=Token
)
async def login():
    responsemodel = Token(access_token=jwt_token)
    return BaseResponse.ok(model_content=responsemodel)
#swagger
{
  "code": 0,
  "msg": "string",
  "success": true,
  "time": "2025-02-04T19:33:33.926Z",
  "data": 1,
  "access_token": "string"
}