python - FastAPI 请求中的不可哈希类型

Question

我正在使用 fastapi 编写 post-api。所需的请求格式为:

{
   "leadid":LD123,
   "parties":[
      {
         "uid":123123,
         "cust_name":"JOhn Doe",
      }, ...]}

python中的fastapi代码是:

class Customer(BaseModel):
    UID: str
    CustName: str

class PackageIn(BaseModel): 
    lead_id: str
    parties: Set[Customer]
    # threshold: Optional[int] = 85

app = FastAPI()

@app.post('/')
async def nm_v2(package:PackageIn):
    return {"resp":"Response"}

当我访问 SwaggerUI 提交响应时，错误是 “422 错误:无法处理的实体” .此外，SwaggerUI 文档指出

{
  "detail": [
    {
      "loc": [
        "body"
      ],
      "msg": "unhashable type: 'Customer'",
      "type": "type_error"
    }
  ]
}

我不知道如何为请求有效负载创建这个 dict() 结构而不创建一个名为 Customer 的单独的基于 pydantic 的类。请告诉我如何纠正错误。

Answer 1

Pytdantic BaseClass 不可散列。有一个discussion关于这个功能，我想它不会被实现。讨论中有解决方法，对于您的情况，您可以尝试以下操作:

from pydantic import BaseModel
from typing import Set


class MyBaseModel(BaseModel):
    def __hash__(self):  # make hashable BaseModel subclass
        return hash((type(self),) + tuple(self.__dict__.values()))


class Customer(MyBaseModel):  # Use hashable sublclass for your model
    UID: str
    CustName: str


class PackageIn(BaseModel):
    lead_id: str
    parties: Set[Customer]
    # threshold: Optional[int] = 85

data = {
    "lead_id": 'LD123',
    "parties": [
       {
           "UID": 123123,
           "CustName": "JOhn Doe",
       }]}

PackageIn.parse_obj(data) # This part fastapi will make on post request, just for test

> <PackageIn lead_id='LD123' parties={<Customer UID='123123' CustName='JOhn Doe'>}>