在 Post 请求正文中发送列表值以验证 Pydantic 模型

Question

我正在使用 FastAPI、Pydantic、SQLAlchemy 和 Postgres 构建接收 post 请求并将数据存储在数据库中的服务。 Pydantic 模型中有一个 List，如下所示：

from typing import List
from pydantic import BaseModel, Field

class Note(base model):
    id: int
    title: str
    authors: List[str]

和table：

notes = Table(
    "notes",
    metadata,
    Column("id", Integer, primary_key=True),
    Column("title", String),
    Column("authors", ARRAY(String(50), dimensions=3)),
)

这是我执行 post 请求的方式，当没有 List 值时：

def post(payload: Note):
    query = questions.insert().values(title=payload.title)
    return database.execute(query=query)

Post 请求正文：

{
    "title": "some value"
}

而且效果很好。但是添加 List 值会因 Pydantic 的验证错误而中断它：

def post(payload: Note):
    query = questions.insert().values(title=payload.title, authors=payload.authors)
    return database.execute(query=query)

{
    "title": "some value",
    "authors": ["name1", "name2", "name3"]
}

value is not a valid list

type_error.list

如何更改 post 函数和请求正文，使其正常工作？

编辑：回溯：

ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/uvicorn/protocols/http/httptools_impl.py", line 385, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File "/usr/lib/python3/dist-packages/uvicorn/middleware/proxy_headers.py", line 45, in __call__
    return await self.app(scope, receive, send)
  File "/home/saeed/.local/lib/python3.8/site-packages/fastapi/applications.py", line 149, in __call__
    await super().__call__(scope, receive, send)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/applications.py", line 102, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 181, in __call__
    raise exc from None
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 159, in __call__
    await self.app(scope, receive, _send)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/exceptions.py", line 82, in __call__
    raise exc from None
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/exceptions.py", line 71, in __call__
    await self.app(scope, receive, sender)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/routing.py", line 550, in __call__
    await route.handle(scope, receive, send)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/routing.py", line 227, in handle
    await self.app(scope, receive, send)
  File "/home/saeed/.local/lib/python3.8/site-packages/starlette/routing.py", line 41, in app
    response = await func(request)
  File "/home/saeed/.local/lib/python3.8/site-packages/fastapi/routing.py", line 204, in app
    response_data = await serialize_response(
  File "/home/saeed/.local/lib/python3.8/site-packages/fastapi/routing.py", line 126, in serialize_response
    raise ValidationError(errors, field.type_)
pydantic.error_wrappers.ValidationError: 1 validation error for Note
response
  value is not a valid list (type=type_error.list)

Answer 1

我想通了。通过修复有错误的 respone_model 解决了问题，我为存储数据所做的一切都是正确的。

@router.post("/", response_model=Note, status_code=201)
def create_note(payload: Note):
    note_id = post(payload)
    response_object = {
        "id": note_id,
        "title": payload.title,
        "authors": payload.authors,
    }
    return response_object

Answer 2

@router.get("/fetchusuarios", response_model=List[providers.schemas.User])
async def fetchall_users(db:Session=Depends(get_db)):
    usuarios = db.query(models.usermodel.User).all()
    return usuarios

Answer 3

我在使用 Django-Ninja（基于 FastAPI）时遇到了同样的错误。原来我的装饰器是这样的：

@router.get('/apartment-sale-hanoi/', response=List[ApartmentSaleHanoiSchema])

我通过从响应模型中删除 List 来修复 value is not a valid list (type=type_error.list)，如下所示：

@router.get('/apartment-sale-hanoi/', response=ApartmentSaleHanoiSchema)

我返回的响应（显示为 JSON）是一个对象列表

response = ApartmentSaleHanoi.objects.all()

在 Post 请求正文中发送列表值以验证 Pydantic 模型

sending a list value in a Post request's body to validate Pydantic model

python

postgresql

sqlalchemy

pydantic

fastapi