How to specify list[Schema] response with a different response statuses?

[XCanG]

There is currently some problem with that, if I had something like 200 and 403 responses I could write:

@router.get("/url", response={200: SomeSchema, 403: OtherSchema}, auth=...)
def some_func(...):
    if no_perms: return 403, OtherSchema()
    ...
    data = ...
    return 200, [SomeSchema.model_validate(row) for row in data]

This will work fine, but if I use that:

@router.get("/url", response={200: list[SomeSchema], 403: OtherSchema}, auth=...)
def some_func(...):
    if no_perms: return 403, OtherSchema()
    ...
    data = ...
    return 200, [SomeSchema.model_validate(row) for row in data]

It will complain about schema, as if it doesn't have proper fields, but it actually does, since it initiated and validated by Schema that used Pydantic behind scene.

Additionally I find some loop problem here, I tried to specify tuple[...] and list[...] with different variations and if I put list[Literal[200] | list[SomeSchema]] it will try to revalidate same output until it crashes, in my case it did loop for 6453 times based on console output and then get InternalServerError and crashes.

[vitalik]

@XCanG hard to tell - you need to provide code for your SomeSchema and OtherSchema

[vitalik]

@XCanG can be ton of reasons - cannot guess..

on the other hand I see that you use model_validate in responses - you do not have to do this as django-ninja does that automatically

here is a minimal working example of your initial example:

from ninja import NinjaAPI, Schema

api = NinjaAPI()


class SomeSchema(Schema):
    id: int
    name: str

class OtherSchema(Schema):
    code: int
    message: str


@api.get("/url", response={200: list[SomeSchema], 403: OtherSchema})
def some_func(request, action: str = ''):
    if action == "show_403":
        return 403, {"code": 42, "message": "some message"}

    data = [{'id': 1, 'name': 'John'}, {'id': 2, 'name': 'Sarah'}]
    return 200, data

200 reponse:

403 path:

[vitalik]

model_validate also should work - but you do not have to do that as you will end up double validation:

@api.get("/url", response={200: list[SomeSchema], 403: OtherSchema})
def some_func(request, action: str = ''):
    if action == "show_403":
        return 403, OtherSchema(code=42, message="some message")

    data = [{'id': 1, 'name': 'John'}, {'id': 2, 'name': 'Sarah'}]
    return 200, [SomeSchema.model_validate(row) for row in data]

[XCanG]

Ah, didn't know about validation. But I used that because raw django response didn't work out by default.

Since your example seems to work for you, then I will provide more context. 403 used to block users without permissions so the model is actually very minimal (that one that I called OtherSchema):

class BooleanResponse(Schema):
    result: bool

But for the case of the list schemas, I use it in various parts of the code, so in all places it didn't work for me. But example of one schema:

class Payment_Request(Schema):
    amount: Decimal = Field(..., ge=10_000, le=1_000_000)
    company: str = Field(..., max_length=510)
    address: str = Field(..., max_length=510)
    inn: str = Field(..., max_length=510)
    kpp: str = Field(..., max_length=510)
    rsch: str = Field(..., max_length=510)
    bn: str = Field(..., max_length=510)
    kpsch: str = Field(..., max_length=510)
    bik: str = Field(..., max_length=510)
    phone: str = Field(..., max_length=20)
    email: str = Field(..., max_length=255)


class Seller_InvoiceDB(Payment_Request):
    id: int
    amount: Decimal
    seller: SellerDB
    date: datetime
    payment_confirmed: bool = Field(default=False)
    accepted_at: datetime | None = Field(default=None)
    accepted_by: UserDB | None = Field(default=None)

In this case it return {200: list[Seller_InvoiceDB], 403: BooleanResponse} and an example of endpoint:

@router.get(
    "/invoices/{seller_id}",
    response={200: list[Seller_InvoiceDB], 403: BooleanResponse},
    auth=header_key,
)
@paginate
def get_seller_invoices(
    request: HttpRequest,
    seller_id: int,
) -> tuple[Literal[200], Sequence[Seller_InvoiceDB]] | tuple[Literal[403], BooleanResponse]:
    if (extra := validate_permissions(request.user, (UserType.director, UserType.accountant))):
        return status.HTTP_403_FORBIDDEN, BooleanResponse(result=False)

    return status.HTTP_200_OK, [Seller_InvoiceDB.model_validate(inv) for inv in Seller_Invoice.objects.filter(seller_id=seller_id).order_by("-id")]

But I would say that mostly all this comes out to proper schema (OpenAPI and Swagger), rather than actual validation and this is the reason why I putting it in response in the first place.
There sometimes cases where I had to work with the data before proceed to return it to requester, so I would like to have some solution that prevent double validation if I already returning Pydantic schemas.

[vitalik]

@XCanG well I still do not understand from your description - what's the problem ? :)
Do you see some error ? do you need multiple statuses for your response ?

[vitalik]

Could you isolate some small example without lot of fields where you can reproduce the "crash" ?