Summary

There are requirements for "create many" or "update many" endpoints that may involve processing a list of objects. Currently, the DTOs have a limitation in that they cannot receive data as a list of DTO instances. Would it be considered to have this feature included?

Basic Example

from dataclasses import dataclass
from datetime import date
from typing import Annotated
from litestar import Litestar, post
from litestar.dto import DataclassDTO, DTOConfig, DTOData

@dataclass
class Author:
    id: int
    name: str
    dob: date

AuthorWrite = DataclassDTO[Annotated[Author, DTOConfig({"id"})]]

@post("/", dto=AuthorWrite, return_dto=None)
async def create_many(data: DTOData[list[Author]]) -> list[Author]:
    # expected: list of dicts
    # current: empty {}
    print(data.as_builtins())

    # expected: being able to iterate over `data`
    # create instances of the DTO validated data.
    # current: TypeError: 'DTOData' object is not iterable
    return [i.create_instance(id=1) for i in data]

app = Litestar([create_many])

Drawbacks and Impact

Without this feature being natively supported, one has to resort to writing separate classes for receiving the data. This, to me, doesn't fully utilize the potential of DTOs.

@dataclass
class AuthorCreate:
    name: str
    dob: date

Unresolved questions

If this feature is under consideration, I will leave these points for the maintainers to consider:

• Should the DTOData instance be iterable if a list of objects is passed?
• Should some other method be added, such as data.create_instances()?
• How will kwargs be passed to this if data.create_instances is chosen? data.create_instance(id=1) vs data.create_instances([{'id': 1}])?