from __future__ import annotations
import dataclasses
from dataclasses import replace
from typing import TYPE_CHECKING, Generic, TypeVar
import msgspec.inspect
from msgspec import NODEFAULT, Struct, structs
from litestar.dto.base_dto import AbstractDTO
from litestar.dto.data_structures import DTOFieldDefinition
from litestar.dto.field import DTO_FIELD_META_KEY, DTOField, extract_dto_field
from litestar.plugins.core._msgspec import kwarg_definition_from_field
from litestar.types.empty import Empty
if TYPE_CHECKING:
from collections.abc import Collection, Generator
from typing import Any
from litestar.typing import FieldDefinition
__all__ = ("MsgspecDTO",)
T = TypeVar("T", bound="Struct | Collection[Struct]")
def _default_or_empty(value: Any) -> Any:
return Empty if value is NODEFAULT else value
def _default_or_none(value: Any) -> Any:
return None if value is NODEFAULT else value
[docs]
class MsgspecDTO(AbstractDTO[T], Generic[T]):
"""Support for domain modelling with Msgspec."""
[docs]
@classmethod
def generate_field_definitions(cls, model_type: type[Struct]) -> Generator[DTOFieldDefinition, None, None]:
msgspec_fields = {f.name: f for f in structs.fields(model_type)}
inspect_fields: dict[str, msgspec.inspect.Field] = {
field.name: field
for field in msgspec.inspect.type_info(model_type).fields # type: ignore[attr-defined]
}
property_fields = cls.get_property_fields(model_type)
for key, field_definition in cls.get_model_type_hints(model_type).items():
kwarg_definition, extra = kwarg_definition_from_field(inspect_fields[key])
field_definition = dataclasses.replace(field_definition, kwarg_definition=kwarg_definition)
field_definition.extra.update(extra)
dto_field = extract_dto_field(field_definition, field_definition.extra)
field_definition.extra.pop(DTO_FIELD_META_KEY, None)
msgspec_field = msgspec_fields[key]
yield replace(
DTOFieldDefinition.from_field_definition(
field_definition=field_definition,
dto_field=dto_field,
model_name=model_type.__name__,
default_factory=_default_or_none(msgspec_field.default_factory),
),
default=_default_or_empty(msgspec_field.default),
name=key,
)
for key, property_field in property_fields.items():
if key.startswith("_"):
continue
yield DTOFieldDefinition.from_field_definition(
property_field,
model_name=model_type.__name__,
default_factory=None,
dto_field=DTOField(mark="read-only"),
)
[docs]
@classmethod
def detect_nested_field(cls, field_definition: FieldDefinition) -> bool:
return field_definition.is_subclass_of(Struct)
Litestar