Source code for cattrs.preconf.pyyaml

"""Preconfigured converters for pyyaml."""

from datetime import date, datetime
from functools import partial
from typing import Any, Type, TypeVar, Union

from yaml import safe_dump, safe_load

from .._compat import FrozenSetSubscriptable
from ..converters import BaseConverter, Converter
from ..strategies import configure_union_passthrough
from ..tuples import is_namedtuple, namedtuple_unstructure_factory
from . import validate_datetime, wrap

T = TypeVar("T")


[docs]def validate_date(v, _): if not isinstance(v, date): raise ValueError(f"Expected date, got {v}") return v
[docs]class PyyamlConverter(Converter):
[docs] def dumps(self, obj: Any, unstructure_as: Any = None, **kwargs: Any) -> str: return safe_dump(self.unstructure(obj, unstructure_as=unstructure_as), **kwargs)
[docs] def loads(self, data: str, cl: Type[T]) -> T: return self.structure(safe_load(data), cl)
[docs]def configure_converter(converter: BaseConverter): """ Configure the converter for use with the pyyaml library. * frozensets are serialized as lists * string enums are converted into strings explicitly * datetimes and dates are validated * typed namedtuples are serialized as lists .. versionchanged: 24.1.0 Add support for typed namedtuples. """ converter.register_unstructure_hook( str, lambda v: v if v.__class__ is str else v.value ) # datetime inherits from date, so identity unstructure hook used # here to prevent the date unstructure hook running. converter.register_unstructure_hook(datetime, lambda v: v) converter.register_structure_hook(datetime, validate_datetime) converter.register_structure_hook(date, validate_date) converter.register_unstructure_hook_factory(is_namedtuple)( partial(namedtuple_unstructure_factory, unstructure_to=tuple) ) configure_union_passthrough( Union[str, bool, int, float, None, bytes, datetime, date], converter )
[docs]@wrap(PyyamlConverter) def make_converter(*args: Any, **kwargs: Any) -> PyyamlConverter: kwargs["unstruct_collection_overrides"] = { FrozenSetSubscriptable: list, **kwargs.get("unstruct_collection_overrides", {}), } res = PyyamlConverter(*args, **kwargs) configure_converter(res) return res