Source code for cattrs.preconf.pyyaml

"""Preconfigured converters for pyyaml."""
from datetime import date, datetime
from typing import Any, Type, TypeVar, Union

from yaml import safe_dump, safe_load

from cattrs._compat import FrozenSetSubscriptable

from ..converters import BaseConverter, Converter
from ..strategies import configure_union_passthrough
from . import validate_datetime

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 """ 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) configure_union_passthrough( Union[str, bool, int, float, None, bytes, datetime, date], converter )
[docs]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