Source code for cattrs.preconf.bson

"""Preconfigured converters for bson."""
from base64 import b85decode, b85encode
from datetime import date, datetime
from typing import Any, Type, TypeVar, Union

from bson import DEFAULT_CODEC_OPTIONS, CodecOptions, Int64, ObjectId, decode, encode

from cattrs._compat import AbstractSet, is_mapping
from cattrs.gen import make_mapping_structure_fn

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

T = TypeVar("T")

[docs]class Base85Bytes(bytes): """A subclass to help with binary key encoding/decoding."""
[docs]class BsonConverter(Converter):
[docs] def dumps( self, obj: Any, unstructure_as: Any = None, check_keys: bool = False, codec_options: CodecOptions = DEFAULT_CODEC_OPTIONS, ) -> bytes: return encode( self.unstructure(obj, unstructure_as=unstructure_as), check_keys=check_keys, codec_options=codec_options, )
[docs] def loads( self, data: bytes, cl: Type[T], codec_options: CodecOptions = DEFAULT_CODEC_OPTIONS, ) -> T: return self.structure(decode(data, codec_options=codec_options), cl)
[docs]def configure_converter(converter: BaseConverter): """ Configure the converter for use with the bson library. * sets are serialized as lists * byte mapping keys are base85-encoded into strings when unstructuring, and reverse * non-string, non-byte mapping keys are coerced into strings when unstructuring * a deserialization hook is registered for bson.ObjectId by default """ def gen_unstructure_mapping(cl: Any, unstructure_to=None): key_handler = str args = getattr(cl, "__args__", None) if args: if issubclass(args[0], str): key_handler = None elif issubclass(args[0], bytes): def key_handler(k): return b85encode(k).decode("utf8") return converter.gen_unstructure_mapping( cl, unstructure_to=unstructure_to, key_handler=key_handler ) def gen_structure_mapping(cl: Any): args = getattr(cl, "__args__", None) if args and issubclass(args[0], bytes): h = make_mapping_structure_fn(cl, converter, key_type=Base85Bytes) else: h = make_mapping_structure_fn(cl, converter) return h converter.register_structure_hook(Base85Bytes, lambda v, _: b85decode(v)) converter._unstructure_func.register_func_list( [(is_mapping, gen_unstructure_mapping, True)] ) converter._structure_func.register_func_list( [(is_mapping, gen_structure_mapping, True)] ) converter.register_structure_hook(ObjectId, lambda v, _: ObjectId(v)) configure_union_passthrough( Union[str, bool, int, float, None, bytes, datetime, ObjectId, Int64], converter ) # 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_unstructure_hook(date, lambda v: v.isoformat()) converter.register_structure_hook(date, lambda v, _: date.fromisoformat(v))
[docs]def make_converter(*args: Any, **kwargs: Any) -> BsonConverter: kwargs["unstruct_collection_overrides"] = { AbstractSet: list, **kwargs.get("unstruct_collection_overrides", {}), } res = BsonConverter(*args, **kwargs) configure_converter(res) return res