codec_options – Tools for specifying BSON codec options

Tools for specifying BSON codec options.

class bson.codec_options.CodecOptions(document_class=None, tz_aware=False, uuid_representation=0, unicode_decode_error_handler='strict', tzinfo=None, type_registry=None, datetime_conversion=DatetimeConversion.DATETIME)

Encapsulates options used encoding and / or decoding BSON.

The document_class option is used to define a custom type for use decoding BSON documents. Access to the underlying raw BSON bytes for a document is available using the RawBSONDocument type:

>>> from bson.raw_bson import RawBSONDocument
>>> from bson.codec_options import CodecOptions
>>> codec_options = CodecOptions(document_class=RawBSONDocument)
>>> coll = db.get_collection('test', codec_options=codec_options)
>>> doc = coll.find_one()
>>> doc.raw
'\x16\x00\x00\x00\x07_id\x00[0\x165\x91\x10\xea\x14\xe8\xc5\x8b\x93\x00'

The document class can be any type that inherits from MutableMapping:

>>> class AttributeDict(dict):
...     # A dict that supports attribute access.
...     def __getattr__(self, key):
...         return self[key]
...     def __setattr__(self, key, value):
...         self[key] = value
...
>>> codec_options = CodecOptions(document_class=AttributeDict)
>>> coll = db.get_collection('test', codec_options=codec_options)
>>> doc = coll.find_one()
>>> doc._id
ObjectId('5b3016359110ea14e8c58b93')

See Dates and Times for examples using the tz_aware and tzinfo options.

See UUID for examples using the uuid_representation option.

Parameters:

  • document_class (Type[Mapping[str, Any]]) – BSON documents returned in queries will be decoded to an instance of this class. Must be a subclass of MutableMapping. Defaults to dict.

  • tz_aware (bool) – If True, BSON datetimes will be decoded to timezone aware instances of datetime. Otherwise they will be naive. Defaults to False.

  • uuid_representation (int) – The BSON representation to use when encoding and decoding instances of UUID. Defaults to UNSPECIFIED. New applications should consider setting this to STANDARD for cross language compatibility. See UUID representations for details.

  • unicode_decode_error_handler (str) – The error handler to apply when a Unicode-related error occurs during BSON decoding that would otherwise raise UnicodeDecodeError. Valid options include ‘strict’, ‘replace’, ‘backslashreplace’, ‘surrogateescape’, and ‘ignore’. Defaults to ‘strict’.

  • tzinfo (tzinfo | None) – A tzinfo subclass that specifies the timezone to/from which datetime objects should be encoded/decoded.

  • type_registry (TypeRegistry) – Instance of TypeRegistry used to customize encoding and decoding behavior.

  • datetime_conversion (DatetimeConversion | None) – Specifies how UTC datetimes should be decoded within BSON. Valid options include ‘datetime_ms’ to return as a DatetimeMS, ‘datetime’ to return as a datetime.datetime and raising a ValueError for out-of-range values, ‘datetime_auto’ to return DatetimeMS objects when the underlying datetime is out-of-range and ‘datetime_clamp’ to clamp to the minimum and maximum possible datetimes. Defaults to ‘datetime’.

Return type:

CodecOptions

Changed in version 4.0: The default for uuid_representation was changed from PYTHON_LEGACY to UNSPECIFIED.

Added in version 3.8: type_registry attribute.

Warning

Care must be taken when changing unicode_decode_error_handler from its default value (‘strict’). The ‘replace’ and ‘ignore’ modes should not be used when documents retrieved from the server will be modified in the client application and stored back to the server.

with_options(**kwargs)

Make a copy of this CodecOptions, overriding some options:

>>> from bson.codec_options import DEFAULT_CODEC_OPTIONS
>>> DEFAULT_CODEC_OPTIONS.tz_aware
False
>>> options = DEFAULT_CODEC_OPTIONS.with_options(tz_aware=True)
>>> options.tz_aware
True

Added in version 3.5.

Parameters:

kwargs (Any)

Return type:

CodecOptions

class bson.codec_options.DatetimeConversion(*values)

Options for decoding BSON datetimes.

DATETIME = 1

Decode a BSON UTC datetime as a datetime.datetime.

BSON UTC datetimes that cannot be represented as a datetime will raise an OverflowError or a ValueError.

DATETIME_AUTO = 4

Decode a BSON UTC datetime as a datetime.datetime if possible, and a DatetimeMS if not.

DATETIME_CLAMP = 2

Decode a BSON UTC datetime as a datetime.datetime, clamping to min and max.

DATETIME_MS = 3

Decode a BSON UTC datetime as a DatetimeMS object.

class bson.codec_options.TypeCodec

Base class for defining type codec classes which describe how a custom type can be transformed to/from one of the types bson can already encode/decode.

Codec classes must implement the python_type attribute, and the transform_python method to support encoding, as well as the bson_type attribute, and the transform_bson method to support decoding.

See encode data with type codecs documentation for an example.

class bson.codec_options.TypeDecoder

Base class for defining type codec classes which describe how a BSON type can be transformed to a custom type.

Codec classes must implement the bson_type attribute, and the transform_bson method to support decoding.

See encode data with type codecs documentation for an example.

abstract property bson_type: Any

The BSON type to be converted into our own type.

abstractmethod transform_bson(value)

Convert the given BSON value into our own type.

Parameters:

value (Any)

Return type:

Any

class bson.codec_options.TypeEncoder

Base class for defining type codec classes which describe how a custom type can be transformed to one of the types BSON understands.

Codec classes must implement the python_type attribute, and the transform_python method to support encoding.

See encode data with type codecs documentation for an example.

abstract property python_type: Any

The Python type to be converted into something serializable.

abstractmethod transform_python(value)

Convert the given Python object into something serializable.

Parameters:

value (Any)

Return type:

Any

class bson.codec_options.TypeRegistry(type_codecs=None, fallback_encoder=None)

Encapsulates type codecs used in encoding and / or decoding BSON, as well as the fallback encoder. Type registries cannot be modified after instantiation.

TypeRegistry can be initialized with an iterable of type codecs, and a callable for the fallback encoder:

>>> from bson.codec_options import TypeRegistry
>>> type_registry = TypeRegistry([Codec1, Codec2, Codec3, ...],
...                              fallback_encoder)

See add codec to the type registry documentation for an example.

Parameters:

  • type_codecs (Optional[Iterable[_Codec]]) – iterable of type codec instances. If type_codecs contains multiple codecs that transform a single python or BSON type, the transformation specified by the type codec occurring last prevails. A TypeError will be raised if one or more type codecs modify the encoding behavior of a built-in bson type.

  • fallback_encoder (Optional[_Fallback]) – callable that accepts a single, unencodable python value and transforms it into a type that bson can encode. See define a fallback encoder documentation for an example.

property codecs: list[TypeEncoder | TypeDecoder | TypeCodec]

The list of type codecs in this registry.

property fallback_encoder: Callable[[Any], Any] | None

The fallback encoder in this registry.