codec_options – Tools for specifying BSON codec options

Tools for specifying BSON codec options.

class bson.codec_options.CodecOptions

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 Datetimes and Timezones for examples using the tz_aware and tzinfo options.

See UUIDLegacy for examples using the uuid_representation option.

Parameters:
  • document_class: 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: If True, BSON datetimes will be decoded to timezone aware instances of datetime. Otherwise they will be naive. Defaults to False.
  • uuid_representation: The BSON representation to use when encoding and decoding instances of UUID. Defaults to PYTHON_LEGACY.
  • unicode_decode_error_handler: The error handler to apply when a Unicode-related error occurs during BSON decoding that would otherwise raise UnicodeDecodeError. Valid options include ‘strict’, ‘replace’, and ‘ignore’. Defaults to ‘strict’.
  • tzinfo: A tzinfo subclass that specifies the timezone to/from which datetime objects should be encoded/decoded.
  • type_registry: Instance of TypeRegistry used to customize encoding and decoding behavior.

New 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

New in version 3.5.

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 The TypeCodec Class 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 The TypeCodec Class documentation for an example.

bson_type

The BSON type to be converted into our own type.

transform_bson(value)

Convert the given BSON value into our own type.

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 The TypeCodec Class documentation for an example.

python_type

The Python type to be converted into something serializable.

transform_python(value)

Convert the given Python object into something serializable.

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 The TypeRegistry Class documentation for an example.

Parameters:
  • type_codecs (optional): 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): callable that accepts a single, unencodable python value and transforms it into a type that bson can encode. See The fallback_encoder Callable documentation for an example.