bson – BSON (Binary JSON) Encoding and Decoding

BSON (Binary JSON) encoding and decoding.

The mapping from Python types to BSON types is as follows:

Python Type	BSON Type	Supported Direction
None	null	both
bool	boolean	both
int [1]	int32 / int64	py -> bson
bson.int64.Int64	int64	both
float	number (real)	both
str	string	both
list	array	both
dict	object	both
SON	object	both
Mapping	object	py -> bson
RawBSONDocument	object	both [2]
datetime.datetime [3] [4]	UTC datetime	both
DatetimeMS	UTC datetime	both [5]
Regex	regex	both
compiled re [7]	regex	py -> bson
Binary	binary	both
uuid.UUID [6]	binary	both
ObjectId	oid	both
DBRef	dbref	both
DBRef	dbpointer	bson -> py
None	undefined	bson -> py
Code	code	both
str	symbol	bson -> py
bytes [8]	binary	both
Timestamp	timestamp	both
Decimal128	decimal128	both
MinKey	min key	both
MaxKey	max key	both

[1]

A Python int will be saved as a BSON int32 or BSON int64 depending on its size. A BSON int32 will always decode to a Python int. A BSON int64 will always decode to a Int64.

[2]

Decoding a bson object to RawBSONDocument can be optionally configured via document_class.

[3]

datetime.datetime instances are encoded with millisecond precision so the microsecond field is truncated.

[4]

all datetime.datetime instances are encoded as UTC. By default, they are decoded as naive but timezone aware datetimes are also supported. See Datetimes and Timezones for examples.

[5]

To enable decoding a bson UTC datetime to a DatetimeMS instance see Handling out of range datetimes.

[6]

For uuid.UUID encoding and decoding behavior see Handling UUID Data.

[7]

Regex instances and regular expression objects from re.compile() are both saved as BSON regular expressions. BSON regular expressions are decoded as Regex instances.

[8]

The bytes type is encoded as BSON binary with subtype 0. It will be decoded back to bytes.

class bson.BSON

BSON (Binary JSON) data.

Warning

Using this class to encode and decode BSON adds a performance cost. For better performance use the module level functions encode() and decode() instead.

decode(codec_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))

Decode this BSON data.

By default, returns a BSON document represented as a Python dict. To use a different MutableMapping class, configure a CodecOptions:

>>> import collections  # From Python standard library.
>>> import bson
>>> from bson.codec_options import CodecOptions
>>> data = bson.BSON.encode({'a': 1})
>>> decoded_doc = bson.BSON(data).decode()
<type 'dict'>
>>> options = CodecOptions(document_class=collections.OrderedDict)
>>> decoded_doc = bson.BSON(data).decode(codec_options=options)
>>> type(decoded_doc)
<class 'collections.OrderedDict'>

Parameters:

codec_options (CodecOptions[Any]) – An instance of CodecOptions.

Return type:

dict[str, Any]

Changed in version 3.0: Removed compile_re option: PyMongo now always represents BSON regular expressions as Regex objects. Use try_compile() to attempt to convert from a BSON regular expression to a Python regular expression object.

Replaced as_class, tz_aware, and uuid_subtype options with codec_options.

classmethod encode(document, check_keys=False, codec_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))

Encode a document to a new BSON instance.

A document can be any mapping type (like dict).

Raises TypeError if document is not a mapping type, or contains keys that are not instances of str'. Raises :class:`~bson.errors.InvalidDocument if document cannot be converted to BSON.

Parameters:

• document (Mapping[str, Any]) – mapping type representing a document

• check_keys (bool) – check if keys start with ‘$’ or contain ‘.’, raising InvalidDocument in either case

• codec_options (CodecOptions[Any]) – An instance of CodecOptions.

Return type:

BSON

Changed in version 3.0: Replaced uuid_subtype option with codec_options.

bson.decode(data: _ReadableBuffer, codec_options: None = None) → dict[str, Any]

bson.decode(data: _ReadableBuffer, codec_options: CodecOptions[_DocumentType]) → _DocumentType

Decode BSON to a document.

By default, returns a BSON document represented as a Python dict. To use a different MutableMapping class, configure a CodecOptions:

>>> import collections  # From Python standard library.
>>> import bson
>>> from bson.codec_options import CodecOptions
>>> data = bson.encode({'a': 1})
>>> decoded_doc = bson.decode(data)
<type 'dict'>
>>> options = CodecOptions(document_class=collections.OrderedDict)
>>> decoded_doc = bson.decode(data, codec_options=options)
>>> type(decoded_doc)
<class 'collections.OrderedDict'>

Parameters:

• data – the BSON to decode. Any bytes-like object that implements the buffer protocol.

• codec_options – An instance of CodecOptions.

Added in version 3.9.

bson.decode_all(data: _ReadableBuffer, codec_options: None = None) → list[dict[str, Any]]

bson.decode_all(data: _ReadableBuffer, codec_options: CodecOptions[_DocumentType]) → list[_DocumentType]

Decode BSON data to multiple documents.

data must be a bytes-like object implementing the buffer protocol that provides concatenated, valid, BSON-encoded documents.

Parameters:

• data – BSON data

• codec_options – An instance of CodecOptions.

Changed in version 3.9: Supports bytes-like objects that implement the buffer protocol.

Changed in version 3.0: Removed compile_re option: PyMongo now always represents BSON regular expressions as Regex objects. Use try_compile() to attempt to convert from a BSON regular expression to a Python regular expression object.

Replaced as_class, tz_aware, and uuid_subtype options with codec_options.

bson.decode_file_iter(file_obj: BinaryIO | IO[bytes], codec_options: None = None) → Iterator[dict[str, Any]]

bson.decode_file_iter(file_obj: BinaryIO | IO[bytes], codec_options: CodecOptions[_DocumentType]) → Iterator[_DocumentType]

Decode bson data from a file to multiple documents as a generator.

Works similarly to the decode_all function, but reads from the file object in chunks and parses bson in chunks, yielding one document at a time.

Parameters:

• file_obj – A file object containing BSON data.

• codec_options – An instance of CodecOptions.

Changed in version 3.0: Replaced as_class, tz_aware, and uuid_subtype options with codec_options.

Added in version 2.8.

bson.decode_iter(data: bytes, codec_options: None = None) → Iterator[dict[str, Any]]

bson.decode_iter(data: bytes, codec_options: CodecOptions[_DocumentType]) → Iterator[_DocumentType]

Decode BSON data to multiple documents as a generator.

Works similarly to the decode_all function, but yields one document at a time.

data must be a string of concatenated, valid, BSON-encoded documents.

Parameters:

• data – BSON data

• codec_options – An instance of CodecOptions.

Changed in version 3.0: Replaced as_class, tz_aware, and uuid_subtype options with codec_options.

Added in version 2.8.

bson.encode(document, check_keys=False, codec_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))

Encode a document to BSON.

A document can be any mapping type (like dict).

Raises TypeError if document is not a mapping type, or contains keys that are not instances of str. Raises InvalidDocument if document cannot be converted to BSON.

Parameters:

• document (Mapping[str, Any]) – mapping type representing a document

• check_keys (bool) – check if keys start with ‘$’ or contain ‘.’, raising InvalidDocument in either case

• codec_options (CodecOptions[Any]) – An instance of CodecOptions.

Return type:

bytes

Added in version 3.9.

bson.gen_list_name()

Generate “keys” for encoded lists in the sequence b”0", b”1", b”2", …

The first 1000 keys are returned from a pre-built cache. All subsequent keys are generated on the fly.

Return type:

Generator[bytes, None, None]

bson.has_c()

Is the C extension installed?

Return type:

bool

bson.is_valid(bson)

Check that the given string represents valid BSON data.

Raises TypeError if bson is not an instance of bytes. Returns True if bson is valid BSON, False otherwise.

Parameters:

bson (bytes) – the data to be validated

Return type:

bool

Sub-modules:

• binary – Tools for representing binary data to be stored in MongoDB
  • BINARY_SUBTYPE
  • FUNCTION_SUBTYPE
  • OLD_BINARY_SUBTYPE
  • OLD_UUID_SUBTYPE
  • UUID_SUBTYPE
  • STANDARD
  • PYTHON_LEGACY
  • JAVA_LEGACY
  • CSHARP_LEGACY
  • MD5_SUBTYPE
  • COLUMN_SUBTYPE
  • SENSITIVE_SUBTYPE
  • USER_DEFINED_SUBTYPE
  • UuidRepresentation
  • BinaryVectorDtype
  • BinaryVector
  • Binary
• code – Tools for representing JavaScript code
  • Code
• codec_options – Tools for specifying BSON codec options
  • CodecOptions
  • DatetimeConversion
  • TypeCodec
  • TypeDecoder
  • TypeEncoder
  • TypeRegistry
• datetime_ms – Support for BSON UTC Datetime
  • DatetimeMS
• dbref – Tools for manipulating DBRefs (references to documents stored in MongoDB)
  • DBRef
• decimal128 – Support for BSON Decimal128
  • Decimal128
  • create_decimal128_context()
• errors – Exceptions raised by the bson package
  • BSONError
  • InvalidBSON
  • InvalidDocument
  • InvalidId
  • InvalidStringData
• int64 – Tools for representing BSON int64
  • Int64
• json_util – Tools for using Python’s json module with BSON documents
  • DatetimeRepresentation
  • JSONMode
  • JSONOptions
  • LEGACY_JSON_OPTIONS
  • CANONICAL_JSON_OPTIONS
  • RELAXED_JSON_OPTIONS
  • DEFAULT_JSON_OPTIONS
  • dumps()
  • loads()
  • object_pairs_hook()
  • object_hook()
  • default()
  • get_size()
• max_key – Representation for the MongoDB internal MaxKey type
  • MaxKey
• min_key – Representation for the MongoDB internal MinKey type
  • MinKey
• objectid – Tools for working with MongoDB ObjectIds
  • ObjectId
• raw_bson – Tools for representing raw BSON documents.
  • Inserting and Retrieving RawBSONDocuments
  • RawBSONDocument
• regex – Tools for representing MongoDB regular expressions
  • Regex
• son – Tools for working with SON, an ordered mapping
  • SON
• timestamp – Tools for representing MongoDB internal Timestamps
  • Timestamp
• tz_util – Utilities for dealing with timezones in Python
  • FixedOffset
  • utc