json_util – Tools for using Python’s json module with BSON documents

Tools for using Python’s json module with BSON documents.

This module provides two helper methods dumps and loads that wrap the native json methods and provide explicit BSON conversion to and from JSON. JSONOptions provides a way to control how JSON is emitted and parsed, with the default being the Relaxed Extended JSON format. json_util can also generate Canonical or legacy Extended JSON when CANONICAL_JSON_OPTIONS or LEGACY_JSON_OPTIONS is provided, respectively.

Example usage (deserialization):

>>> from bson.json_util import loads
>>> loads(
...     '[{"foo": [1, 2]}, {"bar": {"hello": "world"}}, {"code": {"$scope": {}, "$code": "function x() { return 1; }"}}, {"bin": {"$type": "80", "$binary": "AQIDBA=="}}]'
... )
[{'foo': [1, 2]}, {'bar': {'hello': 'world'}}, {'code': Code('function x() { return 1; }', {})}, {'bin': Binary(b'...', 128)}]

Example usage with RELAXED_JSON_OPTIONS (the default):

>>> from bson import Binary, Code
>>> from bson.json_util import dumps
>>> dumps(
...     [
...         {"foo": [1, 2]},
...         {"bar": {"hello": "world"}},
...         {"code": Code("function x() { return 1; }")},
...         {"bin": Binary(b"")},
...     ]
... )
'[{"foo": [1, 2]}, {"bar": {"hello": "world"}}, {"code": {"$code": "function x() { return 1; }"}}, {"bin": {"$binary": {"base64": "AQIDBA==", "subType": "00"}}}]'

Example usage (with CANONICAL_JSON_OPTIONS):

>>> from bson import Binary, Code
>>> from bson.json_util import dumps, CANONICAL_JSON_OPTIONS
>>> dumps(
...     [
...         {"foo": [1, 2]},
...         {"bar": {"hello": "world"}},
...         {"code": Code("function x() { return 1; }")},
...         {"bin": Binary(b"")},
...     ],
...     json_options=CANONICAL_JSON_OPTIONS,
... )
'[{"foo": [{"$numberInt": "1"}, {"$numberInt": "2"}]}, {"bar": {"hello": "world"}}, {"code": {"$code": "function x() { return 1; }"}}, {"bin": {"$binary": {"base64": "AQIDBA==", "subType": "00"}}}]'

Example usage (with LEGACY_JSON_OPTIONS):

>>> from bson import Binary, Code
>>> from bson.json_util import dumps, LEGACY_JSON_OPTIONS
>>> dumps(
...     [
...         {"foo": [1, 2]},
...         {"bar": {"hello": "world"}},
...         {"code": Code("function x() { return 1; }", {})},
...         {"bin": Binary(b"")},
...     ],
...     json_options=LEGACY_JSON_OPTIONS,
... )
'[{"foo": [1, 2]}, {"bar": {"hello": "world"}}, {"code": {"$code": "function x() { return 1; }", "$scope": {}}}, {"bin": {"$binary": "AQIDBA==", "$type": "00"}}]'

Alternatively, you can manually pass the default to json.dumps(). It won’t handle Binary and Code instances (as they are extended strings you can’t provide custom defaults), but it will be faster as there is less recursion.

Note

If your application does not need the flexibility offered by JSONOptions and spends a large amount of time in the json_util module, look to python-bsonjs for a nice performance improvement. python-bsonjs is a fast BSON to MongoDB Extended JSON converter for Python built on top of libbson. python-bsonjs works best with PyMongo when using RawBSONDocument.

class bson.json_util.DatetimeRepresentation
LEGACY = 0

Legacy MongoDB Extended JSON datetime representation.

datetime.datetime instances will be encoded to JSON in the format {“$date”: <dateAsMilliseconds>}, where dateAsMilliseconds is a 64-bit signed integer giving the number of milliseconds since the Unix epoch UTC. This was the default encoding before PyMongo version 3.4.

Added in version 3.4.

NUMBERLONG = 1

NumberLong datetime representation.

datetime.datetime instances will be encoded to JSON in the format {“$date”: {“$numberLong”: “<dateAsMilliseconds>”}}, where dateAsMilliseconds is the string representation of a 64-bit signed integer giving the number of milliseconds since the Unix epoch UTC.

Added in version 3.4.

ISO8601 = 2

ISO-8601 datetime representation.

datetime.datetime instances greater than or equal to the Unix epoch UTC will be encoded to JSON in the format {“$date”: “<ISO-8601>”}. datetime.datetime instances before the Unix epoch UTC will be encoded as if the datetime representation is NUMBERLONG.

Added in version 3.4.

class bson.json_util.JSONMode
LEGACY = 0

Legacy Extended JSON representation.

In this mode, dumps() produces PyMongo’s legacy non-standard JSON output. Consider using RELAXED or CANONICAL instead.

Added in version 3.5.

RELAXED = 1

Relaxed Extended JSON representation.

In this mode, dumps() produces Relaxed Extended JSON, a mostly JSON-like format. Consider using this for things like a web API, where one is sending a document (or a projection of a document) that only uses ordinary JSON type primitives. In particular, the int, Int64, and float numeric types are represented in the native JSON number format. This output is also the most human readable and is useful for debugging and documentation.

See also

The specification for Relaxed Extended JSON.

Added in version 3.5.

CANONICAL = 2

Canonical Extended JSON representation.

In this mode, dumps() produces Canonical Extended JSON, a type preserving format. Consider using this for things like testing, where one has to precisely specify expected types in JSON. In particular, the int, Int64, and float numeric types are encoded with type wrappers.

See also

The specification for Canonical Extended JSON.

Added in version 3.5.

class bson.json_util.JSONOptions(strict_number_long=None, datetime_representation=None, strict_uuid=None, json_mode=1, *args, **kwargs)

Encapsulates JSON options for dumps() and loads().

Parameters:

  • strict_number_long (bool) – If True, Int64 objects are encoded to MongoDB Extended JSON’s Strict mode type NumberLong, ie '{"$numberLong": "<number>" }'. Otherwise they will be encoded as an int. Defaults to False.

  • datetime_representation (int) – The representation to use when encoding instances of datetime.datetime. Defaults to LEGACY.

  • strict_uuid (bool) – If True, uuid.UUID object are encoded to MongoDB Extended JSON’s Strict mode type Binary. Otherwise it will be encoded as '{"$uuid": "<hex>" }'. Defaults to False.

  • json_mode (int) – The JSONMode to use when encoding BSON types to Extended JSON. Defaults to LEGACY.

  • document_class – BSON documents returned by loads() will be decoded to an instance of this class. Must be a subclass of collections.MutableMapping. Defaults to dict.

  • uuid_representation – The UuidRepresentation to use when encoding and decoding instances of uuid.UUID. Defaults to UNSPECIFIED.

  • tz_aware – If True, MongoDB Extended JSON’s Strict mode type Date will be decoded to timezone aware instances of datetime.datetime. Otherwise they will be naive. Defaults to False.

  • tzinfo – A datetime.tzinfo subclass that specifies the timezone from which datetime objects should be decoded. Defaults to utc.

  • datetime_conversion – 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’. See Handling out of range datetimes for details.

  • args (Any) – arguments to CodecOptions

  • kwargs (Any) – arguments to CodecOptions

Return type:

JSONOptions

See also

The specification for Relaxed and Canonical Extended JSON.

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

Changed in version 3.5: Accepts the optional parameter json_mode.

Changed in version 4.0: Changed default value of tz_aware to False.

json_mode: int
strict_number_long: bool
datetime_representation: int
strict_uuid: bool
with_options(**kwargs)

Make a copy of this JSONOptions, overriding some options:

>>> from bson.json_util import CANONICAL_JSON_OPTIONS
>>> CANONICAL_JSON_OPTIONS.tz_aware
True
>>> json_options = CANONICAL_JSON_OPTIONS.with_options(tz_aware=False, tzinfo=None)
>>> json_options.tz_aware
False

Added in version 3.12.

Parameters:

kwargs (Any)

Return type:

JSONOptions

bson.json_util.LEGACY_JSON_OPTIONS: JSONOptions = (<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME)

JSONOptions for encoding to PyMongo’s legacy JSON format.

See also

The documentation for bson.json_util.JSONMode.LEGACY.

Added in version 3.5.

bson.json_util.CANONICAL_JSON_OPTIONS: JSONOptions = (<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME)

JSONOptions for Canonical Extended JSON.

See also

The documentation for bson.json_util.JSONMode.CANONICAL.

Added in version 3.5.

bson.json_util.RELAXED_JSON_OPTIONS: JSONOptions = (<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME)

JSONOptions for Relaxed Extended JSON.

See also

The documentation for bson.json_util.JSONMode.RELAXED.

Added in version 3.5.

bson.json_util.DEFAULT_JSON_OPTIONS: JSONOptions = (<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME)

The default JSONOptions for JSON encoding/decoding.

The same as RELAXED_JSON_OPTIONS.

Changed in version 4.0: Changed from LEGACY_JSON_OPTIONS to RELAXED_JSON_OPTIONS.

Added in version 3.4.

bson.json_util.dumps(obj, *args, **kwargs)

Helper function that wraps json.dumps().

Recursive function that handles all BSON types including Binary and Code.

Parameters:
Return type:

str

Changed in version 4.0: Now outputs MongoDB Relaxed Extended JSON by default (using DEFAULT_JSON_OPTIONS).

Changed in version 3.4: Accepts optional parameter json_options. See JSONOptions.

bson.json_util.loads(s, *args, **kwargs)

Helper function that wraps json.loads().

Automatically passes the object_hook for BSON type conversion.

Raises TypeError, ValueError, KeyError, or InvalidId on invalid MongoDB Extended JSON.

Parameters:
Return type:

Any

Changed in version 4.0: Now loads datetime.datetime instances as naive by default. To load timezone aware instances utilize the json_options parameter. See tz_aware defaults to False for an example.

Changed in version 3.5: Parses Relaxed and Canonical Extended JSON as well as PyMongo’s legacy format. Now raises TypeError or ValueError when parsing JSON type wrappers with values of the wrong type or any extra keys.

Changed in version 3.4: Accepts optional parameter json_options. See JSONOptions.

bson.json_util.object_pairs_hook(pairs, json_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))
Parameters:
Return type:

Any

bson.json_util.object_hook(dct, json_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))
Parameters:
Return type:

Any

bson.json_util.default(obj, json_options=(<class 'dict'>, False, 0, 'strict', None, TypeRegistry(type_codecs=[], fallback_encoder=None), DatetimeConversion.DATETIME))
Parameters:
Return type:

Any

bson.json_util.get_size(obj, max_size, current_size=0)

Recursively finds size of objects

Parameters:

  • obj (Any)

  • max_size (int)

  • current_size (int)

Return type:

int