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DOCSP-46694 - Extended JSON (#169) (#174)
Co-authored-by: Jordan Smith <[email protected]> (cherry picked from commit fe2c41a) Co-authored-by: Mike Woofter <[email protected]>
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‎source/data-formats.txt

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:maxdepth: 1
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BSON </data-formats/bson>
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Extended JSON </data-formats/extended-json>
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Custom Types </data-formats/custom-types>
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Dates & Times </data-formats/dates-and-times>
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UUIDs </data-formats/uuid>
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sections:
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- Learn how to work with BSON documents in the :ref:`pymongo-bson` guide.
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- Learn how to translate BSON to Extended JSON in the :ref:`pymongo-extended-json` guide.
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- Learn how to encode and decode custom types in the :ref:`pymongo-custom-types` guide.
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- Learn how to work with Python ``datetime`` objects in {+driver-short+} in the
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:ref:`pymongo-dates-times` guide.

‎source/data-formats/extended-json.txt

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.. _pymongo-extended-json:
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=============
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Extended JSON
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=============
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.. contents:: On this page
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:local:
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:backlinks: none
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:depth: 2
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:class: singlecol
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.. facet::
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:name: genre
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:values: reference
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.. meta::
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:keywords: code examples, bson, relaxed, canonical, legacy
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Overview
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--------
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JSON is a data format that represents the values of objects, arrays, numbers,
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strings, booleans, and nulls. The **Extended JSON** format defines a reserved
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set of keys prefixed with "``$``" to represent field type information that
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directly corresponds to each type in BSON, the format that MongoDB uses to
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store data.
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Extended JSON Formats
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---------------------
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MongoDB Extended JSON features different string formats to represent BSON data.
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Each of the different formats conform to the JSON RFC
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and meet specific use cases. The **extended** format, also known as the
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**canonical** format, features specific representations for every BSON type
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for bidirectional conversion without loss of information. The **Relaxed mode**
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format is more concise and closer to ordinary JSON, but does not represent
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all the type information such as the specific byte size of number fields.
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See the following table to see a description of each format:
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.. list-table::
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:header-rows: 1
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:stub-columns: 1
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:widths: 10 40
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* - Name
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- Description
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* - **Extended**
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- | Also known as the *canonical* format, this JSON representation avoids loss of
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BSON type information.
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| This format prioritizes type preservation at the loss of human-readability and
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interoperability with older formats.
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* - **Relaxed Mode**
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- | JSON representation that describes BSON documents with some type information loss.
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| This format prioritizes human-readability and interoperability at the loss of
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certain type information.
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* - **Shell**
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- | JSON representation that matches the syntax used in the MongoDB shell.
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| This format prioritizes compatibility with the MongoDB shell, which often uses
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JavaScript functions to represent types.
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* - **Strict**
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- | *Deprecated.* This representation is the legacy format that fully conforms to
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the `JSON RFC <http://www.json.org/>`__ which allows any JSON parser to read the type information.
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.. _extended_json_example_section:
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.. note::
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The driver parses the ``$uuid`` Extended JSON type from a string to a
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``BsonBinary`` object of binary subtype 4. For more information about ``$uuid`` field
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parsing, see the
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:spec:`special rules for parsing $uuid fields </extended-json.rst#special-rules-for-parsing-uuid-fields>`
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section in the extended JSON specification.
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To learn more about JSON, BSON, and Extended JSON, see
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`our article about JSON and BSON <https://www.mongodb.com/resources/basics/json-and-bson>`__
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and :manual:`Extended JSON </reference/mongodb-extended-json/>` in the {+mdb-server+} manual.
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Extended JSON Examples
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~~~~~~~~~~~~~~~~~~~~~~
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The following examples show a document containing an ObjectId, date, and long
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number field represented in each Extended JSON format. Click the tab that
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corresponds to the format of the example you want to see:
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.. tabs::
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.. tab:: Extended
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:tabid: extended-format
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.. code-block:: json
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{
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"_id": { "$oid": "573a1391f29313caabcd9637" },
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"createdAt": { "$date": { "$numberLong": "1601499609" }},
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"numViews": { "$numberLong": "36520312" }
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}
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.. tab:: Relaxed Mode
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:tabid: relaxed-mode-format
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.. code-block:: json
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{
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"_id": { "$oid": "573a1391f29313caabcd9637" },
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"createdAt": { "$date": "2020-09-30T18:22:51.648Z" },
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"numViews": 36520312
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}
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.. tab:: Shell
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:tabid: shell-format
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.. code-block:: json
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{
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"_id": ObjectId("573a1391f29313caabcd9637"),
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"createdAt": ISODate("2020-09-30T18:22:51.648Z"),
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"numViews": NumberLong("36520312")
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}
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.. tab:: Strict
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:tabid: strict-format
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.. code-block:: json
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{
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"_id": { "$oid": "573a1391f29313caabcd9637" },
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"createdAt": { "$date": 1601499609 },
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"numViews": { "$numberLong": "36520312" }
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}
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Read Extended JSON
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------------------
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You can read an Extended JSON string into a Python object by calling
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the ``bson.json_util.loads()`` method. This method parses an Extended
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JSON string and returns a Python list containing the data.
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The following example shows how you can read an Extended JSON string into a
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list of dictionaries by using the ``loads()`` method:
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.. io-code-block::
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.. input::
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:language: python
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from bson.json_util import loads
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ejson_str = '''[
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{"foo": [1, 2]},
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{"bar": {"hello": "world"}},
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{"code": {
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"$scope": {},
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"$code": "function x() { return 1; }"
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}},
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{"bin": {
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"$type": "80",
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"$binary": "AQIDBA=="
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}}
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]'''
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doc = loads(ejson_str)
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print(doc)
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.. output::
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:language: none
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:visible: false
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[
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{'foo': [1, 2]},
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{'bar': {'hello': 'world'}},
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{'code': Code('function x() { return 1; }', {})},
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{'bin': Binary(b'\x01\x02\x03\x04', 128)}
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]
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Write Extended JSON
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-------------------
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You can write an Extended JSON string from a list of dictionaries
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by calling the ``bson.json_util.dumps()`` method.
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The following example outputs an Extended JSON string in the Relaxed format:
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.. io-code-block::
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.. input::
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:language: python
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from bson import Code, Binary
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from bson.json_util import dumps
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doc = [
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{'foo': [1, 2]},
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{'bar': {'hello': 'world'}},
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{'code': Code('function x() { return 1; }', {})},
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{'bin': Binary(b'\x01\x02\x03\x04', 128)}
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]
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ejson_str = dumps(doc)
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print(ejson_str)
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.. output::
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:language: none
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:visible: false
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'''[
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{"foo": [1, 2]},
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{"bar": {"hello": "world"}},
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{"code": {
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"$code": "function x() { return 1; }",
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"$scope": {}
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}},
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{"bin": {
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"$binary": {
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"base64": "AQIDBA==",
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"subType": "80"
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}}}
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]'''
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By default, the ``dumps()`` method returns the Extended JSON string in the Relaxed
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format. To specify a different format, pass one of the following values for the
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``json_options`` parameter:
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- ``CANONICAL_JSON_OPTIONS``: Returns the Extended JSON string in Canonical format.
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- ``LEGACY_JSON_OPTIONS``: Returns the Extended JSON string in Legacy format.
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We recommend using Relaxed or Canonical format instead.
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The following example shows how to output Extended JSON in the Canonical format:
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.. io-code-block::
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.. input::
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:language: python
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from bson import Code, Binary
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from bson.json_util import dumps, CANONICAL_JSON_OPTIONS
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doc = [
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{'foo': [1, 2]},
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{'bar': {'hello': 'world'}},
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{'code': Code('function x() { return 1; }', {})},
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{'bin': Binary(b'\x01\x02\x03\x04', 128)}
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]
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ejson_str = dumps(doc, json_options=CANONICAL_JSON_OPTIONS)
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print(ejson_str)
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.. output::
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:language: none
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:visible: false
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'''[
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{"foo": [
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{"$numberInt": "1"},
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{"$numberInt": "2"}
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]},
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{"bar": {"hello": "world"}},
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{"code": {
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"$code": "function x() { return 1; }",
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"$scope": {}
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}},
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{"bin": {
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"$binary": {
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"base64": "AQIDBA==",
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"subType": "80"
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}}}
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]'''
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Additional Information
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----------------------
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For more information about the methods and types in ``bson.json_util``, see the following
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API documentation:
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- `loads() <{+api-root+}bson/json_util.html#bson.json_util.loads>`__
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- `dumps() <{+api-root+}bson/json_util.html#bson.json_util.dumps>`__
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- `CANONICAL_JSON_OPTIONS <{+api-root+}bson/json_util.html#bson.json_util.CANONICAL_JSON_OPTIONS>`__
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- `LEGACY_JSON_OPTIONS <{+api-root+}bson/json_util.html#bson.json_util.LEGACY_JSON_OPTIONS>`__

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