275 lines
11 KiB
Python
275 lines
11 KiB
Python
# Copyright 2014-present MongoDB, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Tools for specifying BSON codec options."""
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import datetime
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from collections import namedtuple
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from bson.py3compat import abc, string_type
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from bson.binary import (ALL_UUID_REPRESENTATIONS,
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PYTHON_LEGACY,
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UUID_REPRESENTATION_NAMES)
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_RAW_BSON_DOCUMENT_MARKER = 101
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def _raw_document_class(document_class):
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"""Determine if a document_class is a RawBSONDocument class."""
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marker = getattr(document_class, '_type_marker', None)
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return marker == _RAW_BSON_DOCUMENT_MARKER
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class TypeCodecBase(object):
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"""Base class for defining type codec classes which describe how a
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custom type can be transformed to/from one of the types BSON already
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understands, and can encode/decode.
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Codec classes must implement the ``python_type`` property, and the
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``transform_python`` method to support encoding, or the ``bson_type``
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property and ``transform_bson`` method to support decoding. Note that a
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single codec class may support both encoding and decoding.
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"""
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@property
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def python_type(self):
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"""The Python type to be converted into something serializable."""
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raise NotImplementedError
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@property
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def bson_type(self):
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"""The BSON type to be converted into our own type."""
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raise NotImplementedError
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def transform_bson(self, value):
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"""Convert the given BSON value into our own type."""
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raise NotImplementedError
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def transform_python(self, value):
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"""Convert the given Python object into something serializable."""
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raise NotImplementedError
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class TypeRegistry(object):
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"""Encapsulates type codecs used in encoding and / or decoding BSON.
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``TypeRegistry`` can be initialized with an arbitrary number of type
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codecs::
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>>> from bson.codec_options import TypeRegistry
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>>> type_registry = TypeRegistry(Codec1, Codec2, Codec3, ...)
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If multiple codecs try to transform a single python or BSON type,
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the transformation described by the last type codec prevails.
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"""
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def __init__(self, *type_codecs):
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self.__args = type_codecs
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self._encoder_map = {}
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self._decoder_map = {}
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for codec in type_codecs:
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if not isinstance(codec, TypeCodecBase):
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raise TypeError(
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"Expected an instance of %s, got %r instead" % (
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TypeCodecBase.__name__, codec))
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try:
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python_type = codec.python_type
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except NotImplementedError:
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pass
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else:
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self._encoder_map[python_type] = codec.transform_python
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try:
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bson_type = codec.bson_type
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except NotImplementedError:
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pass
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else:
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self._decoder_map[bson_type] = codec.transform_bson
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def __repr__(self):
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return '%s%r' % (self.__class__.__name__, self.__args)
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def __eq__(self, other):
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if not isinstance(other, type(self)):
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return NotImplemented
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return ((self._decoder_map == other._decoder_map) and
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(self._encoder_map == other._encoder_map))
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_options_base = namedtuple(
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'CodecOptions',
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('document_class', 'tz_aware', 'uuid_representation',
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'unicode_decode_error_handler', 'tzinfo', 'type_registry'))
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class CodecOptions(_options_base):
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"""Encapsulates options used encoding and / or decoding BSON.
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The `document_class` option is used to define a custom type for use
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decoding BSON documents. Access to the underlying raw BSON bytes for
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a document is available using the :class:`~bson.raw_bson.RawBSONDocument`
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type::
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>>> from bson.raw_bson import RawBSONDocument
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>>> from bson.codec_options import CodecOptions
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>>> codec_options = CodecOptions(document_class=RawBSONDocument)
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>>> coll = db.get_collection('test', codec_options=codec_options)
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>>> doc = coll.find_one()
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>>> doc.raw
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'\\x16\\x00\\x00\\x00\\x07_id\\x00[0\\x165\\x91\\x10\\xea\\x14\\xe8\\xc5\\x8b\\x93\\x00'
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The document class can be any type that inherits from
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:class:`~collections.MutableMapping`::
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>>> class AttributeDict(dict):
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... # A dict that supports attribute access.
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... def __getattr__(self, key):
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... return self[key]
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... def __setattr__(self, key, value):
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... self[key] = value
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...
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>>> codec_options = CodecOptions(document_class=AttributeDict)
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>>> coll = db.get_collection('test', codec_options=codec_options)
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>>> doc = coll.find_one()
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>>> doc._id
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ObjectId('5b3016359110ea14e8c58b93')
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See :doc:`/examples/datetimes` for examples using the `tz_aware` and
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`tzinfo` options.
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See :class:`~bson.binary.UUIDLegacy` for examples using the
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`uuid_representation` option.
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:Parameters:
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- `document_class`: BSON documents returned in queries will be decoded
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to an instance of this class. Must be a subclass of
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:class:`~collections.MutableMapping`. Defaults to :class:`dict`.
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- `tz_aware`: If ``True``, BSON datetimes will be decoded to timezone
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aware instances of :class:`~datetime.datetime`. Otherwise they will be
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naive. Defaults to ``False``.
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- `uuid_representation`: The BSON representation to use when encoding
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and decoding instances of :class:`~uuid.UUID`. Defaults to
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:data:`~bson.binary.PYTHON_LEGACY`.
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- `unicode_decode_error_handler`: The error handler to apply when
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a Unicode-related error occurs during BSON decoding that would
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otherwise raise :exc:`UnicodeDecodeError`. Valid options include
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'strict', 'replace', and 'ignore'. Defaults to 'strict'.
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- `tzinfo`: A :class:`~datetime.tzinfo` subclass that specifies the
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timezone to/from which :class:`~datetime.datetime` objects should be
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encoded/decoded.
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- `type_registry`: Instance of :class:`TypeRegistry` used to customize
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encoding and decoding behavior.
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.. warning:: Care must be taken when changing
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`unicode_decode_error_handler` from its default value ('strict').
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The 'replace' and 'ignore' modes should not be used when documents
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retrieved from the server will be modified in the client application
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and stored back to the server.
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"""
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def __new__(cls, document_class=dict,
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tz_aware=False, uuid_representation=PYTHON_LEGACY,
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unicode_decode_error_handler="strict",
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tzinfo=None, type_registry=None):
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if not (issubclass(document_class, abc.MutableMapping) or
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_raw_document_class(document_class)):
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raise TypeError("document_class must be dict, bson.son.SON, "
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"bson.raw_bson.RawBSONDocument, or a "
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"sublass of collections.MutableMapping")
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if not isinstance(tz_aware, bool):
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raise TypeError("tz_aware must be True or False")
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if uuid_representation not in ALL_UUID_REPRESENTATIONS:
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raise ValueError("uuid_representation must be a value "
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"from bson.binary.ALL_UUID_REPRESENTATIONS")
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if not isinstance(unicode_decode_error_handler, (string_type, None)):
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raise ValueError("unicode_decode_error_handler must be a string "
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"or None")
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if tzinfo is not None:
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if not isinstance(tzinfo, datetime.tzinfo):
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raise TypeError(
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"tzinfo must be an instance of datetime.tzinfo")
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if not tz_aware:
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raise ValueError(
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"cannot specify tzinfo without also setting tz_aware=True")
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type_registry = type_registry or TypeRegistry()
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if not isinstance(type_registry, TypeRegistry):
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raise TypeError("type_registry must be an instance of TypeRegistry")
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return tuple.__new__(
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cls, (document_class, tz_aware, uuid_representation,
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unicode_decode_error_handler, tzinfo, type_registry))
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def _arguments_repr(self):
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"""Representation of the arguments used to create this object."""
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document_class_repr = (
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'dict' if self.document_class is dict
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else repr(self.document_class))
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uuid_rep_repr = UUID_REPRESENTATION_NAMES.get(self.uuid_representation,
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self.uuid_representation)
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return ('document_class=%s, tz_aware=%r, uuid_representation=%s, '
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'unicode_decode_error_handler=%r, tzinfo=%r, '
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'type_registry=%r' %
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(document_class_repr, self.tz_aware, uuid_rep_repr,
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self.unicode_decode_error_handler, self.tzinfo,
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self.type_registry))
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def __repr__(self):
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return '%s(%s)' % (self.__class__.__name__, self._arguments_repr())
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def with_options(self, **kwargs):
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"""Make a copy of this CodecOptions, overriding some options::
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>>> from bson.codec_options import DEFAULT_CODEC_OPTIONS
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>>> DEFAULT_CODEC_OPTIONS.tz_aware
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False
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>>> options = DEFAULT_CODEC_OPTIONS.with_options(tz_aware=True)
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>>> options.tz_aware
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True
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.. versionadded:: 3.5
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"""
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return CodecOptions(
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kwargs.get('document_class', self.document_class),
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kwargs.get('tz_aware', self.tz_aware),
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kwargs.get('uuid_representation', self.uuid_representation),
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kwargs.get('unicode_decode_error_handler',
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self.unicode_decode_error_handler),
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kwargs.get('tzinfo', self.tzinfo),
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kwargs.get('type_registry', self.type_registry)
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)
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DEFAULT_CODEC_OPTIONS = CodecOptions()
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def _parse_codec_options(options):
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"""Parse BSON codec options."""
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return CodecOptions(
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document_class=options.get(
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'document_class', DEFAULT_CODEC_OPTIONS.document_class),
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tz_aware=options.get(
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'tz_aware', DEFAULT_CODEC_OPTIONS.tz_aware),
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uuid_representation=options.get(
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'uuidrepresentation', DEFAULT_CODEC_OPTIONS.uuid_representation),
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unicode_decode_error_handler=options.get(
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'unicode_decode_error_handler',
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DEFAULT_CODEC_OPTIONS.unicode_decode_error_handler),
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tzinfo=options.get('tzinfo', DEFAULT_CODEC_OPTIONS.tzinfo),
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type_registry=options.get(
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'type_registry', DEFAULT_CODEC_OPTIONS.type_registry))
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