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oslo.serialization
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oslo.serialization/oslo_serialization/jsonutils.py

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# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Justin Santa Barbara
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
'''
JSON related utilities.
This module provides a few things:
#. A handy function for getting an object down to something that can be
JSON serialized. See :func:`.to_primitive`.
#. Wrappers around :func:`.loads` and :func:`.dumps`. The :func:`.dumps`
wrapper will automatically use :func:`.to_primitive` for you if needed.
#. This sets up ``anyjson`` to use the :func:`.loads` and :func:`.dumps`
wrappers if ``anyjson`` is available.
'''
import codecs
import datetime
import functools
import inspect
import itertools
import sys
import uuid
is_simplejson = False
if sys.version_info < (2, 7):
# On Python <= 2.6, json module is not C boosted, so try to use
# simplejson module if available
try:
import simplejson as json
# NOTE(mriedem): Make sure we have a new enough version of simplejson
# to support the namedobject_as_tuple argument. This can be removed
# in the Kilo release when python 2.6 support is dropped.
if 'namedtuple_as_object' in inspect.getargspec(json.dumps).args:
is_simplejson = True
else:
import json
except ImportError:
import json
else:
import json
from oslo_utils import encodeutils
from oslo_utils import importutils
from oslo_utils import timeutils
import six
import six.moves.xmlrpc_client as xmlrpclib
netaddr = importutils.try_import("netaddr")
_nasty_type_tests = [inspect.ismodule, inspect.isclass, inspect.ismethod,
inspect.isfunction, inspect.isgeneratorfunction,
inspect.isgenerator, inspect.istraceback, inspect.isframe,
inspect.iscode, inspect.isbuiltin, inspect.isroutine,
inspect.isabstract]
_simple_types = (six.string_types + six.integer_types
+ (type(None), bool, float))
def to_primitive(value, convert_instances=False, convert_datetime=True,
level=0, max_depth=3):
"""Convert a complex object into primitives.
Handy for JSON serialization. We can optionally handle instances,
but since this is a recursive function, we could have cyclical
data structures.
To handle cyclical data structures we could track the actual objects
visited in a set, but not all objects are hashable. Instead we just
track the depth of the object inspections and don't go too deep.
Therefore, ``convert_instances=True`` is lossy ... be aware.
"""
# handle obvious types first - order of basic types determined by running
# full tests on nova project, resulting in the following counts:
# 572754 <type 'NoneType'>
# 460353 <type 'int'>
# 379632 <type 'unicode'>
# 274610 <type 'str'>
# 199918 <type 'dict'>
# 114200 <type 'datetime.datetime'>
# 51817 <type 'bool'>
# 26164 <type 'list'>
# 6491 <type 'float'>
# 283 <type 'tuple'>
# 19 <type 'long'>
if isinstance(value, _simple_types):
return value
# It's not clear why xmlrpclib created their own DateTime type, but
# for our purposes, make it a datetime type which is explicitly
# handled
if isinstance(value, xmlrpclib.DateTime):
value = datetime.datetime(*tuple(value.timetuple())[:6])
if isinstance(value, datetime.datetime):
if convert_datetime:
return value.strftime(timeutils.PERFECT_TIME_FORMAT)
else:
return value
if isinstance(value, uuid.UUID):
return six.text_type(value)
if netaddr and isinstance(value, netaddr.IPAddress):
return six.text_type(value)
# value of itertools.count doesn't get caught by nasty_type_tests
# and results in infinite loop when list(value) is called.
if type(value) == itertools.count:
return six.text_type(value)
if any(test(value) for test in _nasty_type_tests):
return six.text_type(value)
# FIXME(vish): Workaround for LP bug 852095. Without this workaround,
# tests that raise an exception in a mocked method that
# has a @wrap_exception with a notifier will fail. If
# we up the dependency to 0.5.4 (when it is released) we
# can remove this workaround.
if getattr(value, '__module__', None) == 'mox':
return 'mock'
if level > max_depth:
return '?'
# The try block may not be necessary after the class check above,
# but just in case ...
try:
recursive = functools.partial(to_primitive,
convert_instances=convert_instances,
convert_datetime=convert_datetime,
level=level,
max_depth=max_depth)
if isinstance(value, dict):
return dict((recursive(k), recursive(v))
for k, v in six.iteritems(value))
elif hasattr(value, 'iteritems'):
return recursive(dict(value.iteritems()), level=level + 1)
elif hasattr(value, '__iter__'):
return list(map(recursive, value))
elif convert_instances and hasattr(value, '__dict__'):
# Likely an instance of something. Watch for cycles.
# Ignore class member vars.
return recursive(value.__dict__, level=level + 1)
except TypeError:
# Class objects are tricky since they may define something like
# __iter__ defined but it isn't callable as list().
return six.text_type(value)
return value
JSONEncoder = json.JSONEncoder
JSONDecoder = json.JSONDecoder
def dumps(obj, default=to_primitive, **kwargs):
"""Serialize ``obj`` to a JSON formatted ``str``.
:param obj: object to be serialized
:param default: function that returns a serializable version of an object
:param kwargs: extra named parameters, please see documentation \
of `json.dumps <https://docs.python.org/2/library/json.html#basic-usage>`_
:returns: json formatted string
"""
if is_simplejson:
kwargs['namedtuple_as_object'] = False
return json.dumps(obj, default=default, **kwargs)
def dump(obj, fp, *args, **kwargs):
"""Serialize ``obj`` as a JSON formatted stream to ``fp``
:param obj: object to be serialized
:param fp: a ``.write()``-supporting file-like object
:param default: function that returns a serializable version of an object
:param args: extra arguments, please see documentation \
of `json.dump <https://docs.python.org/2/library/json.html#basic-usage>`_
:param kwargs: extra named parameters, please see documentation \
of `json.dump <https://docs.python.org/2/library/json.html#basic-usage>`_
"""
default = kwargs.get('default', to_primitive)
if is_simplejson:
kwargs['namedtuple_as_object'] = False
return json.dump(obj, fp, default=default, *args, **kwargs)
def loads(s, encoding='utf-8', **kwargs):
"""Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON
:param s: string to deserialize
:param encoding: encoding used to interpret the string
:param kwargs: extra named parameters, please see documentation \
of `json.loads <https://docs.python.org/2/library/json.html#basic-usage>`_
:returns: python object
"""
return json.loads(encodeutils.safe_decode(s, encoding), **kwargs)
def load(fp, encoding='utf-8', **kwargs):
"""Deserialize ``fp`` to a Python object.
:param fp: a ``.read()`` -supporting file-like object
:param encoding: encoding used to interpret the string
:param kwargs: extra named parameters, please see documentation \
of `json.loads <https://docs.python.org/2/library/json.html#basic-usage>`_
:returns: python object
"""
return json.load(codecs.getreader(encoding)(fp), **kwargs)
try:
import anyjson
except ImportError:
pass
else:
anyjson._modules.append((__name__, 'dumps', TypeError,
'loads', ValueError, 'load'))
anyjson.force_implementation(__name__)
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