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# Copyright 2013 Rackspace, Inc.
#
# 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.
import json
import uuid
class Serializable(object):
"""Base class for things that can be serialized."""
serializable_fields = ()
def serialize(self):
"""Turn this object into a dict."""
return dict((f, getattr(self, f)) for f in self.serializable_fields)
class SerializableComparable(Serializable):
"""A Serializable class which supports some comparison operators
This class supports the '__eq__' and '__ne__' comparison operators, but
intentionally disables the '__hash__' operator as some child classes may be
mutable. The addition of these comparison operators is mainly used to
assist with unit testing.
"""
__hash__ = None
def __eq__(self, other):
return self.serialize() == other.serialize()
def __ne__(self, other):
return self.serialize() != other.serialize()
class RESTJSONEncoder(json.JSONEncoder):
"""A slightly customized JSON encoder."""
def encode(self, o):
"""Turn an object into JSON.
Appends a newline to responses when configured to pretty-print,
in order to make use of curl less painful from most shells.
"""
delimiter = ''
# if indent is None, newlines are still inserted, so we should too.
if self.indent is not None:
delimiter = '\n'
return super(RESTJSONEncoder, self).encode(o) + delimiter
def default(self, o):
"""Turn an object into a serializable object.
In particular, by calling :meth:`.Serializable.serialize` on `o`.
"""
if isinstance(o, Serializable):
return o.serialize()
elif isinstance(o, uuid.UUID):
return str(o)
else:
return json.JSONEncoder.default(self, o)
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