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R3600/invenio/utils/serializers.py
31e9162ba344iugw2017

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serializers.py
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# -*- coding: utf-8 -*-
# This file is part of Invenio.
# Copyright (C) 2013, 2015 CERN.
#
# Invenio is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# Invenio is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Invenio; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""Implements custom serializers."""
import marshal
import zlib
from backports import lzma
from six.moves import cPickle as pickle
__all__ = ['ZlibMarshal',
'ZlibPickle',
'LzmaPickle',
'SerializerError',
'serialize_via_marshal',
'deserialize_via_marshal',
'serialize_via_pickle',
'deserialize_via_pickle']
class SerializerError(Exception):
"""Error during (de-)serialization."""
pass
class ZlibMarshal(object):
"""Combines zlib and marshal libraries."""
@staticmethod
def loads(astring):
"""Decompress and deserialize string into Python object via marshal."""
try:
return marshal.loads(zlib.decompress(astring))
except zlib.error as e:
raise SerializerError(
'Cannot decompress object ("{}")'.format(str(e))
)
except Exception as e:
# marshal module does not provide a proper Exception model
raise SerializerError(
'Cannot restore object ("{}")'.format(str(e))
)
@staticmethod
def dumps(obj):
"""Serialize Python object via marshal into ompressed string."""
return zlib.compress(marshal.dumps(obj))
# Provides legacy API functions.
serialize_via_marshal = ZlibMarshal.dumps
deserialize_via_marshal = ZlibMarshal.loads
class ZlibPickle(object):
"""Combines zlib and pickle libraries."""
@staticmethod
def loads(astring):
"""Decompress and deserialize string into Python object via pickle."""
try:
return pickle.loads(zlib.decompress(astring))
except zlib.error as e:
raise SerializerError(
'Cannot decompress object ("{}")'.format(str(e))
)
except pickle.UnpicklingError as e:
raise SerializerError(
'Cannot restore object ("{}")'.format(str(e))
)
@staticmethod
def dumps(obj):
"""Serialize Python object via pickle into compressed string."""
return zlib.compress(pickle.dumps(obj))
# Provides legacy API functions.
serialize_via_pickle = ZlibPickle.dumps
deserialize_via_pickle = ZlibPickle.loads
class LzmaPickle(object):
"""Combines lzma and pickle libraries."""
@staticmethod
def loads(astring):
"""Decompress and deserialize string into a Python object via pickle."""
try:
return pickle.loads(lzma.decompress(astring))
except lzma.LZMAError as e:
raise SerializerError(
'Cannot decompress object ("{}")'.format(str(e))
)
except pickle.UnpicklingError as e:
raise SerializerError(
'Cannot restore object ("{}")'.format(str(e))
)
@staticmethod
def dumps(obj):
"""Serialize Python object via pickle into a compressed string."""
return lzma.compress(pickle.dumps(obj))
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