# -*- coding: utf-8 -*-
"""The json serializer object implementation."""
from __future__ import unicode_literals
import binascii
import codecs
import collections
import json
from dfvfs.path import path_spec as dfvfs_path_spec
from dfvfs.path import factory as dfvfs_path_spec_factory
from plaso.containers import interface as containers_interface
from plaso.containers import manager as containers_manager
from plaso.lib import py2to3
from plaso.serializer import interface
from plaso.serializer import logger
[docs]class JSONAttributeContainerSerializer(interface.AttributeContainerSerializer):
"""Class that implements the json attribute container serializer."""
@classmethod
def _ConvertAttributeContainerToDict(cls, attribute_container):
"""Converts an attribute container object into a JSON dictionary.
The resulting dictionary of the JSON serialized objects consists of:
{
'__type__': 'AttributeContainer'
'__container_type__': ...
...
}
Here '__type__' indicates the object base type. In this case
'AttributeContainer'.
'__container_type__' indicates the container type and rest of the elements
of the dictionary make up the attributes of the container.
Args:
attribute_container (AttributeContainer): attribute container.
Returns:
dict[str, object]: JSON serialized objects.
Raises:
TypeError: if not an instance of AttributeContainer.
ValueError: if the attribute container type is not supported.
"""
if not isinstance(
attribute_container, containers_interface.AttributeContainer):
raise TypeError('{0:s} is not an attribute container type.'.format(
type(attribute_container)))
container_type = getattr(attribute_container, 'CONTAINER_TYPE', None)
if not container_type:
raise ValueError('Unsupported attribute container type: {0:s}.'.format(
type(attribute_container)))
json_dict = {
'__type__': 'AttributeContainer',
'__container_type__': container_type,
}
for attribute_name, attribute_value in attribute_container.GetAttributes():
json_dict[attribute_name] = cls._ConvertAttributeValueToDict(
attribute_value)
return json_dict
# Pylint is confused by the formatting of the return type.
# pylint: disable=missing-return-type-doc
@classmethod
def _ConvertAttributeValueToDict(cls, attribute_value):
"""Converts an attribute value into a JSON dictionary.
Args:
attribute_value (object): an attribute value.
Returns:
dict|list: The JSON serialized object which can be a dictionary or a list.
"""
if isinstance(attribute_value, py2to3.BYTES_TYPE):
encoded_value = binascii.b2a_qp(attribute_value)
encoded_value = codecs.decode(encoded_value, 'ascii')
attribute_value = {
'__type__': 'bytes',
'stream': '{0:s}'.format(encoded_value)
}
elif isinstance(attribute_value, (list, tuple)):
json_list = []
for list_element in attribute_value:
json_dict = cls._ConvertAttributeValueToDict(list_element)
json_list.append(json_dict)
if isinstance(attribute_value, list):
attribute_value = json_list
else:
attribute_value = {
'__type__': 'tuple',
'values': json_list
}
elif isinstance(attribute_value, collections.Counter):
attribute_value = cls._ConvertCollectionsCounterToDict(attribute_value)
elif isinstance(attribute_value, dfvfs_path_spec.PathSpec):
attribute_value = cls._ConvertPathSpecToDict(attribute_value)
elif isinstance(attribute_value, containers_interface.AttributeContainer):
attribute_value = cls._ConvertAttributeContainerToDict(attribute_value)
return attribute_value
@classmethod
def _ConvertCollectionsCounterToDict(cls, collections_counter):
"""Converts a collections.Counter object into a JSON dictionary.
The resulting dictionary of the JSON serialized objects consists of:
{
'__type__': 'collections.Counter'
...
}
Here '__type__' indicates the object base type. In this case
'collections.Counter'. The rest of the elements of the dictionary make up
the collections.Counter object attributes.
Args:
collections_counter (collections.Counter): counter.
Returns:
dict[str, object]: JSON serialized objects.
Raises:
TypeError: if not an instance of collections.Counter.
"""
if not isinstance(collections_counter, collections.Counter):
raise TypeError
json_dict = {'__type__': 'collections.Counter'}
for attribute_name, attribute_value in iter(collections_counter.items()):
if attribute_value is None:
continue
if isinstance(attribute_value, py2to3.BYTES_TYPE):
attribute_value = {
'__type__': 'bytes',
'stream': '{0:s}'.format(binascii.b2a_qp(attribute_value))
}
json_dict[attribute_name] = attribute_value
return json_dict
# Pylint is confused by the formatting of the return type.
# pylint: disable=missing-return-type-doc
@classmethod
def _ConvertDictToObject(cls, json_dict):
"""Converts a JSON dict into an object.
The dictionary of the JSON serialized objects consists of:
{
'__type__': 'AttributeContainer'
'__container_type__': ...
...
}
Here '__type__' indicates the object base type. In this case
'AttributeContainer'.
'__container_type__' indicates the attribute container type.
The rest of the elements of the dictionary make up the attributes.
Args:
json_dict (dict[str, object]): JSON serialized objects.
Returns:
AttributeContainer|dict|list|tuple: deserialized object.
Raises:
ValueError: if the class type or container type is not supported.
"""
# Use __type__ to indicate the object class type.
class_type = json_dict.get('__type__', None)
if not class_type:
# Dealing with a regular dict.
return json_dict
if class_type == 'bytes':
return binascii.a2b_qp(json_dict['stream'])
elif class_type == 'tuple':
return tuple(cls._ConvertListToObject(json_dict['values']))
elif class_type == 'collections.Counter':
return cls._ConvertDictToCollectionsCounter(json_dict)
elif class_type == 'AttributeContainer':
# Use __container_type__ to indicate the attribute container type.
container_type = json_dict.get('__container_type__', None)
# Since we would like the JSON as flat as possible we handle decoding
# a path specification.
elif class_type == 'PathSpec':
return cls._ConvertDictToPathSpec(json_dict)
else:
raise ValueError('Unsupported class type: {0:s}'.format(class_type))
container_class = (
containers_manager.AttributeContainersManager.GetAttributeContainer(
container_type))
if not container_class:
raise ValueError('Unsupported container type: {0:s}'.format(
container_type))
container_object = container_class()
supported_attribute_names = container_object.GetAttributeNames()
for attribute_name, attribute_value in iter(json_dict.items()):
# Be strict about which attributes to set in non event values.
if (container_type not in ('event', 'event_data') and
attribute_name not in supported_attribute_names):
if attribute_name not in ('__container_type__', '__type__'):
logger.debug((
'[ConvertDictToObject] unsupported attribute name: '
'{0:s}.{1:s}').format(container_type, attribute_name))
continue
if isinstance(attribute_value, dict):
attribute_value = cls._ConvertDictToObject(attribute_value)
elif isinstance(attribute_value, list):
attribute_value = cls._ConvertListToObject(attribute_value)
setattr(container_object, attribute_name, attribute_value)
return container_object
@classmethod
def _ConvertDictToCollectionsCounter(cls, json_dict):
"""Converts a JSON dict into a collections.Counter.
The dictionary of the JSON serialized objects consists of:
{
'__type__': 'collections.Counter'
...
}
Here '__type__' indicates the object base type. In this case this should
be 'collections.Counter'. The rest of the elements of the dictionary make up
the preprocessing object properties.
Args:
json_dict (dict[str, object]): JSON serialized objects.
Returns:
collections.Counter: counter.
"""
collections_counter = collections.Counter()
for key, value in iter(json_dict.items()):
if key == '__type__':
continue
collections_counter[key] = value
return collections_counter
@classmethod
def _ConvertListToObject(cls, json_list):
"""Converts a JSON list into an object.
Args:
json_list (list[object]): JSON serialized objects.
Returns:
list[object]: a deserialized list.
"""
list_value = []
for json_list_element in json_list:
if isinstance(json_list_element, dict):
list_value.append(cls._ConvertDictToObject(json_list_element))
elif isinstance(json_list_element, list):
list_value.append(cls._ConvertListToObject(json_list_element))
else:
list_value.append(json_list_element)
return list_value
@classmethod
def _ConvertDictToPathSpec(cls, json_dict):
"""Converts a JSON dict into a path specification object.
The dictionary of the JSON serialized objects consists of:
{
'__type__': 'PathSpec'
'type_indicator': 'OS'
'parent': { ... }
...
}
Here '__type__' indicates the object base type. In this case this should
be 'PathSpec'. The rest of the elements of the dictionary make up the
path specification object properties.
Args:
json_dict (dict[str, object]): JSON serialized objects.
Returns:
path.PathSpec: path specification.
"""
type_indicator = json_dict.get('type_indicator', None)
if type_indicator:
del json_dict['type_indicator']
if 'parent' in json_dict:
json_dict['parent'] = cls._ConvertDictToPathSpec(json_dict['parent'])
# Remove the class type from the JSON dict since we cannot pass it.
del json_dict['__type__']
return dfvfs_path_spec_factory.Factory.NewPathSpec(
type_indicator, **json_dict)
@classmethod
def _ConvertPathSpecToDict(cls, path_spec_object):
"""Converts a path specification object into a JSON dictionary.
The resulting dictionary of the JSON serialized objects consists of:
{
'__type__': 'PathSpec'
'type_indicator': 'OS'
'parent': { ... }
...
}
Here '__type__' indicates the object base type. In this case 'PathSpec'.
The rest of the elements of the dictionary make up the path specification
object properties. The supported property names are defined in
path_spec_factory.Factory.PROPERTY_NAMES. Note that this method is called
recursively for every path specification object and creates a dict of
dicts in the process.
Args:
path_spec_object (dfvfs.PathSpec): path specification.
Returns:
dict[str, object]: JSON serialized objects.
Raises:
TypeError: if not an instance of dfvfs.PathSpec.
"""
if not isinstance(path_spec_object, dfvfs_path_spec.PathSpec):
raise TypeError
json_dict = {'__type__': 'PathSpec'}
for property_name in dfvfs_path_spec_factory.Factory.PROPERTY_NAMES:
property_value = getattr(path_spec_object, property_name, None)
if property_value is not None:
json_dict[property_name] = property_value
if path_spec_object.HasParent():
json_dict['parent'] = cls._ConvertPathSpecToDict(path_spec_object.parent)
json_dict['type_indicator'] = path_spec_object.type_indicator
location = getattr(path_spec_object, 'location', None)
if location:
json_dict['location'] = location
return json_dict
[docs] @classmethod
def ReadSerialized(cls, json_string): # pylint: disable=arguments-differ
"""Reads an attribute container from serialized form.
Args:
json_string (str): JSON serialized attribute container.
Returns:
AttributeContainer: attribute container or None.
"""
if json_string:
json_dict = json.loads(json_string)
return cls.ReadSerializedDict(json_dict)
return None
[docs] @classmethod
def ReadSerializedDict(cls, json_dict):
"""Reads an attribute container from serialized dictionary form.
Args:
json_dict (dict[str, object]): JSON serialized objects.
Returns:
AttributeContainer: attribute container or None.
Raises:
TypeError: if the serialized dictionary does not contain an
AttributeContainer.
"""
if json_dict:
json_object = cls._ConvertDictToObject(json_dict)
if not isinstance(json_object, containers_interface.AttributeContainer):
raise TypeError('{0:s} is not an attribute container type.'.format(
type(json_object)))
return json_object
return None
[docs] @classmethod
def WriteSerialized(cls, attribute_container):
"""Writes an attribute container to serialized form.
Args:
attribute_container (AttributeContainer): attribute container.
Returns:
str: A JSON string containing the serialized form.
"""
json_dict = cls.WriteSerializedDict(attribute_container)
return json.dumps(json_dict)
[docs] @classmethod
def WriteSerializedDict(cls, attribute_container):
"""Writes an attribute container to serialized form.
Args:
attribute_container (AttributeContainer): attribute container.
Returns:
dict[str, object]: JSON serialized objects.
"""
return cls._ConvertAttributeContainerToDict(attribute_container)