78 lines
2.6 KiB
Python
78 lines
2.6 KiB
Python
"""
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YAML serializer.
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Requires PyYaml (http://pyyaml.org/), but that's checked for in __init__.
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"""
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import decimal
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import yaml
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import sys
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from io import StringIO
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from django.db import models
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from django.core.serializers.base import DeserializationError
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from django.core.serializers.python import Serializer as PythonSerializer
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from django.core.serializers.python import Deserializer as PythonDeserializer
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from django.utils import six
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# Use the C (faster) implementation if possible
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try:
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from yaml import CSafeLoader as SafeLoader
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from yaml import CSafeDumper as SafeDumper
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except ImportError:
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from yaml import SafeLoader, SafeDumper
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class DjangoSafeDumper(SafeDumper):
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def represent_decimal(self, data):
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return self.represent_scalar('tag:yaml.org,2002:str', str(data))
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DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)
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class Serializer(PythonSerializer):
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"""
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Convert a queryset to YAML.
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"""
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internal_use_only = False
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def handle_field(self, obj, field):
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# A nasty special case: base YAML doesn't support serialization of time
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# types (as opposed to dates or datetimes, which it does support). Since
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# we want to use the "safe" serializer for better interoperability, we
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# need to do something with those pesky times. Converting 'em to strings
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# isn't perfect, but it's better than a "!!python/time" type which would
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# halt deserialization under any other language.
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if isinstance(field, models.TimeField) and getattr(obj, field.name) is not None:
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self._current[field.name] = str(getattr(obj, field.name))
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else:
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super(Serializer, self).handle_field(obj, field)
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def end_serialization(self):
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yaml.dump(self.objects, self.stream, Dumper=DjangoSafeDumper, **self.options)
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def getvalue(self):
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# Grand-parent super
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return super(PythonSerializer, self).getvalue()
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def Deserializer(stream_or_string, **options):
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"""
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Deserialize a stream or string of YAML data.
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"""
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if isinstance(stream_or_string, bytes):
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stream_or_string = stream_or_string.decode('utf-8')
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if isinstance(stream_or_string, six.string_types):
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stream = StringIO(stream_or_string)
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else:
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stream = stream_or_string
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try:
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for obj in PythonDeserializer(yaml.load(stream, Loader=SafeLoader), **options):
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yield obj
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except GeneratorExit:
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raise
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except Exception as e:
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# Map to deserializer error
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six.reraise(DeserializationError, DeserializationError(e), sys.exc_info()[2])
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