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"""
YAML serializer.
Requires PyYaml (https://pyyaml.org/), but that's checked for in __init__.
"""
import datetime
import decimal
import yaml
from django.core.serializers.base import DeserializationError
from django.core.serializers.python import Deserializer as PythonDeserializer
from django.core.serializers.python import Serializer as PythonSerializer
# Use the C (faster) implementation if possible
try:
from yaml import CSafeDumper as SafeDumper
from yaml import CSafeLoader as SafeLoader
except ImportError:
from yaml import SafeDumper, SafeLoader
class DjangoSafeDumper(SafeDumper):
# The "safe" serializer is used for better interoperability.
def represent_decimal(self, data):
return self.represent_scalar("tag:yaml.org,2002:str", str(data))
def represent_time(self, data):
# Base YAML doesn't support serialization of time types (as opposed to
# dates or datetimes, which it does support). Converting them to
# strings isn't perfect, but it's better than a "!!python/time" type
# which would prevent deserialization under any other language.
return self.represent_scalar("tag:yaml.org,2002:str", str(data))
DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)
DjangoSafeDumper.add_representer(datetime.time, DjangoSafeDumper.represent_time)
class Serializer(PythonSerializer):
"""Convert a queryset to YAML."""
internal_use_only = False
def end_serialization(self):
self.options.setdefault("allow_unicode", True)
yaml.dump(
self.objects,
self.stream,
Dumper=DjangoSafeDumper,
sort_keys=False,
**self.options,
)
def getvalue(self):
# Grandparent super
return super(PythonSerializer, self).getvalue()
class Deserializer(PythonDeserializer):
"""Deserialize a stream or string of YAML data."""
def __init__(self, stream_or_string, **options):
stream = stream_or_string
if isinstance(stream_or_string, bytes):
stream = stream_or_string.decode()
try:
objects = yaml.load(stream, Loader=SafeLoader)
except Exception as exc:
raise DeserializationError() from exc
super().__init__(objects, **options)
def _handle_object(self, obj):
try:
yield from super()._handle_object(obj)
except (GeneratorExit, DeserializationError):
raise
except Exception as exc:
raise DeserializationError(f"Error deserializing object: {exc}") from exc
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