django1/django/core/serializers/pyyaml.py

86 lines
2.8 KiB
Python

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