"""
Serialize data to/from JSON
"""
import datetime
import decimal
import json
import uuid
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
from django.utils.duration import duration_iso_string
from django.utils.functional import Promise
from django.utils.timezone import is_aware
class Serializer(PythonSerializer):
"""Convert a queryset to JSON."""
internal_use_only = False
def _init_options(self):
self._current = None
self.json_kwargs = self.options.copy()
self.json_kwargs.pop("stream", None)
self.json_kwargs.pop("fields", None)
if self.options.get("indent"):
# Prevent trailing spaces
self.json_kwargs["separators"] = (",", ": ")
self.json_kwargs.setdefault("cls", DjangoJSONEncoder)
self.json_kwargs.setdefault("ensure_ascii", False)
def start_serialization(self):
self._init_options()
self.stream.write("[")
def end_serialization(self):
if self.options.get("indent"):
self.stream.write("\n")
self.stream.write("]")
if self.options.get("indent"):
self.stream.write("\n")
def end_object(self, obj):
# self._current has the field data
indent = self.options.get("indent")
if not self.first:
self.stream.write(",")
if not indent:
self.stream.write(" ")
if indent:
self.stream.write("\n")
json.dump(self.get_dump_object(obj), self.stream, **self.json_kwargs)
self._current = None
def getvalue(self):
# Grandparent super
return super(PythonSerializer, self).getvalue()
def Deserializer(stream_or_string, **options):
"""Deserialize a stream or string of JSON data."""
if not isinstance(stream_or_string, (bytes, str)):
stream_or_string = stream_or_string.read()
if isinstance(stream_or_string, bytes):
stream_or_string = stream_or_string.decode()
try:
objects = json.loads(stream_or_string)
yield from PythonDeserializer(objects, **options)
except (GeneratorExit, DeserializationError):
raise
except Exception as exc:
raise DeserializationError() from exc
class DjangoJSONEncoder(json.JSONEncoder):
"""
JSONEncoder subclass that knows how to encode date/time, decimal types, and
UUIDs.
"""
def default(self, o):
# See "Date Time String Format" in the ECMA-262 specification.
if isinstance(o, datetime.datetime):
r = o.isoformat()
if o.microsecond:
r = r[:23] + r[26:]
if r.endswith("+00:00"):
r = r[:-6] + "Z"
return r
elif isinstance(o, datetime.date):
return o.isoformat()
elif isinstance(o, datetime.time):
if is_aware(o):
raise ValueError("JSON can't represent timezone-aware times.")
r = o.isoformat()
if o.microsecond:
r = r[:12]
return r
elif isinstance(o, datetime.timedelta):
return duration_iso_string(o)
elif isinstance(o, (decimal.Decimal, uuid.UUID, Promise)):
return str(o)
else:
return super().default(o)