112 lines
3.5 KiB
Python
112 lines
3.5 KiB
Python
"""
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Serialize data to/from JSON
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"""
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import datetime
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import decimal
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import json
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import uuid
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from django.core.serializers.base import DeserializationError
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from django.core.serializers.python import (
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Deserializer as PythonDeserializer, Serializer as PythonSerializer,
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)
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from django.utils.duration import duration_iso_string
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from django.utils.functional import Promise
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from django.utils.timezone import is_aware
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class Serializer(PythonSerializer):
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"""
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Convert a queryset to JSON.
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"""
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internal_use_only = False
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def _init_options(self):
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if json.__version__.split('.') >= ['2', '1', '3']:
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# Use JS strings to represent Python Decimal instances (ticket #16850)
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self.options.update({'use_decimal': False})
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self._current = None
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self.json_kwargs = self.options.copy()
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self.json_kwargs.pop('stream', None)
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self.json_kwargs.pop('fields', None)
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if self.options.get('indent'):
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# Prevent trailing spaces
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self.json_kwargs['separators'] = (',', ': ')
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self.json_kwargs.setdefault('cls', DjangoJSONEncoder)
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def start_serialization(self):
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self._init_options()
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self.stream.write("[")
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def end_serialization(self):
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if self.options.get("indent"):
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self.stream.write("\n")
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self.stream.write("]")
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if self.options.get("indent"):
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self.stream.write("\n")
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def end_object(self, obj):
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# self._current has the field data
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indent = self.options.get("indent")
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if not self.first:
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self.stream.write(",")
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if not indent:
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self.stream.write(" ")
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if indent:
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self.stream.write("\n")
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json.dump(self.get_dump_object(obj), self.stream, **self.json_kwargs)
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self._current = None
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def getvalue(self):
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# Grandparent 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 JSON data.
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"""
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if not isinstance(stream_or_string, (bytes, str)):
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stream_or_string = stream_or_string.read()
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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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try:
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objects = json.loads(stream_or_string)
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for obj in PythonDeserializer(objects, **options):
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yield obj
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except (GeneratorExit, DeserializationError):
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raise
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except Exception as exc:
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raise DeserializationError() from exc
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class DjangoJSONEncoder(json.JSONEncoder):
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"""
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JSONEncoder subclass that knows how to encode date/time, decimal types and UUIDs.
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"""
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def default(self, o):
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# See "Date Time String Format" in the ECMA-262 specification.
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if isinstance(o, datetime.datetime):
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r = o.isoformat()
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if o.microsecond:
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r = r[:23] + r[26:]
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if r.endswith('+00:00'):
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r = r[:-6] + 'Z'
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return r
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elif isinstance(o, datetime.date):
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return o.isoformat()
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elif isinstance(o, datetime.time):
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if is_aware(o):
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raise ValueError("JSON can't represent timezone-aware times.")
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r = o.isoformat()
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if o.microsecond:
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r = r[:12]
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return r
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elif isinstance(o, datetime.timedelta):
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return duration_iso_string(o)
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elif isinstance(o, (decimal.Decimal, uuid.UUID, Promise)):
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return str(o)
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else:
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return super().default(o)
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