Tooltron

"""

Serialize data to/from JSON

"""

import datetime

import decimal

from StringIO import StringIO

from django.core.serializers.base import DeserializationError

from django.core.serializers.python import Serializer as PythonSerializer

from django.core.serializers.python import Deserializer as PythonDeserializer

from django.utils import simplejson

from django.utils.timezone import is_aware

class Serializer(PythonSerializer):

    """

    Convert a queryset to JSON.

    """

    internal_use_only = False

    def end_serialization(self):

        if simplejson.__version__.split('.') >= ['2', '1', '3']:

            # Use JS strings to represent Python Decimal instances (ticket #16850)

            self.options.update({'use_decimal': False})

        simplejson.dump(self.objects, self.stream, cls=DjangoJSONEncoder, **self.options)

    def getvalue(self):

        if callable(getattr(self.stream, 'getvalue', None)):

            return self.stream.getvalue()

def Deserializer(stream_or_string, **options):

    """

    Deserialize a stream or string of JSON data.

    """

    if isinstance(stream_or_string, basestring):

        stream = StringIO(stream_or_string)

    else:

        stream = stream_or_string

    try:

        for obj in PythonDeserializer(simplejson.load(stream), **options):

            yield obj

    except GeneratorExit:

        raise

    except Exception, e:

        # Map to deserializer error

        raise DeserializationError(e)

class DjangoJSONEncoder(simplejson.JSONEncoder):

    """

    JSONEncoder subclass that knows how to encode date/time and decimal types.

    """

    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, decimal.Decimal):

            return str(o)

        else:

            return super(DjangoJSONEncoder, self).default(o)

# Older, deprecated class name (for backwards compatibility purposes).

DateTimeAwareJSONEncoder = DjangoJSONEncoder