1 """

     2 Serialize data to/from JSON

     3 """

     4 

     5 import datetime

     6 from django.utils import simplejson

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

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

     9 try:

    10     from cStringIO import StringIO

    11 except ImportError:

    12     from StringIO import StringIO

    13 try:

    14     import decimal

    15 except ImportError:

    16     from django.utils import _decimal as decimal    # Python 2.3 fallback

    17 

    18 class Serializer(PythonSerializer):

    19     """

    20     Convert a queryset to JSON.

    21     """

    22     internal_use_only = False

    23     

    24     def end_serialization(self):

    25         self.options.pop('stream', None)

    26         self.options.pop('fields', None)

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

    28 

    29     def getvalue(self):

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

    31             return self.stream.getvalue()

    32 

    33 def Deserializer(stream_or_string, **options):

    34     """

    35     Deserialize a stream or string of JSON data.

    36     """

    37     if isinstance(stream_or_string, basestring):

    38         stream = StringIO(stream_or_string)

    39     else:

    40         stream = stream_or_string

    41     for obj in PythonDeserializer(simplejson.load(stream)):

    42         yield obj

    43 

    44 class DjangoJSONEncoder(simplejson.JSONEncoder):

    45     """

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

    47     """

    48 

    49     DATE_FORMAT = "%Y-%m-%d"

    50     TIME_FORMAT = "%H:%M:%S"

    51 

    52     def default(self, o):

    53         if isinstance(o, datetime.datetime):

    54             return o.strftime("%s %s" % (self.DATE_FORMAT, self.TIME_FORMAT))

    55         elif isinstance(o, datetime.date):

    56             return o.strftime(self.DATE_FORMAT)

    57         elif isinstance(o, datetime.time):

    58             return o.strftime(self.TIME_FORMAT)

    59         elif isinstance(o, decimal.Decimal):

    60             return str(o)

    61         else:

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

    63 

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

    65 DateTimeAwareJSONEncoder = DjangoJSONEncoder

    66