1 """

     2 YAML serializer.

     3 

     4 Requires PyYaml (http://pyyaml.org/), but that's checked for in __init__.

     5 """

     6 

     7 from StringIO import StringIO

     8 import yaml

     9 

    10 try:

    11     import decimal

    12 except ImportError:

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

    14 

    15 from django.db import models

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

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

    18 

    19 class DjangoSafeDumper(yaml.SafeDumper):

    20     def represent_decimal(self, data):

    21         return self.represent_scalar('tag:yaml.org,2002:str', str(data))

    22 

    23 DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)

    24 

    25 class Serializer(PythonSerializer):

    26     """

    27     Convert a queryset to YAML.

    28     """

    29     

    30     internal_use_only = False

    31     

    32     def handle_field(self, obj, field):

    33         # A nasty special case: base YAML doesn't support serialization of time

    34         # types (as opposed to dates or datetimes, which it does support). Since

    35         # we want to use the "safe" serializer for better interoperability, we

    36         # need to do something with those pesky times. Converting 'em to strings

    37         # isn't perfect, but it's better than a "!!python/time" type which would

    38         # halt deserialization under any other language.

    39         if isinstance(field, models.TimeField) and getattr(obj, field.name) is not None:

    40             self._current[field.name] = str(getattr(obj, field.name))

    41         else:

    42             super(Serializer, self).handle_field(obj, field)

    43     

    44     def end_serialization(self):

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

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

    47         yaml.dump(self.objects, self.stream, Dumper=DjangoSafeDumper, **self.options)

    48 

    49     def getvalue(self):

    50         return self.stream.getvalue()

    51 

    52 def Deserializer(stream_or_string, **options):

    53     """

    54     Deserialize a stream or string of YAML data.

    55     """

    56     if isinstance(stream_or_string, basestring):

    57         stream = StringIO(stream_or_string)

    58     else:

    59         stream = stream_or_string

    60     for obj in PythonDeserializer(yaml.load(stream)):

    61         yield obj

    62