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 decimal

     9 import yaml

    10 

    11 from django.db import models

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

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

    14 

    15 class DjangoSafeDumper(yaml.SafeDumper):

    16     def represent_decimal(self, data):

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

    18 

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

    20 

    21 class Serializer(PythonSerializer):

    22     """

    23     Convert a queryset to YAML.

    24     """

    25 

    26     internal_use_only = False

    27 

    28     def handle_field(self, obj, field):

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

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

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

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

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

    34         # halt deserialization under any other language.

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

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

    37         else:

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

    39 

    40     def end_serialization(self):

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

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

    43         self.options.pop('use_natural_keys', None)

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

    45 

    46     def getvalue(self):

    47         return self.stream.getvalue()

    48 

    49 def Deserializer(stream_or_string, **options):

    50     """

    51     Deserialize a stream or string of YAML data.

    52     """

    53     if isinstance(stream_or_string, basestring):

    54         stream = StringIO(stream_or_string)

    55     else:

    56         stream = stream_or_string

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

    58         yield obj

    59