app/django/core/serializers/pyyaml.py
author Madhusudan C.S. <madhusudancs@gmail.com>
Tue, 11 Aug 2009 12:48:10 -0700
changeset 2757 7d0d0ce76bd9
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
updateOrCreateFromFields is made to call updateOrCreateFromKeyName. updateOrCreateFromFields called self._model.get_or_insert which only creates new entities but doesn't update the properties if the entity already exists. So updateOrCreateFromFields is now made to call updateOrCreateFromKeyName which actually updates the entity properties if entity already exists. Reviewed by: Lennard de Rijk

"""
YAML serializer.

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

from StringIO import StringIO
import yaml

from django.db import models
from django.core.serializers.python import Serializer as PythonSerializer
from django.core.serializers.python import Deserializer as PythonDeserializer

class Serializer(PythonSerializer):
    """
    Convert a queryset to YAML.
    """
    
    internal_use_only = False
    
    def handle_field(self, obj, field):
        # A nasty special case: base YAML doesn't support serialization of time
        # types (as opposed to dates or datetimes, which it does support). Since
        # we want to use the "safe" serializer for better interoperability, we
        # need to do something with those pesky times. Converting 'em to strings
        # isn't perfect, but it's better than a "!!python/time" type which would
        # halt deserialization under any other language.
        if isinstance(field, models.TimeField) and getattr(obj, field.name) is not None:
            self._current[field.name] = str(getattr(obj, field.name))
        else:
            super(Serializer, self).handle_field(obj, field)
    
    def end_serialization(self):
        self.options.pop('stream', None)
        self.options.pop('fields', None)
        yaml.safe_dump(self.objects, self.stream, **self.options)

    def getvalue(self):
        return self.stream.getvalue()

def Deserializer(stream_or_string, **options):
    """
    Deserialize a stream or string of YAML data.
    """
    if isinstance(stream_or_string, basestring):
        stream = StringIO(stream_or_string)
    else:
        stream = stream_or_string
    for obj in PythonDeserializer(yaml.load(stream)):
        yield obj