app/django/core/serializers/pyyaml.py
author Sverre Rabbelier <srabbelier@gmail.com>
Sat, 12 Sep 2009 00:36:49 +0200
changeset 2898 ac5f77cd6046
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Fix 500 when saving /site/edit without email When saving /site/edit with no no_reply_email set, a 500 error page would be returned due to an empty value being passed as value to the datastore (which is not allowed for email fields).

"""
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