revision with json serialized_data fails upon DateField

Hi!

my reversioned model contains a DateField called “date”. Django-reversion used to, and still does, work fine with that model if the serialized_data is xml. With json serialized_data it fails: see exception added below, reproduced in manage.py shell.

I narrowed down the problem to wrong json data: django-reverison produces a revision whith json serialized_data which contains “date”: “2011-05-05 00:00:00”. So if i change that to “date”: “2011-05-05” everything’s back to normal.

/path/to/latest/reversion/models.pyc in get_object_version(self)
    187         if isinstance(data, unicode):
    188             data = data.encode("utf8")
--> 189         return list(serializers.deserialize(self.format, data))[0]
    190 
    191     object_version = property(get_object_version,

/usr/lib/pymodules/python2.7/django/core/serializers/json.pyc in Deserializer(stream_or_string, **options)
     33     else:
     34         stream = stream_or_string
---> 35     for obj in PythonDeserializer(simplejson.load(stream), **options):
     36         yield obj
     37 

/usr/lib/pymodules/python2.7/django/core/serializers/python.pyc in Deserializer(object_list, **options)
    126             # Handle all other fields
    127             else:
--> 128                 data[field.name] = field.to_python(field_value)
    129 
    130         yield base.DeserializedObject(Model(**data), m2m_data)

/usr/lib/pymodules/python2.7/django/db/models/fields/__init__.pyc in to_python(self, value)
    609 
    610         if not ansi_date_re.search(value):
--> 611             raise exceptions.ValidationError(self.error_messages['invalid'])
    612         # Now that we have the date string in YYYY-MM-DD format, check to make

    613         # sure it's a valid date.


ValidationError: [u'Enter a valid date in YYYY-MM-DD format.']

[etianen]

I’d still strongly suggest finding the bit of your code that’s assigning a string to a datetime field, and fixing the root problem there.

Sure, parts of Django are okay with this, but other parts are not.

On 30 July 2018 at 18:32, Jesús Avellaneda Menchón <[e-mail]

wrote:

Hi,

I don’t know if this is still a problem with recent versions of Django or Reversion, but I solved this issue for my company overriding the Django’s JSON deserializer.

1. Create a module fixing the problem in the deserializer:

#!/usr/bin/env python# -- coding: utf-8 -- from django.core.serializers.json import *from django.core.serializers.python import _get_modelfrom django.utils.dateparse import parse_datetimefrom django.db import modelsfrom copy import deepcopy

def _fix_datefield_with_datetime_deserialization(objects): # Si a un DateField se le quiere deserializar un datetime, # se debe eliminar la parte del tiempo para evitar errores # del tipo: DeserializationError: [u"El valor ‘2018-06-04T00:00:00’ # tiene formato de fecha inválido. Debe ser de la forma YYYY-MM-DD."] new_objects = deepcopy(objects) models.get_apps()

for i, d in enumerate(objects):
    model = _get_model(d['model'])

    for field_name, field_value in d['fields'].iteritems():
        # noinspection PyProtectedMember
        field = model._meta.get_field(field_name)

        if field_value and type(field) == models.DateField:
            parsed = parse_datetime(field_value)

            if parsed:
                new_objects[i]['fields'][field_name] = parsed.date().isoformat()

return new_objects

def Deserializer(stream_or_string, **options): “”" Deserialize a stream or string of JSON data. “”" if not isinstance(stream_or_string, (bytes, six.string_types)): stream_or_string = stream_or_string.read() if isinstance(stream_or_string, bytes): stream_or_string = stream_or_string.decode(‘utf-8’) try: objects = json.loads(stream_or_string) objects = _fix_datefield_with_datetime_deserialization(objects)

    for obj in PythonDeserializer(objects, **options):
        yield obj

except GeneratorExit:
    raise
except Exception as e:
    # Map to deserializer error
    raise DeserializationError(e)

1. Use this serialization module on your settings.py

SERIALIZATION_MODULES = {‘json’: ‘common.json_serializers’}

It might be a bit hacky, but I found it to be the only feasible way for us to get rid of the problem. I hope it helps!

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[jeaveme]

Thanks for your answer and this amazing library!

You are absolutely right, the best solution is fixing the root problem. However, let me make clear that the problem is caused for assigning a datetime to date field and that we haven’t detected any noticeable side effect after applying this workaround.

Thanks again!