def to_isoformat(value):
if value is None:
return None
try:
value = value.isoformat()
except AttributeError as error:
raise ValueSerializationError(error.args[0])
return value
def to_total_seconds(value):
if value is None:
return None
try:
value = value.total_seconds()
except AttributeError as error:
raise ValueSerializationError(error.args[0])
return value
def _get_serialized_value(self, format, attribute, config_set=None):
"""Retrieve the value of ``attribute`` after applying the attribute's
``on_serialize`` function for the format indicated by ``format``.
:param format: The format to which the value should be serialized. Accepts
either: ``csv``, ``json``, ``yaml``, or ``dict``.
:type format: :class:`str <python:str>`
:param attribute: The name of the attribute that whose serialized value
should be returned.
:type attribute: :class:`str <python:str>`
:param config_set: The name of the named configuration set whose configuration
should be used to retrieve the serialized value. Defaults to
:obj:`None <python:None>`.
:type config_set: :class:`str <python:str>` / :obj:`None <python:None>`
:returns: The value returned by the attribute's ``on_serialize`` function
for the indicated ``format``.
:raises InvalidFormatError: if ``format`` is not ``csv``, ``json``, ``yaml``,
or ``dict``.
:raises ValueSerializationError: if the ``on_serialize`` function raises
an exception
"""
# pylint: disable=line-too-long
to_csv, to_json, to_yaml, to_dict = format_to_tuple(format)
supports_serialization = self.does_support_serialization(
attribute,
to_csv=to_csv,
to_json=to_json,
to_yaml=to_yaml,
to_dict=to_dict,
config_set=config_set)
if not supports_serialization:
raise UnsupportedSerializationError(
"%s attribute '%s' does not support serialization to '%s'" %
(self.__class__, attribute, format))
config = self.get_attribute_serialization_config(attribute,
config_set=config_set)
on_serialize = config.on_serialize[format]
if on_serialize is None:
on_serialize = get_default_serializer(
getattr(self.__class__, attribute),
format=format,
value=getattr(self, attribute, None))
if on_serialize is None:
if format == 'csv':
return getattr(self, attribute, '')
return getattr(self, attribute, None)
try:
return_value = on_serialize(getattr(self, attribute, None))
except Exception:
raise ValueSerializationError(
"attribute '%s' failed serialization to format '%s'" %
(attribute, format))
return return_value