def default_union_serializer(obj: object, cls: Union, **kwargs) -> object:
"""
Serialize an object to any matching type of the given union. The first
successful serialization is returned.
:param obj: The object that is to be serialized.
:param cls: The Union type with a generic (e.g. Union[str, int]).
:param kwargs: Any keyword arguments that are passed through the
serialization process.
:return: An object of the first type of the Union that could be
serialized successfully.
"""
sub_types = get_union_params(cls)
# Cater for Optional[...]/Union[None, ...] first to avoid blindly
# string-ifying None in later serializers.
if obj is None and NoneType in sub_types:
return obj
for sub_type in sub_types:
try:
return dump(obj, sub_type, **kwargs)
except JsonsError:
pass # Try the next one.
else:
args_msg = ', '.join(
[get_class_name(cls_) for cls_ in get_union_params(cls)])
err_msg = ('Could not match the object of type "{}" to any type of '
'the Union: {}'.format(type(obj), args_msg))
raise SerializationError(err_msg)
def default_union_deserializer(obj: object, cls: Union, **kwargs) -> object:
"""
Deserialize an object to any matching type of the given union. The first
successful deserialization is returned.
:param obj: The object that needs deserializing.
:param cls: The Union type with a generic (e.g. Union[str, int]).
:param kwargs: Any keyword arguments that are passed through the
deserialization process.
:return: An object of the first type of the Union that could be
deserialized successfully.
"""
for sub_type in get_union_params(cls):
try:
return load(obj, sub_type, **kwargs)
except JsonsError:
pass # Try the next one.
else:
fork_inst = kwargs['fork_inst']
args_msg = ', '.join([
get_class_name(cls_, fork_inst=fork_inst)
for cls_ in get_union_params(cls)
])
err_msg = ('Could not match the object of type "{}" to any type of '
'the Union: {}'.format(str(cls), args_msg))
raise DeserializationError(err_msg, obj, cls)
def can_match_with_none(cls: type):
# Return True if cls allows None; None is a valid value with the given cls.
result = cls in (Any, object, None, NoneType)
if not result:
cls_name = get_class_name(cls).lower()
result = 'union' in cls_name and NoneType in get_union_params(cls)
return result
def default_namedtuple_deserializer(obj: Union[list, dict], cls: type,
**kwargs) -> object:
"""
Deserialize a (JSON) list or dict into a named tuple by deserializing all
items of that list/dict.
:param obj: the tuple that needs deserializing.
:param cls: the NamedTuple.
:param kwargs: any keyword arguments.
:return: a deserialized named tuple (i.e. an instance of a class).
"""
is_dict = isinstance(obj, dict)
args = []
for index, field_name in enumerate(cls._fields):
if index < len(obj):
key = field_name if is_dict else index
field = obj[key]
else:
field = cls._field_defaults.get(field_name, None)
if field is None:
hint = getattr(cls, '_field_types', {}).get(field_name)
if type(None) not in (get_union_params(hint) or []):
# The value 'None' is not permitted here.
msg = ('No value present in {} for argument "{}"'.format(
obj, field_name))
raise UnfulfilledArgumentError(msg, field_name, obj, cls)
field_types = getattr(cls, '_field_types', None)
cls_ = field_types.get(field_name) if field_types else None
loaded_field = load(field, cls_, **kwargs)
args.append(loaded_field)
inst = cls(*args)
return inst
def default_namedtuple_deserializer(obj: Union[list, dict],
cls: type,
*,
key_transformer: Optional[Callable[
[str], str]] = None,
**kwargs) -> object:
"""
Deserialize a (JSON) list or dict into a named tuple by deserializing all
items of that list/dict.
:param obj: the tuple that needs deserializing.
:param cls: the NamedTuple.
:param kwargs: any keyword arguments.
:return: a deserialized named tuple (i.e. an instance of a class).
"""
is_dict = isinstance(obj, dict)
key_tfr = key_transformer or (lambda key: key)
if is_dict:
tfm_obj = {key_tfr(k): v for k, v in obj.items()}
args = []
for index, field_name in enumerate(cls._fields):
if index < len(obj):
if is_dict:
field = tfm_obj[field_name]
else:
field = obj[index]
else:
field = cls._field_defaults.get(field_name, None)
# _field_types has been deprecated in favor of __annotations__ in Python 3.8
if hasattr(cls, '__annotations__'):
field_types = getattr(cls, '__annotations__', {})
else:
field_types = getattr(cls, '_field_types', {})
if field is None:
hint = field_types.get(field_name)
if NoneType not in (get_union_params(hint) or []):
# The value 'None' is not permitted here.
msg = ('No value present in {} for argument "{}"'.format(
obj, field_name))
raise UnfulfilledArgumentError(msg, field_name, obj, cls)
cls_ = field_types.get(field_name) if field_types else None
loaded_field = load(field,
cls_,
key_transformer=key_transformer,
**kwargs)
args.append(loaded_field)
inst = cls(*args)
return inst
