def _get_value_for_attr(
obj,
cls,
orig_cls,
sig_key,
sig,
meta_hints,
attr_getters,
**kwargs):
# Find a value for the attribute (with signature sig_key).
if obj and sig_key in obj:
# This argument is in obj.
result = sig_key, _get_value_from_obj(obj, cls, sig, sig_key,
meta_hints, **kwargs)
elif sig_key in attr_getters:
# There exists an attr_getter for this argument.
attr_getter = attr_getters.pop(sig_key)
result = sig_key, attr_getter()
elif sig.default != inspect.Parameter.empty:
# There is a default value for this argument.
result = sig_key, sig.default
elif sig.kind in (inspect.Parameter.VAR_POSITIONAL,
inspect.Parameter.VAR_KEYWORD):
# This argument is either *args or **kwargs.
result = None, None
elif can_match_with_none(cls):
# It is fine that there is no value.
result = sig_key, None
else:
raise UnfulfilledArgumentError(
'No value found for "{}"'.format(sig_key), sig_key, obj, orig_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
def _get_value_for_attr(obj, cls, sig_key, sig, attr_getters, **kwargs):
result = None, None
if obj and sig_key in obj:
# This argument is in obj.
arg_cls = None
if sig.annotation != inspect.Parameter.empty:
arg_cls = sig.annotation
value = load(obj[sig_key], arg_cls, **kwargs)
result = sig_key, value
elif sig_key in attr_getters:
# There exists an attr_getter for this argument.
attr_getter = attr_getters.pop(sig_key)
result = sig_key, attr_getter()
elif sig.default != inspect.Parameter.empty:
# There is a default value for this argument.
result = sig_key, sig.default
elif sig.kind not in (inspect.Parameter.VAR_POSITIONAL,
inspect.Parameter.VAR_KEYWORD):
# This argument is no *args or **kwargs and has no value.
raise UnfulfilledArgumentError(
'No value found for "{}"'.format(sig_key), sig_key, obj, cls)
return result
def default_namedtuple_deserializer(obj: list, cls: type, **kwargs) -> object:
"""
Deserialize a (JSON) list into a named tuple by deserializing all items of
that list.
: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).
"""
args = []
for index, field_name in enumerate(cls._fields):
if index < len(obj):
field = obj[index]
else:
field = cls._field_defaults.get(field_name, None)
if not field:
msg = ('No value present in {} for argument "{}"'
.format(obj, field_name))
raise UnfulfilledArgumentError(msg, field_name, obj, cls)
cls_ = cls._field_types.get(field_name, None)
loaded_field = load(field, cls_, **kwargs)
args.append(loaded_field)
inst = cls(*args)
return inst
