def _build_value(type_: Type, data: Any, config: Config) -> Any:
if is_union(type_):
return _build_value_for_union(union=type_, data=data, config=config)
elif is_generic_collection(type_) and is_instance(
data, extract_origin_collection(type_)):
return _build_value_for_collection(collection=type_,
data=data,
config=config)
elif is_dataclass(type_) and is_instance(data, Data):
return from_dict(data_class=type_, data=data, config=config)
return data
def from_dict(data_class: Type[T],
data: Data,
config: Optional[Config] = None) -> T:
"""Create a data class instance from a dictionary.
:param data_class: a data class type
:param data: a dictionary of a input data
:param config: a configuration of the creation process
:return: an instance of a data class
"""
init_values: Data = {}
post_init_values: Data = {}
config = config or Config()
try:
data_class_hints = get_type_hints(data_class,
globalns=config.forward_references)
except NameError as error:
raise ForwardReferenceError(str(error)) from error
data_class_fields = get_fields(data_class)
if config.strict:
extra_fields = set(data.keys()) - {f.name for f in data_class_fields}
if extra_fields:
raise UnexpectedDataError(keys=extra_fields)
for field in data_class_fields:
field = copy.copy(field)
field.type = data_class_hints[field.name]
try:
try:
field_data = data[field.name]
transformed_value = transform_value(
type_hooks=config.type_hooks,
cast=config.cast,
target_type=field.type,
value=field_data,
)
value = _build_value(type_=field.type,
data=transformed_value,
config=config)
except DaciteFieldError as error:
error.update_path(field.name)
raise
if config.check_types and not is_instance(value, field.type):
raise WrongTypeError(field_path=field.name,
field_type=field.type,
value=value)
except KeyError:
try:
value = get_default_value_for_field(field)
except DefaultValueNotFoundError as err:
if not field.init:
continue
raise MissingValueError(field.name) from err
if field.init:
init_values[field.name] = value
else:
post_init_values[field.name] = value
return create_instance(data_class=data_class,
init_values=init_values,
post_init_values=post_init_values)
def test_is_instance_with_not_supported_generic_types():
T = TypeVar("T")
class X(Generic[T]):
pass
assert not is_instance(X[str](), X[str])
def _build_value_for_union(union: Type, data: Any, config: Config) -> Any:
types = extract_generic(union)
if is_optional(union) and len(types) == 2:
return _build_value(type_=types[0], data=data, config=config)
union_matches = {}
for inner_type in types:
try:
# noinspection PyBroadException
try:
data = transform_value(
type_hooks=config.type_hooks,
cast=config.cast,
target_type=inner_type,
value=data,
)
except Exception: # pylint: disable=broad-except
continue
value = _build_value(type_=inner_type, data=data, config=config)
if is_instance(value, inner_type):
if config.strict_unions_match:
union_matches[inner_type] = value
else:
return value
except DaciteError:
pass
if config.strict_unions_match:
if len(union_matches) > 1:
raise StrictUnionMatchError(union_matches)
return union_matches.popitem()[1]
if not config.check_types:
return data
raise UnionMatchError(field_type=union, value=data)
def _build_value_for_collection(collection: Type, data: Any,
config: Config) -> Any:
if is_instance(data, Mapping):
return data.__class__(
(key,
_build_value(type_=extract_generic(collection)[1],
data=value,
config=config)) for key, value in data.items())
return data.__class__(
_build_value(
type_=extract_generic(collection)[0], data=item, config=config)
for item in data)
def test_is_instance_with_nested_generic_collection_and_not_matching_item_type(
):
assert not is_instance([["test"]], List[List[int]])
def test_is_instance_with_init_var_and_not_matching_value_type():
assert not is_instance(1, InitVar[str])
def test_is_instance_with_tuple_and_matching_type():
assert is_instance((1, "test"), Tuple[int, str])
def test_is_instance_with_variable_length_tuple_and_not_matching_type():
assert not is_instance((1, 2, "test"), Tuple[int, ...])
def test_is_instance_with_numeric_tower_and_new_type():
assert is_instance(1, NewType("NewType", float))
def test_is_instance_with_optional_literal_and_not_matching_type():
from typing import Literal
assert not is_instance("C", Optional[Literal["A", "B"]])
def test_is_instance_with_generic_mapping_and_not_matching_mapping_key_type():
assert not is_instance({1: 1}, Dict[str, int])
def test_is_instance_with_numeric_tower():
assert is_instance(1, float)
def test_is_instance_with_nested_generic_collection_and_matching_value_type():
assert is_instance([[1]], List[List[int]])
def test_is_instance_with_optional_and_not_matching_value_type():
assert not is_instance(1, Optional[str])
def test_is_instance_with_optional_and_matching_value_type():
assert is_instance(1, Optional[int])
def test_is_instance_with_union_and_not_matching_value_type():
assert not is_instance("test", Union[int, float])
def test_is_instance_with_built_in_type_and_not_matching_value_type():
assert not is_instance("test", int)
def test_is_instance_with_generic_mapping_and_not_matching_mapping_value_type(
):
assert not is_instance({"test": "test"}, Dict[str, int])
def test_is_instance_with_generic_collection_without_specified_inner_types_and_not_matching_value_type(
):
assert not is_instance([1], Dict)
def test_is_instance_with_numeric_tower_and_optional():
assert is_instance(1, Optional[float])
def test_is_instance_with_generic_abstract_collection_and_matching_value_type(
):
assert is_instance([1], Collection[int])
def test_is_instance_with_literal_and_matching_type():
from typing import Literal
assert is_instance("A", Literal["A", "B"])
def test_is_instance_with_generic_collection_and_not_matching_value_type():
assert not is_instance({1}, List[int])
def test_is_instance_with_optional_literal_and_none():
from typing import Literal
assert is_instance(None, Optional[Literal["A", "B"]])
def test_is_instance_with_any_type():
assert is_instance(1, Any)
def test_is_instance_with_tuple_and_not_matching_type():
assert not is_instance((1, 2), Tuple[int, str])
def test_is_instance_with_new_type_and_not_matching_value_type():
assert not is_instance(1, NewType("MyStr", str))
def test_is_instance_with_empty_tuple_and_not_matching_type():
assert not is_instance((1, 2), Tuple[()])
def test_is_instance_with_init_var_and_matching_value_type():
assert is_instance(1, InitVar[int])
