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import inspect
from dataclasses import Field, replace
from types import new_class
from typing import (
Any,
Callable,
Dict,
Generic,
Iterable,
Mapping,
Optional,
Sequence,
Tuple,
Type,
TypeVar,
Union,
)
from apischema.methods import is_method, method_wrapper
from apischema.objects.fields import MISSING_DEFAULT, ObjectField, set_object_fields
from apischema.objects.getters import object_fields, parameters_as_fields
from apischema.type_names import type_name
from apischema.typing import get_type_hints
from apischema.utils import (
empty_dict,
substitute_type_vars,
subtyping_substitution,
to_pascal_case,
with_parameters,
)
T = TypeVar("T")
def object_deserialization(
func: Callable[..., T],
*input_class_modifiers: Callable[[type], Any],
parameters_metadata: Optional[Mapping[str, Mapping]] = None,
) -> Any:
fields = parameters_as_fields(func, parameters_metadata)
types = get_type_hints(func, include_extras=True)
if "return" not in types:
raise TypeError("Object deserialization must be typed")
return_type = types["return"]
bases = ()
if getattr(return_type, "__parameters__", ()):
bases = (Generic[return_type.__parameters__],) # type: ignore
elif func.__name__ != "<lambda>":
input_class_modifiers = (
type_name(to_pascal_case(func.__name__)),
*input_class_modifiers,
)
def __init__(self, **kwargs):
self.kwargs = kwargs
input_cls = new_class(
to_pascal_case(func.__name__),
bases,
exec_body=lambda ns: ns.update({"__init__": __init__}),
)
for modifier in input_class_modifiers:
modifier(input_cls)
set_object_fields(input_cls, fields)
if any(f.additional_properties for f in fields):
kwargs_param = next(f.name for f in fields if f.additional_properties)
def wrapper(input):
kwargs = input.kwargs.copy()
kwargs.update(kwargs.pop(kwargs_param))
return func(**kwargs)
else:
def wrapper(input):
return func(**input.kwargs)
wrapper.__annotations__["input"] = with_parameters(input_cls)
wrapper.__annotations__["return"] = return_type
return wrapper
def _fields_and_init(
cls: type, fields_and_methods: Union[Iterable[Any], Callable[[], Iterable[Any]]]
) -> Tuple[Sequence[ObjectField], Callable[[Any, Any], None]]:
fields = object_fields(cls, serialization=True)
output_fields: Dict[str, ObjectField] = {}
methods = []
if callable(fields_and_methods):
fields_and_methods = fields_and_methods()
for elt in fields_and_methods:
if elt is ...:
output_fields.update(fields)
continue
if isinstance(elt, tuple):
elt, metadata = elt
else:
metadata = empty_dict
if not isinstance(metadata, Mapping):
raise TypeError(f"Invalid metadata {metadata}")
if isinstance(elt, Field):
elt = elt.name
if isinstance(elt, str) and elt in fields:
elt = fields[elt]
if is_method(elt):
elt = method_wrapper(elt)
if isinstance(elt, ObjectField):
if metadata:
output_fields[elt.name] = replace(
elt, metadata={**elt.metadata, **metadata}, default=MISSING_DEFAULT
)
else:
output_fields[elt.name] = elt
continue
elif callable(elt):
types = get_type_hints(elt)
first_param = next(iter(inspect.signature(elt).parameters))
substitution, _ = subtyping_substitution(types.get(first_param, cls), cls)
ret = substitute_type_vars(types.get("return", Any), substitution)
output_fields[elt.__name__] = ObjectField(
elt.__name__, ret, metadata=metadata
)
methods.append((elt, output_fields[elt.__name__]))
else:
raise TypeError(f"Invalid serialization member {elt} for class {cls}")
serialized_methods = [m for m, f in methods if output_fields[f.name] is f]
serialized_fields = list(
output_fields.keys() - {m.__name__ for m in serialized_methods}
)
def __init__(self, obj):
for field in serialized_fields:
setattr(self, field, getattr(obj, field))
for method in serialized_methods:
setattr(self, method.__name__, method(obj))
return tuple(output_fields.values()), __init__
def object_serialization(
cls: Type[T],
fields_and_methods: Union[Iterable[Any], Callable[[], Iterable[Any]]],
*output_class_modifiers: Callable[[type], Any],
) -> Callable[[T], Any]:
generic, bases = cls, ()
if getattr(cls, "__parameters__", ()):
generic = cls[cls.__parameters__] # type: ignore
bases = Generic[cls.__parameters__] # type: ignore
elif (
callable(fields_and_methods)
and fields_and_methods.__name__ != "<lambda>"
and not getattr(cls, "__parameters__", ())
):
output_class_modifiers = (
type_name(to_pascal_case(fields_and_methods.__name__)),
*output_class_modifiers,
)
def __init__(self, obj):
_, new_init = _fields_and_init(cls, fields_and_methods)
new_init.__annotations__ = {"obj": generic}
output_cls.__init__ = new_init # type: ignore
new_init(self, obj)
__init__.__annotations__ = {"obj": generic}
output_cls = new_class(
f"{cls.__name__}Serialization",
bases,
exec_body=lambda ns: ns.update({"__init__": __init__}),
)
for modifier in output_class_modifiers:
modifier(output_cls)
set_object_fields(output_cls, lambda: _fields_and_init(cls, fields_and_methods)[0])
return output_cls
|
