def deserialization() -> Conversion:
annotations: dict[str, Any] = {}
deserialization_namespace: dict[str, Any] = {
"__annotations__": annotations
}
for sub in rec_subclasses(cls):
annotations[sub.__name__] = Tagged[sub] # type: ignore
# Add tagged fields for all its alternative constructors
for constructor in _alternative_constructors.get(sub, ()):
# Build the alias of the field
alias = to_pascal_case(constructor.__name__)
# object_deserialization uses get_type_hints, but the constructor
# return type is stringified and the class not defined yet,
# so it must be assigned manually
constructor.__annotations__["return"] = sub
# Add constructor tagged field with its conversion
annotations[alias] = Tagged[sub] # type: ignore
deserialization_namespace[alias] = Tagged(
conversion(
# Use object_deserialization to wrap constructor as deserializer
deserialization=object_deserialization(
constructor, type_name(alias))))
# Create the deserialization tagged union class
deserialization_union = new_class(
cls.__name__,
(TaggedUnion, ),
exec_body=lambda ns: ns.update(deserialization_namespace),
)
return Conversion(lambda obj: get_tagged(obj)[1],
source=deserialization_union,
target=cls)
def conversion(self) -> Optional[Conversion]:
if self.serialization:
# Recursive conversion pattern
tmp = None
conversion = Conversion(self.serialization,
sub_conversion=LazyConversion(lambda: tmp))
tmp = conversion
return conversion
else:
return None
def default_deserialization(tp: Any) -> Optional[AnyConversion]:
if inspect.isclass(tp) and issubclass(tp, pydantic.BaseModel):
def deserialize_pydantic(data):
try:
return tp.parse_obj(data)
except pydantic.ValidationError as error:
raise ValidationError.from_errors(error.errors())
return Conversion(
deserialize_pydantic,
source=tp.__annotations__.get("__root__", Mapping[str, Any]),
target=tp,
)
else:
return prev_deserialization(tp)
def serialization() -> Conversion:
serialization_union = new_class(
cls.__name__,
(TaggedUnion, ),
exec_body=lambda ns: ns.update({
"__annotations__": {
sub.__name__: Tagged[sub]
for sub in rec_subclasses(cls) # type: ignore
}
}),
)
return Conversion(
lambda obj: serialization_union(**{obj.__class__.__name__: obj}),
source=cls,
target=serialization_union,
# Conversion must not be inherited because it would lead to infinite
# recursion otherwise
inherited=False,
)
from apischema.conversions import Conversion
@dataclass
class RGB:
red: int
green: int
blue: int
@serializer
@property
def hexa(self) -> str:
return f"#{self.red:02x}{self.green:02x}{self.blue:02x}"
assert serialize(RGB, RGB(0, 0, 0)) == "#000000"
# dynamic conversion used to bypass the registered one
assert serialize(RGB, RGB(0, 0, 0), conversion=identity) == {
"red": 0,
"green": 0,
"blue": 0,
}
# Expended bypass form
assert serialize(RGB,
RGB(0, 0, 0),
conversion=Conversion(identity, source=RGB, target=RGB)) == {
"red": 0,
"green": 0,
"blue": 0
}
PurePath,
PurePosixPath,
PureWindowsPath,
WindowsPath,
)
from typing import Deque, List, TypeVar
from uuid import UUID
from apischema import deserializer, schema, serializer, type_name
from apischema.conversions import Conversion, as_str
T = TypeVar("T")
# =================== bytes =====================
deserializer(Conversion(b64decode, source=str, target=bytes))
@serializer
def to_base64(b: bytes) -> str:
return b64encode(b).decode()
type_name(graphql="Bytes")(bytes)
schema(encoding="base64")(bytes)
# ================ collections ==================
deserializer(Conversion(deque, source=List[T], target=Deque[T]))
serializer(Conversion(list, source=Deque[T], target=List[T]))
if sys.version_info < (3, 7):
def __init_subclass__(cls):
# Deserializers stack directly as a Union
deserializer(Conversion(identity, source=cls, target=Arg))
def handle_enum(tp: AnyType) -> Optional[AnyConversion]:
if is_type(tp) and issubclass(tp, Enum):
return Conversion(identity, source=Any, target=tp)
return default_deserialization(tp)
from base64 import b64decode from apischema import deserialize, deserializer from apischema.conversions import Conversion deserializer(Conversion(b64decode, source=str, target=bytes)) # Roughly equivalent to: # def decode_bytes(source: str) -> bytes: # return b64decode(source) # but saving a function call assert deserialize(bytes, "Zm9v") == b"foo"