def _get_fields_uncached():
dataclass_bases = [
klass for klass in cls.__bases__ if is_dataclass(klass) and issubclass(klass, JsonSchemaMixin)
]
base_fields_types = set()
for base in dataclass_bases:
base_fields_types |= {(f.name, f.type) for f in fields(base)}
mapped_fields = []
type_hints = get_type_hints(cls)
for f in fields(cls):
# Skip internal fields
if f.name.startswith("__") or (not base_fields and (f.name, f.type) in base_fields_types):
continue
# Note fields() doesn't resolve forward refs
f.type = type_hints[f.name]
mapped_fields.append(JsonSchemaField(f, cls.field_mapping().get(f.name, f.name)))
if cls.__serialise_properties:
include_properties = None
if isinstance(cls.__serialise_properties, tuple):
include_properties = set(cls.__serialise_properties)
members = inspect.getmembers(cls, inspect.isdatadescriptor)
for name, member in members:
if name != "__weakref__" and (include_properties is None or name in include_properties):
f = Field(MISSING, None, None, None, None, None, None)
f.name = name
f.type = member.fget.__annotations__['return']
mapped_fields.append(JsonSchemaField(f, name, is_property=True))
return mapped_fields
def _serialize_field(field_: Field):
"""
:param field_:
:return:
"""
if isinstance(field_, Base):
return field_.id_
if isinstance(field_, datetime):
return field_.strftime("%Y-%m-%d %H:%M:%S")
if isinstance(field_, date):
return field_.strftime("%Y-%m-%d")
return field_
def _serialize_field(field_: Field):
"""
:param field_:
:return:
"""
if issubclass(field_.__class__, Entity):
return field_.id_
if isinstance(field_, datetime):
return field_.strftime("%Y-%m-%d %H:%M:%S")
if isinstance(field_, date):
return field_.strftime("%Y-%m-%d")
return field_
def get_default(field: Field, schema: Schema[T]) -> Any:
if not schema.omit_default:
return MISSING
# type ignore because of https://github.com/python/mypy/issues/6910
if field.default_factory != MISSING: # type: ignore
return field.default_factory() # type: ignore
return field.default
def _get_field_meta(cls, field: Field, schema_type: SchemaType) -> Tuple[FieldMeta, bool]:
required = True
field_meta = FieldMeta(schema_type=schema_type)
default_value = MISSING
if field.default is not MISSING:
# In case of default value given
default_value = field.default
elif field.default_factory is not MISSING and field.default_factory is not None: # type: ignore
# In case of a default factory given, we call it
default_value = field.default_factory() # type: ignore
if default_value is not MISSING:
field_meta.default = cls._encode_field(field.type, default_value, omit_none=False)
required = False
if field.metadata is not None:
if "examples" in field.metadata:
field_meta.examples = [
cls._encode_field(field.type, example, omit_none=False) for example in field.metadata["examples"]
]
if "extensions" in field.metadata:
field_meta.extensions = field.metadata["extensions"]
if "description" in field.metadata:
field_meta.description = field.metadata["description"]
if "title" in field.metadata:
field_meta.title = field.metadata["title"]
if schema_type == SchemaType.OPENAPI_3:
field_meta.read_only = field.metadata.get("read_only")
if field_meta.read_only and default_value is MISSING:
warnings.warn(f"Read-only fields should have a default value")
field_meta.write_only = field.metadata.get("write_only")
return field_meta, required
def _get_field_meta(cls, field: Field,
schema_type: SchemaType) -> Tuple[FieldMeta, bool]:
required = True
field_meta = FieldMeta()
default_value = None
if field.default is not MISSING and field.default is not None:
# In case of default value given
default_value = field.default
elif field.default_factory is not MISSING and field.default_factory is not None: # type: ignore
# In case of a default factory given, we call it
default_value = field.default_factory() # type: ignore
if default_value is not None:
field_meta.default = cls._encode_field(field.type,
default_value,
omit_none=False)
required = False
if field.metadata is not None:
if "description" in field.metadata:
field_meta.description = field.metadata["description"]
if schema_type == SchemaType.OPENAPI_3:
field_meta.read_only = field.metadata.get("read_only")
if field_meta.read_only and default_value is None:
raise ValueError(
f"Read-only fields must have a default value")
field_meta.write_only = field.metadata.get("write_only")
return field_meta, required
def get_dataclass_default(field: Field, omit_default: Optional[bool]) -> Any:
if not omit_default:
return MISSING
# type ignore because of https://github.com/python/mypy/issues/6910
if field.default_factory != MISSING: # type: ignore
return field.default_factory() # type: ignore
return field.default
def name(name: str, field: Field = None):
if field is None:
field = fld()
meta = dict(getattr(field, "metadata", _EMPTY_METADATA))
meta[Mods.name] = {"from": name}
field.metadata = types.MappingProxyType(meta)
return field
def get_default_value_for_field(field: Field) -> Any:
if field.default != MISSING:
return field.default
elif field.default_factory != MISSING: # type: ignore
return field.default_factory() # type: ignore
elif is_optional(field.type):
return None
raise DefaultValueNotFoundError()
def _get_default_value_for_field(field: Field) -> Any:
if field.default != MISSING:
return field.default
elif field.default_factory != MISSING:
return field.default_factory()
elif _is_optional(field.type):
return None
else:
raise MissingValueError(field)
def _get_dataclass_field_default(field: Field) -> Any:
if field.default_factory is not MISSING:
# pyre-fixme[29]: `Union[dataclasses._MISSING_TYPE,
# dataclasses._DefaultFactory[typing.Any]]` is not a function.
return field.default_factory()
elif field.default is not MISSING:
return field.default
else:
return None
def _load_enum(obj, f: Field, prefix: str) -> None:
enum_annotations = f.type.__dict__.get('__annotations__', {})
name = f'{prefix.upper()}_{f.name.upper()}'
for n, nested_type in enum_annotations.items():
try:
setattr(obj, f.name, f.type(nested_type(os.environ[name])))
return
except ValueError:
continue
def deserialize_field(
field: dataclasses.Field,
serialized_value: Union[dict, PrimitiveType,
CollectionOfPrimitiveType]):
if issubclass(field.type, Serializable):
return field.type.from_dict(dct=serialized_value,
streets_map=streets_map)
if issubclass(field.type, Junction):
assert streets_map is not None
return streets_map[int(serialized_value)]
if issubclass(field.type, (list, tuple)):
assert all(
isinstance(val, (str, int, float))
for val in serialized_value)
return field.type(serialized_value)
assert any(
issubclass(field.type, primitive_type)
for primitive_type in (str, int, float))
return field.type(serialized_value)
def deserialize_field(field: dataclasses.Field, serialized_value: str):
if issubclass(field.type, Serializable):
return field.type.deserialize(serialized=serialized_value,
streets_map=streets_map)
if issubclass(field.type, Junction):
assert streets_map is not None
return streets_map[int(serialized_value)]
assert any(
issubclass(field.type, primitive_type)
for primitive_type in (str, int, float))
return field.type(serialized_value)
def _convert_dataclass_field(value, field: dataclasses.Field):
if value is not dataclasses.MISSING:
return convert(value, field.type)
if field.default is not dataclasses.MISSING:
return field.default
if field.default_factory is not dataclasses.MISSING:
return field.default_factory()
elif is_optional(field.type):
return None
else:
raise MissingException
def _get_field_default(field: dataclasses.Field):
"""
Return a marshmallow default value given a dataclass default value
>>> _get_field_default(dataclasses.field())
<marshmallow.missing>
"""
if field.default_factory is not dataclasses.MISSING:
return field.default_factory()
elif field.default is dataclasses.MISSING:
return marshmallow.missing
return field.default
def field(*, field=None, callback=None, default=MISSING, default_factory=MISSING, init=True, repr=True,
hash=None, compare=True, metadata=None):
if default is not MISSING and default_factory is not MISSING:
raise ValueError('cannot specify both default and default_factory')
if field is not None or callback is not None:
if callback is not None:
if field is not None:
raise ValueError('cannot specify both field and callback')
if not callable(callback):
raise ValueError('callback must be callable')
return RowField(field, callback, default, default_factory, init, repr, hash, compare, metadata)
else:
return Field(default, default_factory, init, repr, hash, compare, metadata)
def _default_value(x: Field):
"""Return the default value of the input Field.
Args:
x (Field): input Field.
Returns:
object: default value of the input Field.
"""
if x.default not in (MISSING, _MISSING):
return x.default
if x.default_factory not in (MISSING, _MISSING):
return x.default_factory()
return x.default
def auto_conversion(obj, field: dataclasses.Field):
""" Tries to convert the field to the right type
Raises a TypeError if conversion fails.
obj -- The obj the field belongs to
field -- The field to check
"""
field_val = getattr(obj, field.name)
if not field_val is None and not isinstance(field_val, field.type):
try:
setattr(obj, field.name, field.type(field_val))
except TypeError as error:
error_handling_auto_conversion(obj, field, error)
def _add_type_list(group: argparse._ArgumentGroup, field: dataclasses.Field,
name: str):
group.add_argument(
f"--{name}_{field.name}",
type=typing.get_args(field.type)[0],
default=None
if field.default_factory is dataclasses.MISSING # type: ignore
else field.default_factory(), # type: ignore
required=field.default_factory is dataclasses.MISSING, # type: ignore
choices=field.metadata.get( # type: ignore
Options.POSSIBLE_VALUES, Options.POSSIBLE_VALUES.value),
help=field.metadata.get(Options.HELP_TEXT,
Options.HELP_TEXT.value), # type: ignore
nargs="*",
)
def _get_value_for_field(field: Field, data: Data, config: Config) -> Any:
try:
if field.name in config.prefixed:
return _extract_nested_dict_for_prefix(config.prefixed[field.name],
data)
elif field.name in config.flattened:
return _extract_flattened_fields(field, data, config.remap)
else:
key_name = config.remap.get(field.name, field.name)
return data[key_name]
except KeyError:
if _is_optional(field.type):
return None
elif field.default != MISSING:
return field.default
elif field.default_factory != MISSING:
return field.default_factory()
else:
raise MissingValueError(field)
def _get_default(catch_all_field: Field) -> Any:
# access to the default factory currently causes
# a false-positive mypy error (16. Dec 2019):
# https://github.com/python/mypy/issues/6910
# noinspection PyProtectedMember
has_default = not isinstance(catch_all_field.default,
dataclasses._MISSING_TYPE)
# noinspection PyProtectedMember
has_default_factory = not isinstance(catch_all_field.default_factory,
# type: ignore
dataclasses._MISSING_TYPE)
default_value = _CatchAllUndefinedParameters._SentinelNoDefault
if has_default:
default_value = catch_all_field.default
elif has_default_factory:
# This might be unwanted if the default factory constructs
# something expensive,
# because we have to construct it again just for this test
default_value = catch_all_field.default_factory() # type: ignore
return default_value
def _get_field_meta(cls, field: Field,
schema_type: SchemaType) -> Tuple[FieldMeta, bool]:
required = True
field_meta = FieldMeta()
default_value = None
if field.default is not MISSING and field.default is not None:
# In case of default value given
default_value = field.default
elif field.default_factory is not MISSING and field.default_factory is not None: # type: ignore
# In case of a default factory given, we call it
default_value = field.default_factory() # type: ignore
if default_value is not None:
field_meta.default = cls._encode_field(field.type,
default_value,
omit_none=False)
required = False
if field.metadata is not None:
if "description" in field.metadata:
field_meta.description = field.metadata["description"]
return field_meta, required
def _parse_dataclass_field(parser: ArgumentParser,
field: dataclasses.Field):
field_name = f"--{field.name}"
kwargs = field.metadata.copy()
# field.metadata is not used at all by Data Classes,
# it is provided as a third-party extension mechanism.
if isinstance(field.type, str):
raise RuntimeError(
"Unresolved type detected, which should have been done with the help of "
"`typing.get_type_hints` method by default")
origin_type = getattr(field.type, "__origin__", field.type)
if origin_type is Union:
if len(field.type.__args__) != 2 or type(
None) not in field.type.__args__:
raise ValueError(
"Only `Union[X, NoneType]` (i.e., `Optional[X]`) is allowed for `Union`"
)
if bool not in field.type.__args__:
# filter `NoneType` in Union (except for `Union[bool, NoneType]`)
field.type = (field.type.__args__[0] if isinstance(
None, field.type.__args__[1]) else field.type.__args__[1])
origin_type = getattr(field.type, "__origin__", field.type)
# A variable to store kwargs for a boolean field, if needed
# so that we can init a `no_*` complement argument (see below)
bool_kwargs = {}
if isinstance(field.type, type) and issubclass(field.type, Enum):
kwargs["choices"] = [x.value for x in field.type]
kwargs["type"] = type(kwargs["choices"][0])
if field.default is not dataclasses.MISSING:
kwargs["default"] = field.default
else:
kwargs["required"] = True
elif field.type is bool or field.type is Optional[bool]:
# Copy the currect kwargs to use to instantiate a `no_*` complement argument below.
# We do not initialize it here because the `no_*` alternative must be instantiated after the real argument
bool_kwargs = copy(kwargs)
# Hack because type=bool in argparse does not behave as we want.
kwargs["type"] = string_to_bool
if field.type is bool or (field.default is not None
and field.default
is not dataclasses.MISSING):
# Default value is False if we have no default when of type bool.
default = False if field.default is dataclasses.MISSING else field.default
# This is the value that will get picked if we don't include --field_name in any way
kwargs["default"] = default
# This tells argparse we accept 0 or 1 value after --field_name
kwargs["nargs"] = "?"
# This is the value that will get picked if we do --field_name (without value)
kwargs["const"] = True
elif isclass(origin_type) and issubclass(origin_type, list):
kwargs["type"] = field.type.__args__[0]
kwargs["nargs"] = "+"
if field.default_factory is not dataclasses.MISSING:
kwargs["default"] = field.default_factory()
elif field.default is dataclasses.MISSING:
kwargs["required"] = True
else:
kwargs["type"] = field.type
if field.default is not dataclasses.MISSING:
kwargs["default"] = field.default
elif field.default_factory is not dataclasses.MISSING:
kwargs["default"] = field.default_factory()
else:
kwargs["required"] = True
parser.add_argument(field_name, **kwargs)
# Add a complement `no_*` argument for a boolean field AFTER the initial field has already been added.
# Order is important for arguments with the same destination!
# We use a copy of earlier kwargs because the original kwargs have changed a lot before reaching down
# here and we do not need those changes/additional keys.
if field.default is True and (field.type is bool
or field.type is Optional[bool]):
bool_kwargs["default"] = False
parser.add_argument(f"--no_{field.name}",
action="store_false",
dest=field.name,
**bool_kwargs)
def default_field_value(f: Field) -> Any:
if callable(f.default_factory): # type: ignore
return f.default_factory() # type: ignore
else:
return f.default
from dataclasses import dataclass,Field
@dataclass
class Employee:
name: str
age: int
gender: str
if __name__ == '__main__':
e1 = Employee('Sasi',30,'M')
e2 = Employee('Ramu',35,'M')
print(e1.__dataclass_fields__)
my_field = Field('city',str)
print(my_field)
def get_default(field: Field) -> Any:
if field.default_factory is not MISSING:
value = field.default_factory()
else:
value = field.default
return value if value is not MISSING else None
def get_dataclass_default(field: Field) -> Any:
# type ignore because of https://github.com/python/mypy/issues/6910
if field.default_factory != MISSING: # type: ignore
return field.default_factory() # type: ignore
return field.default
def has_default(self, field: dataclasses.Field) -> FieldDefault:
if field.default != dataclasses.MISSING:
return FieldDefault(True, field.default)
if field.default_factory != dataclasses.MISSING:
return FieldDefault(True, field.default_factory())
return FieldDefault()
class President():
first_name: Field(str)
last_name: str
birthdate: date
