def _checked_value(self, instance, value):
# We allow four forms of value:
# 1. An opaque (to us) string address pointing to a value that can be resolved by external
# means.
# 2. A `Resolvable` value that we can lazily resolve and type-check in `__get__`.
# 3. A concrete instance that meets our type constraint.
# 4. A dict when our type constraint has exactly one Serializable subject type - we convert the
# dict into an instance of that type.
if value is None:
return None
if isinstance(value, (six.string_types, Resolvable)):
return value
# Support untyped dicts that we deserialize on-demand here into the required type.
# This feature allows for more brevity in the JSON form (local type inference) and an alternate
# construction style in the python forms.
type_constraint = self._get_type_constraint(instance)
if (isinstance(value, dict) and len(type_constraint.types) == 1 and
Serializable.is_serializable_type(type_constraint.types[0])):
if not value:
# TODO(John Sirois): Is this the right thing to do? Or should an empty serializable_type
# be constructed?
return None # {} -> None.
else:
serializable_type = type_constraint.types[0]
return serializable_type(**value)
if not type_constraint.satisfied_by(value):
raise TypeConstraintError(
'Got {} of type {} for {} attribute of {} but expected {!r}'.
format(value,
type(value).__name__, self._name, instance,
type_constraint))
return value
def _checked_value(self, instance, value):
# We allow five forms of value:
# 0. None.
# 1. An opaque (to us) address pointing to a value that can be resolved by external
# means.
# 2. A `Resolvable` value that we can lazily resolve and type-check in `__get__`.
# 3. A concrete instance that meets our type constraint.
# 4. A dict when our type constraint has exactly one Serializable subject type - we convert the
# dict into an instance of that type.
if value is None:
return None
if isinstance(value, (six.string_types, Address, Resolvable)):
return value
# Support untyped dicts that we deserialize on-demand here into the required type.
# This feature allows for more brevity in the JSON form (local type inference) and an alternate
# construction style in the python forms.
type_constraint = self._get_type_constraint(instance)
if (
isinstance(value, dict)
and len(type_constraint.types) == 1
and Serializable.is_serializable_type(type_constraint.types[0])
):
if not value:
# TODO(John Sirois): Is this the right thing to do? Or should an empty serializable_type
# be constructed?
return None # {} -> None.
else:
serializable_type = type_constraint.types[0]
return serializable_type(**value)
if not type_constraint.satisfied_by(value):
raise TypeConstraintError(
"Got {} of type {} for {} attribute of {} but expected {!r}".format(
value, type(value).__name__, self._name, instance, type_constraint
)
)
return value
def __init__(self, type_alias, object_type): self._type_alias = type_alias self._object_type = object_type self._serializable = Serializable.is_serializable_type(self._object_type)
def __init__(self, type_alias, object_type):
self._type_alias = type_alias
self._object_type = object_type
self._serializable = Serializable.is_serializable_type(
self._object_type)
