import collections
import typing
from ._error import AttributeTypeError, BadTypeError, TupleError, UnionError
[docs]def type_validator(empty_ok=True):
"""
Validates the attributes using the type argument specified. If the
type argument is not present, the attribute is considered valid.
:param empty_ok: Boolean flag that indicates if the field can be empty
in case of a collection or None for builtin types.
"""
def _validator(instance, attribute, field):
if not empty_ok and not field:
raise ValueError("Expected a non-empty attribute")
_validate_elements(attribute, field, attribute.type)
return _validator
def _validate_elements(attribute, value, expected_type):
base_type = (
expected_type.__origin__
if hasattr(expected_type, "__origin__")
and expected_type.__origin__ is not None
else expected_type
)
if base_type is None:
return
if base_type != typing.Union and not isinstance(value, base_type):
raise AttributeTypeError(value, attribute)
if base_type in {set, list, typing.List, typing.Set}:
_handle_set_or_list(attribute, value, expected_type)
elif base_type in {
dict,
collections.OrderedDict,
collections.defaultdict,
typing.Dict,
typing.DefaultDict,
}:
_handle_dict(attribute, value, expected_type)
elif base_type in {tuple, typing.Tuple}:
_handle_tuple(attribute, value, expected_type)
elif base_type == typing.Union:
_handle_union(attribute, value, expected_type)
def _handle_set_or_list(attribute, container, expected_type):
element_type, = expected_type.__args__
for element in container:
try:
_validate_elements(attribute, element, element_type)
except BadTypeError as error:
error.add_container(container)
raise error
def _handle_dict(attribute, container, expected_type):
key_type, value_type = expected_type.__args__
for key in container:
try:
_validate_elements(attribute, key, key_type)
_validate_elements(attribute, container[key], value_type)
except BadTypeError as error:
error.add_container(container)
raise error
def _handle_tuple(attribute, container, expected_type):
tuple_types = expected_type.__args__
if len(container) != len(tuple_types):
raise TupleError(container, attribute.type, tuple_types)
for element, expected_type in zip(container, tuple_types):
try:
_validate_elements(attribute, element, expected_type)
except BadTypeError as error:
error.add_container(container)
raise error
def _handle_union(attribute, value, expected_type):
union_has_none_type = any(
elem is None.__class__ for elem in expected_type.__args__
)
if value is None and union_has_none_type:
return
for arg in expected_type.__args__:
try:
_validate_elements(attribute, value, arg)
return
except ValueError:
pass
raise UnionError(value, attribute.name, expected_type)
# -----------------------------------------------------------------------------
# Copyright 2019 Bloomberg Finance L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ----------------------------- END-OF-FILE -----------------------------------