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- # SPDX-License-Identifier: MIT
- """
- Commonly useful validators.
- """
- import operator
- import re
- from contextlib import contextmanager
- from re import Pattern
- from ._config import get_run_validators, set_run_validators
- from ._make import _AndValidator, and_, attrib, attrs
- from .converters import default_if_none
- from .exceptions import NotCallableError
- __all__ = [
- "and_",
- "deep_iterable",
- "deep_mapping",
- "disabled",
- "ge",
- "get_disabled",
- "gt",
- "in_",
- "instance_of",
- "is_callable",
- "le",
- "lt",
- "matches_re",
- "max_len",
- "min_len",
- "not_",
- "optional",
- "or_",
- "set_disabled",
- ]
- def set_disabled(disabled):
- """
- Globally disable or enable running validators.
- By default, they are run.
- Args:
- disabled (bool): If `True`, disable running all validators.
- .. warning::
- This function is not thread-safe!
- .. versionadded:: 21.3.0
- """
- set_run_validators(not disabled)
- def get_disabled():
- """
- Return a bool indicating whether validators are currently disabled or not.
- Returns:
- bool:`True` if validators are currently disabled.
- .. versionadded:: 21.3.0
- """
- return not get_run_validators()
- @contextmanager
- def disabled():
- """
- Context manager that disables running validators within its context.
- .. warning::
- This context manager is not thread-safe!
- .. versionadded:: 21.3.0
- .. versionchanged:: 26.1.0 The contextmanager is nestable.
- """
- prev = get_run_validators()
- set_run_validators(False)
- try:
- yield
- finally:
- set_run_validators(prev)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _InstanceOfValidator:
- type = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not isinstance(value, self.type):
- msg = f"'{attr.name}' must be {self.type!r} (got {value!r} that is a {value.__class__!r})."
- raise TypeError(
- msg,
- attr,
- self.type,
- value,
- )
- def __repr__(self):
- return f"<instance_of validator for type {self.type!r}>"
- def instance_of(type):
- """
- A validator that raises a `TypeError` if the initializer is called with a
- wrong type for this particular attribute (checks are performed using
- `isinstance` therefore it's also valid to pass a tuple of types).
- Args:
- type (type | tuple[type]): The type to check for.
- Raises:
- TypeError:
- With a human readable error message, the attribute (of type
- `attrs.Attribute`), the expected type, and the value it got.
- """
- return _InstanceOfValidator(type)
- @attrs(repr=False, frozen=True, slots=True)
- class _MatchesReValidator:
- pattern = attrib()
- match_func = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not self.match_func(value):
- msg = f"'{attr.name}' must match regex {self.pattern.pattern!r} ({value!r} doesn't)"
- raise ValueError(
- msg,
- attr,
- self.pattern,
- value,
- )
- def __repr__(self):
- return f"<matches_re validator for pattern {self.pattern!r}>"
- def matches_re(regex, flags=0, func=None):
- r"""
- A validator that raises `ValueError` if the initializer is called with a
- string that doesn't match *regex*.
- Args:
- regex (str, re.Pattern):
- A regex string or precompiled pattern to match against
- flags (int):
- Flags that will be passed to the underlying re function (default 0)
- func (typing.Callable):
- Which underlying `re` function to call. Valid options are
- `re.fullmatch`, `re.search`, and `re.match`; the default `None`
- means `re.fullmatch`. For performance reasons, the pattern is
- always precompiled using `re.compile`.
- .. versionadded:: 19.2.0
- .. versionchanged:: 21.3.0 *regex* can be a pre-compiled pattern.
- """
- valid_funcs = (re.fullmatch, None, re.search, re.match)
- if func not in valid_funcs:
- msg = "'func' must be one of {}.".format(
- ", ".join(
- sorted((e and e.__name__) or "None" for e in set(valid_funcs))
- )
- )
- raise ValueError(msg)
- if isinstance(regex, Pattern):
- if flags:
- msg = "'flags' can only be used with a string pattern; pass flags to re.compile() instead"
- raise TypeError(msg)
- pattern = regex
- else:
- pattern = re.compile(regex, flags)
- if func is re.match:
- match_func = pattern.match
- elif func is re.search:
- match_func = pattern.search
- else:
- match_func = pattern.fullmatch
- return _MatchesReValidator(pattern, match_func)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _OptionalValidator:
- validator = attrib()
- def __call__(self, inst, attr, value):
- if value is None:
- return
- self.validator(inst, attr, value)
- def __repr__(self):
- return f"<optional validator for {self.validator!r} or None>"
- def optional(validator):
- """
- A validator that makes an attribute optional. An optional attribute is one
- which can be set to `None` in addition to satisfying the requirements of
- the sub-validator.
- Args:
- validator
- (typing.Callable | tuple[typing.Callable] | list[typing.Callable]):
- A validator (or validators) that is used for non-`None` values.
- .. versionadded:: 15.1.0
- .. versionchanged:: 17.1.0 *validator* can be a list of validators.
- .. versionchanged:: 23.1.0 *validator* can also be a tuple of validators.
- """
- if isinstance(validator, (list, tuple)):
- return _OptionalValidator(_AndValidator(validator))
- return _OptionalValidator(validator)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _InValidator:
- options = attrib()
- _original_options = attrib(hash=False)
- def __call__(self, inst, attr, value):
- try:
- in_options = value in self.options
- except TypeError: # e.g. `1 in "abc"`
- in_options = False
- if not in_options:
- msg = f"'{attr.name}' must be in {self._original_options!r} (got {value!r})"
- raise ValueError(
- msg,
- attr,
- self._original_options,
- value,
- )
- def __repr__(self):
- return f"<in_ validator with options {self._original_options!r}>"
- def in_(options):
- """
- A validator that raises a `ValueError` if the initializer is called with a
- value that does not belong in the *options* provided.
- The check is performed using ``value in options``, so *options* has to
- support that operation.
- To keep the validator hashable, dicts, lists, and sets are transparently
- transformed into a `tuple`.
- Args:
- options: Allowed options.
- Raises:
- ValueError:
- With a human readable error message, the attribute (of type
- `attrs.Attribute`), the expected options, and the value it got.
- .. versionadded:: 17.1.0
- .. versionchanged:: 22.1.0
- The ValueError was incomplete until now and only contained the human
- readable error message. Now it contains all the information that has
- been promised since 17.1.0.
- .. versionchanged:: 24.1.0
- *options* that are a list, dict, or a set are now transformed into a
- tuple to keep the validator hashable.
- """
- repr_options = options
- if isinstance(options, (list, dict, set)):
- options = tuple(options)
- return _InValidator(options, repr_options)
- @attrs(repr=False, slots=False, unsafe_hash=True)
- class _IsCallableValidator:
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not callable(value):
- message = (
- "'{name}' must be callable "
- "(got {value!r} that is a {actual!r})."
- )
- raise NotCallableError(
- msg=message.format(
- name=attr.name, value=value, actual=value.__class__
- ),
- value=value,
- )
- def __repr__(self):
- return "<is_callable validator>"
- def is_callable():
- """
- A validator that raises a `attrs.exceptions.NotCallableError` if the
- initializer is called with a value for this particular attribute that is
- not callable.
- .. versionadded:: 19.1.0
- Raises:
- attrs.exceptions.NotCallableError:
- With a human readable error message containing the attribute
- (`attrs.Attribute`) name, and the value it got.
- """
- return _IsCallableValidator()
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _DeepIterable:
- member_validator = attrib(validator=is_callable())
- iterable_validator = attrib(
- default=None, validator=optional(is_callable())
- )
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if self.iterable_validator is not None:
- self.iterable_validator(inst, attr, value)
- for member in value:
- self.member_validator(inst, attr, member)
- def __repr__(self):
- iterable_identifier = (
- ""
- if self.iterable_validator is None
- else f" {self.iterable_validator!r}"
- )
- return (
- f"<deep_iterable validator for{iterable_identifier}"
- f" iterables of {self.member_validator!r}>"
- )
- def deep_iterable(member_validator, iterable_validator=None):
- """
- A validator that performs deep validation of an iterable.
- Args:
- member_validator: Validator(s) to apply to iterable members.
- iterable_validator:
- Validator(s) to apply to iterable itself (optional).
- Raises
- TypeError: if any sub-validators fail
- .. versionadded:: 19.1.0
- .. versionchanged:: 25.4.0
- *member_validator* and *iterable_validator* can now be a list or tuple
- of validators.
- """
- if isinstance(member_validator, (list, tuple)):
- member_validator = and_(*member_validator)
- if isinstance(iterable_validator, (list, tuple)):
- iterable_validator = and_(*iterable_validator)
- return _DeepIterable(member_validator, iterable_validator)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _DeepMapping:
- key_validator = attrib(validator=optional(is_callable()))
- value_validator = attrib(validator=optional(is_callable()))
- mapping_validator = attrib(validator=optional(is_callable()))
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if self.mapping_validator is not None:
- self.mapping_validator(inst, attr, value)
- for key in value:
- if self.key_validator is not None:
- self.key_validator(inst, attr, key)
- if self.value_validator is not None:
- self.value_validator(inst, attr, value[key])
- def __repr__(self):
- return f"<deep_mapping validator for objects mapping {self.key_validator!r} to {self.value_validator!r}>"
- def deep_mapping(
- key_validator=None, value_validator=None, mapping_validator=None
- ):
- """
- A validator that performs deep validation of a dictionary.
- All validators are optional, but at least one of *key_validator* or
- *value_validator* must be provided.
- Args:
- key_validator: Validator(s) to apply to dictionary keys.
- value_validator: Validator(s) to apply to dictionary values.
- mapping_validator:
- Validator(s) to apply to top-level mapping attribute.
- .. versionadded:: 19.1.0
- .. versionchanged:: 25.4.0
- *key_validator* and *value_validator* are now optional, but at least one
- of them must be provided.
- .. versionchanged:: 25.4.0
- *key_validator*, *value_validator*, and *mapping_validator* can now be a
- list or tuple of validators.
- Raises:
- TypeError: If any sub-validator fails on validation.
- ValueError:
- If neither *key_validator* nor *value_validator* is provided on
- instantiation.
- """
- if key_validator is None and value_validator is None:
- msg = (
- "At least one of key_validator or value_validator must be provided"
- )
- raise ValueError(msg)
- if isinstance(key_validator, (list, tuple)):
- key_validator = and_(*key_validator)
- if isinstance(value_validator, (list, tuple)):
- value_validator = and_(*value_validator)
- if isinstance(mapping_validator, (list, tuple)):
- mapping_validator = and_(*mapping_validator)
- return _DeepMapping(key_validator, value_validator, mapping_validator)
- @attrs(repr=False, frozen=True, slots=True)
- class _NumberValidator:
- bound = attrib()
- compare_op = attrib()
- compare_func = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not self.compare_func(value, self.bound):
- msg = f"'{attr.name}' must be {self.compare_op} {self.bound}: {value}"
- raise ValueError(msg)
- def __repr__(self):
- return f"<Validator for x {self.compare_op} {self.bound}>"
- def lt(val):
- """
- A validator that raises `ValueError` if the initializer is called with a
- number larger or equal to *val*.
- The validator uses `operator.lt` to compare the values.
- Args:
- val: Exclusive upper bound for values.
- .. versionadded:: 21.3.0
- """
- return _NumberValidator(val, "<", operator.lt)
- def le(val):
- """
- A validator that raises `ValueError` if the initializer is called with a
- number greater than *val*.
- The validator uses `operator.le` to compare the values.
- Args:
- val: Inclusive upper bound for values.
- .. versionadded:: 21.3.0
- """
- return _NumberValidator(val, "<=", operator.le)
- def ge(val):
- """
- A validator that raises `ValueError` if the initializer is called with a
- number smaller than *val*.
- The validator uses `operator.ge` to compare the values.
- Args:
- val: Inclusive lower bound for values
- .. versionadded:: 21.3.0
- """
- return _NumberValidator(val, ">=", operator.ge)
- def gt(val):
- """
- A validator that raises `ValueError` if the initializer is called with a
- number smaller or equal to *val*.
- The validator uses `operator.gt` to compare the values.
- Args:
- val: Exclusive lower bound for values
- .. versionadded:: 21.3.0
- """
- return _NumberValidator(val, ">", operator.gt)
- @attrs(repr=False, frozen=True, slots=True)
- class _MaxLengthValidator:
- max_length = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if len(value) > self.max_length:
- msg = f"Length of '{attr.name}' must be <= {self.max_length}: {len(value)}"
- raise ValueError(msg)
- def __repr__(self):
- return f"<max_len validator for {self.max_length}>"
- def max_len(length):
- """
- A validator that raises `ValueError` if the initializer is called
- with a string or iterable that is longer than *length*.
- Args:
- length (int): Maximum length of the string or iterable
- .. versionadded:: 21.3.0
- """
- return _MaxLengthValidator(length)
- @attrs(repr=False, frozen=True, slots=True)
- class _MinLengthValidator:
- min_length = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if len(value) < self.min_length:
- msg = f"Length of '{attr.name}' must be >= {self.min_length}: {len(value)}"
- raise ValueError(msg)
- def __repr__(self):
- return f"<min_len validator for {self.min_length}>"
- def min_len(length):
- """
- A validator that raises `ValueError` if the initializer is called
- with a string or iterable that is shorter than *length*.
- Args:
- length (int): Minimum length of the string or iterable
- .. versionadded:: 22.1.0
- """
- return _MinLengthValidator(length)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _SubclassOfValidator:
- type = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not issubclass(value, self.type):
- msg = f"'{attr.name}' must be a subclass of {self.type!r} (got {value!r})."
- raise TypeError(
- msg,
- attr,
- self.type,
- value,
- )
- def __repr__(self):
- return f"<subclass_of validator for type {self.type!r}>"
- def _subclass_of(type):
- """
- A validator that raises a `TypeError` if the initializer is called with a
- wrong type for this particular attribute (checks are performed using
- `issubclass` therefore it's also valid to pass a tuple of types).
- Args:
- type (type | tuple[type, ...]): The type(s) to check for.
- Raises:
- TypeError:
- With a human readable error message, the attribute (of type
- `attrs.Attribute`), the expected type, and the value it got.
- """
- return _SubclassOfValidator(type)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _NotValidator:
- validator = attrib()
- msg = attrib(
- converter=default_if_none(
- "not_ validator child '{validator!r}' "
- "did not raise a captured error"
- )
- )
- exc_types = attrib(
- validator=deep_iterable(
- member_validator=_subclass_of(Exception),
- iterable_validator=instance_of(tuple),
- ),
- )
- def __call__(self, inst, attr, value):
- try:
- self.validator(inst, attr, value)
- except self.exc_types:
- pass # suppress error to invert validity
- else:
- raise ValueError(
- self.msg.format(
- validator=self.validator,
- exc_types=self.exc_types,
- ),
- attr,
- self.validator,
- value,
- self.exc_types,
- )
- def __repr__(self):
- return f"<not_ validator wrapping {self.validator!r}, capturing {self.exc_types!r}>"
- def not_(validator, *, msg=None, exc_types=(ValueError, TypeError)):
- """
- A validator that wraps and logically 'inverts' the validator passed to it.
- It will raise a `ValueError` if the provided validator *doesn't* raise a
- `ValueError` or `TypeError` (by default), and will suppress the exception
- if the provided validator *does*.
- Intended to be used with existing validators to compose logic without
- needing to create inverted variants, for example, ``not_(in_(...))``.
- Args:
- validator: A validator to be logically inverted.
- msg (str):
- Message to raise if validator fails. Formatted with keys
- ``exc_types`` and ``validator``.
- exc_types (tuple[type, ...]):
- Exception type(s) to capture. Other types raised by child
- validators will not be intercepted and pass through.
- Raises:
- ValueError:
- With a human readable error message, the attribute (of type
- `attrs.Attribute`), the validator that failed to raise an
- exception, the value it got, and the expected exception types.
- .. versionadded:: 22.2.0
- """
- try:
- exc_types = tuple(exc_types)
- except TypeError:
- exc_types = (exc_types,)
- return _NotValidator(validator, msg, exc_types)
- @attrs(repr=False, slots=True, unsafe_hash=True)
- class _OrValidator:
- validators = attrib()
- def __call__(self, inst, attr, value):
- for v in self.validators:
- try:
- v(inst, attr, value)
- except Exception: # noqa: BLE001, PERF203, S112
- continue
- else:
- return
- msg = f"None of {self.validators!r} satisfied for value {value!r}"
- raise ValueError(msg)
- def __repr__(self):
- return f"<or validator wrapping {self.validators!r}>"
- def or_(*validators):
- """
- A validator that composes multiple validators into one.
- When called on a value, it runs all wrapped validators until one of them is
- satisfied.
- Args:
- validators (~collections.abc.Iterable[typing.Callable]):
- Arbitrary number of validators.
- Raises:
- ValueError:
- If no validator is satisfied. Raised with a human-readable error
- message listing all the wrapped validators and the value that
- failed all of them.
- .. versionadded:: 24.1.0
- """
- vals = []
- for v in validators:
- vals.extend(v.validators if isinstance(v, _OrValidator) else [v])
- return _OrValidator(tuple(vals))
|