Mini Shell
# 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
"""
set_run_validators(False)
try:
yield
finally:
set_run_validators(True)
@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 to apply to iterable members.
iterable_validator:
Validator to apply to iterable itself (optional).
Raises
TypeError: if any sub-validators fail
.. versionadded:: 19.1.0
"""
if isinstance(member_validator, (list, tuple)):
member_validator = and_(*member_validator)
return _DeepIterable(member_validator, iterable_validator)
@attrs(repr=False, slots=True, unsafe_hash=True)
class _DeepMapping:
key_validator = attrib(validator=is_callable())
value_validator = attrib(validator=is_callable())
mapping_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.mapping_validator is not None:
self.mapping_validator(inst, attr, value)
for key in value:
self.key_validator(inst, attr, key)
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, value_validator, mapping_validator=None):
"""
A validator that performs deep validation of a dictionary.
Args:
key_validator: Validator to apply to dictionary keys.
value_validator: Validator to apply to dictionary values.
mapping_validator:
Validator to apply to top-level mapping attribute (optional).
.. versionadded:: 19.1.0
Raises:
TypeError: if any sub-validators fail
"""
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.ge` 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))
Zerion Mini Shell 1.0