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- # SPDX-License-Identifier: MIT
- """
- Commonly useful validators.
- """
- from __future__ import absolute_import, division, print_function
- import operator
- import re
- from contextlib import contextmanager
- from ._config import get_run_validators, set_run_validators
- from ._make import _AndValidator, and_, attrib, attrs
- from .exceptions import NotCallableError
- try:
- Pattern = re.Pattern
- except AttributeError: # Python <3.7 lacks a Pattern type.
- Pattern = type(re.compile(""))
- __all__ = [
- "and_",
- "deep_iterable",
- "deep_mapping",
- "disabled",
- "ge",
- "get_disabled",
- "gt",
- "in_",
- "instance_of",
- "is_callable",
- "le",
- "lt",
- "matches_re",
- "max_len",
- "optional",
- "provides",
- "set_disabled",
- ]
- def set_disabled(disabled):
- """
- Globally disable or enable running validators.
- By default, they are run.
- :param disabled: If ``True``, disable running all validators.
- :type disabled: bool
- .. 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.
- :return: ``True`` if validators are currently disabled.
- :rtype: bool
- .. 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, hash=True)
- class _InstanceOfValidator(object):
- 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):
- raise TypeError(
- "'{name}' must be {type!r} (got {value!r} that is a "
- "{actual!r}).".format(
- name=attr.name,
- type=self.type,
- actual=value.__class__,
- value=value,
- ),
- attr,
- self.type,
- value,
- )
- def __repr__(self):
- return "<instance_of validator for type {type!r}>".format(
- type=self.type
- )
- 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).
- :param type: The type to check for.
- :type type: type or tuple of types
- :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(object):
- 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):
- raise ValueError(
- "'{name}' must match regex {pattern!r}"
- " ({value!r} doesn't)".format(
- name=attr.name, pattern=self.pattern.pattern, value=value
- ),
- attr,
- self.pattern,
- value,
- )
- def __repr__(self):
- return "<matches_re validator for pattern {pattern!r}>".format(
- pattern=self.pattern
- )
- 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*.
- :param regex: a regex string or precompiled pattern to match against
- :param int flags: flags that will be passed to the underlying re function
- (default 0)
- :param callable func: which underlying `re` function to call (options
- are `re.fullmatch`, `re.search`, `re.match`, default
- is ``None`` which means either `re.fullmatch` or an emulation of
- it on Python 2). For performance reasons, they won't be used directly
- but on a pre-`re.compile`\ ed pattern.
- .. versionadded:: 19.2.0
- .. versionchanged:: 21.3.0 *regex* can be a pre-compiled pattern.
- """
- fullmatch = getattr(re, "fullmatch", None)
- valid_funcs = (fullmatch, None, re.search, re.match)
- if func not in valid_funcs:
- raise ValueError(
- "'func' must be one of {}.".format(
- ", ".join(
- sorted(
- e and e.__name__ or "None" for e in set(valid_funcs)
- )
- )
- )
- )
- if isinstance(regex, Pattern):
- if flags:
- raise TypeError(
- "'flags' can only be used with a string pattern; "
- "pass flags to re.compile() instead"
- )
- 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
- elif fullmatch:
- match_func = pattern.fullmatch
- else: # Python 2 fullmatch emulation (https://bugs.python.org/issue16203)
- pattern = re.compile(
- r"(?:{})\Z".format(pattern.pattern), pattern.flags
- )
- match_func = pattern.match
- return _MatchesReValidator(pattern, match_func)
- @attrs(repr=False, slots=True, hash=True)
- class _ProvidesValidator(object):
- interface = attrib()
- def __call__(self, inst, attr, value):
- """
- We use a callable class to be able to change the ``__repr__``.
- """
- if not self.interface.providedBy(value):
- raise TypeError(
- "'{name}' must provide {interface!r} which {value!r} "
- "doesn't.".format(
- name=attr.name, interface=self.interface, value=value
- ),
- attr,
- self.interface,
- value,
- )
- def __repr__(self):
- return "<provides validator for interface {interface!r}>".format(
- interface=self.interface
- )
- def provides(interface):
- """
- A validator that raises a `TypeError` if the initializer is called
- with an object that does not provide the requested *interface* (checks are
- performed using ``interface.providedBy(value)`` (see `zope.interface
- <https://zopeinterface.readthedocs.io/en/latest/>`_).
- :param interface: The interface to check for.
- :type interface: ``zope.interface.Interface``
- :raises TypeError: With a human readable error message, the attribute
- (of type `attrs.Attribute`), the expected interface, and the
- value it got.
- """
- return _ProvidesValidator(interface)
- @attrs(repr=False, slots=True, hash=True)
- class _OptionalValidator(object):
- validator = attrib()
- def __call__(self, inst, attr, value):
- if value is None:
- return
- self.validator(inst, attr, value)
- def __repr__(self):
- return "<optional validator for {what} or None>".format(
- what=repr(self.validator)
- )
- 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.
- :param validator: A validator (or a list of validators) that is used for
- non-``None`` values.
- :type validator: callable or `list` of callables.
- .. versionadded:: 15.1.0
- .. versionchanged:: 17.1.0 *validator* can be a list of validators.
- """
- if isinstance(validator, list):
- return _OptionalValidator(_AndValidator(validator))
- return _OptionalValidator(validator)
- @attrs(repr=False, slots=True, hash=True)
- class _InValidator(object):
- options = attrib()
- 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:
- raise ValueError(
- "'{name}' must be in {options!r} (got {value!r})".format(
- name=attr.name, options=self.options, value=value
- )
- )
- def __repr__(self):
- return "<in_ validator with options {options!r}>".format(
- options=self.options
- )
- 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``.
- :param options: Allowed options.
- :type options: list, tuple, `enum.Enum`, ...
- :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
- """
- return _InValidator(options)
- @attrs(repr=False, slots=False, hash=True)
- class _IsCallableValidator(object):
- 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 `attr.exceptions.NotCallableError` if the
- initializer is called with a value for this particular attribute
- that is not callable.
- .. versionadded:: 19.1.0
- :raises `attr.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, hash=True)
- class _DeepIterable(object):
- 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 " {iterable!r}".format(iterable=self.iterable_validator)
- )
- return (
- "<deep_iterable validator for{iterable_identifier}"
- " iterables of {member!r}>"
- ).format(
- iterable_identifier=iterable_identifier,
- member=self.member_validator,
- )
- def deep_iterable(member_validator, iterable_validator=None):
- """
- A validator that performs deep validation of an iterable.
- :param member_validator: Validator to apply to iterable members
- :param iterable_validator: Validator to apply to iterable itself
- (optional)
- .. versionadded:: 19.1.0
- :raises TypeError: if any sub-validators fail
- """
- return _DeepIterable(member_validator, iterable_validator)
- @attrs(repr=False, slots=True, hash=True)
- class _DeepMapping(object):
- 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 (
- "<deep_mapping validator for objects mapping {key!r} to {value!r}>"
- ).format(key=self.key_validator, value=self.value_validator)
- def deep_mapping(key_validator, value_validator, mapping_validator=None):
- """
- A validator that performs deep validation of a dictionary.
- :param key_validator: Validator to apply to dictionary keys
- :param value_validator: Validator to apply to dictionary values
- :param 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(object):
- 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):
- raise ValueError(
- "'{name}' must be {op} {bound}: {value}".format(
- name=attr.name,
- op=self.compare_op,
- bound=self.bound,
- value=value,
- )
- )
- def __repr__(self):
- return "<Validator for x {op} {bound}>".format(
- op=self.compare_op, bound=self.bound
- )
- def lt(val):
- """
- A validator that raises `ValueError` if the initializer is called
- with a number larger or equal to *val*.
- :param 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*.
- :param 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*.
- :param 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*.
- :param val: Exclusive lower bound for values
- .. versionadded:: 21.3.0
- """
- return _NumberValidator(val, ">", operator.gt)
- @attrs(repr=False, frozen=True, slots=True)
- class _MaxLengthValidator(object):
- 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:
- raise ValueError(
- "Length of '{name}' must be <= {max}: {len}".format(
- name=attr.name, max=self.max_length, len=len(value)
- )
- )
- def __repr__(self):
- return "<max_len validator for {max}>".format(max=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*.
- :param int length: Maximum length of the string or iterable
- .. versionadded:: 21.3.0
- """
- return _MaxLengthValidator(length)
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