380 lines
11 KiB
Python
380 lines
11 KiB
Python
"""
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Commonly useful validators.
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"""
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from __future__ import absolute_import, division, print_function
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import re
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from ._make import _AndValidator, and_, attrib, attrs
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from .exceptions import NotCallableError
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__all__ = [
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"and_",
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"deep_iterable",
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"deep_mapping",
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"in_",
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"instance_of",
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"is_callable",
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"matches_re",
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"optional",
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"provides",
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]
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@attrs(repr=False, slots=True, hash=True)
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class _InstanceOfValidator(object):
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type = attrib()
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if not isinstance(value, self.type):
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raise TypeError(
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"'{name}' must be {type!r} (got {value!r} that is a "
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"{actual!r}).".format(
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name=attr.name,
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type=self.type,
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actual=value.__class__,
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value=value,
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),
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attr,
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self.type,
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value,
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)
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def __repr__(self):
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return "<instance_of validator for type {type!r}>".format(
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type=self.type
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)
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def instance_of(type):
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"""
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A validator that raises a `TypeError` if the initializer is called
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with a wrong type for this particular attribute (checks are performed using
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`isinstance` therefore it's also valid to pass a tuple of types).
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:param type: The type to check for.
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:type type: type or tuple of types
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:raises TypeError: With a human readable error message, the attribute
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(of type `attr.Attribute`), the expected type, and the value it
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got.
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"""
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return _InstanceOfValidator(type)
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@attrs(repr=False, frozen=True, slots=True)
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class _MatchesReValidator(object):
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regex = attrib()
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flags = attrib()
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match_func = attrib()
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if not self.match_func(value):
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raise ValueError(
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"'{name}' must match regex {regex!r}"
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" ({value!r} doesn't)".format(
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name=attr.name, regex=self.regex.pattern, value=value
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),
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attr,
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self.regex,
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value,
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)
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def __repr__(self):
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return "<matches_re validator for pattern {regex!r}>".format(
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regex=self.regex
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)
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def matches_re(regex, flags=0, func=None):
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r"""
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A validator that raises `ValueError` if the initializer is called
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with a string that doesn't match *regex*.
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:param str regex: a regex string to match against
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:param int flags: flags that will be passed to the underlying re function
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(default 0)
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:param callable func: which underlying `re` function to call (options
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are `re.fullmatch`, `re.search`, `re.match`, default
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is ``None`` which means either `re.fullmatch` or an emulation of
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it on Python 2). For performance reasons, they won't be used directly
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but on a pre-`re.compile`\ ed pattern.
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.. versionadded:: 19.2.0
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"""
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fullmatch = getattr(re, "fullmatch", None)
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valid_funcs = (fullmatch, None, re.search, re.match)
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if func not in valid_funcs:
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raise ValueError(
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"'func' must be one of %s."
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% (
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", ".join(
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sorted(
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e and e.__name__ or "None" for e in set(valid_funcs)
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)
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),
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)
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)
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pattern = re.compile(regex, flags)
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if func is re.match:
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match_func = pattern.match
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elif func is re.search:
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match_func = pattern.search
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else:
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if fullmatch:
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match_func = pattern.fullmatch
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else:
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pattern = re.compile(r"(?:{})\Z".format(regex), flags)
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match_func = pattern.match
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return _MatchesReValidator(pattern, flags, match_func)
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@attrs(repr=False, slots=True, hash=True)
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class _ProvidesValidator(object):
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interface = attrib()
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if not self.interface.providedBy(value):
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raise TypeError(
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"'{name}' must provide {interface!r} which {value!r} "
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"doesn't.".format(
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name=attr.name, interface=self.interface, value=value
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),
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attr,
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self.interface,
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value,
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)
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def __repr__(self):
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return "<provides validator for interface {interface!r}>".format(
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interface=self.interface
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)
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def provides(interface):
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"""
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A validator that raises a `TypeError` if the initializer is called
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with an object that does not provide the requested *interface* (checks are
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performed using ``interface.providedBy(value)`` (see `zope.interface
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<https://zopeinterface.readthedocs.io/en/latest/>`_).
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:param interface: The interface to check for.
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:type interface: ``zope.interface.Interface``
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:raises TypeError: With a human readable error message, the attribute
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(of type `attr.Attribute`), the expected interface, and the
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value it got.
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"""
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return _ProvidesValidator(interface)
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@attrs(repr=False, slots=True, hash=True)
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class _OptionalValidator(object):
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validator = attrib()
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def __call__(self, inst, attr, value):
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if value is None:
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return
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self.validator(inst, attr, value)
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def __repr__(self):
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return "<optional validator for {what} or None>".format(
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what=repr(self.validator)
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)
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def optional(validator):
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"""
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A validator that makes an attribute optional. An optional attribute is one
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which can be set to ``None`` in addition to satisfying the requirements of
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the sub-validator.
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:param validator: A validator (or a list of validators) that is used for
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non-``None`` values.
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:type validator: callable or `list` of callables.
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.. versionadded:: 15.1.0
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.. versionchanged:: 17.1.0 *validator* can be a list of validators.
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"""
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if isinstance(validator, list):
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return _OptionalValidator(_AndValidator(validator))
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return _OptionalValidator(validator)
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@attrs(repr=False, slots=True, hash=True)
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class _InValidator(object):
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options = attrib()
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def __call__(self, inst, attr, value):
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try:
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in_options = value in self.options
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except TypeError: # e.g. `1 in "abc"`
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in_options = False
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if not in_options:
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raise ValueError(
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"'{name}' must be in {options!r} (got {value!r})".format(
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name=attr.name, options=self.options, value=value
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)
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)
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def __repr__(self):
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return "<in_ validator with options {options!r}>".format(
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options=self.options
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)
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def in_(options):
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"""
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A validator that raises a `ValueError` if the initializer is called
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with a value that does not belong in the options provided. The check is
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performed using ``value in options``.
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:param options: Allowed options.
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:type options: list, tuple, `enum.Enum`, ...
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:raises ValueError: With a human readable error message, the attribute (of
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type `attr.Attribute`), the expected options, and the value it
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got.
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.. versionadded:: 17.1.0
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"""
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return _InValidator(options)
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@attrs(repr=False, slots=False, hash=True)
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class _IsCallableValidator(object):
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if not callable(value):
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message = (
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"'{name}' must be callable "
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"(got {value!r} that is a {actual!r})."
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)
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raise NotCallableError(
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msg=message.format(
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name=attr.name, value=value, actual=value.__class__
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),
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value=value,
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)
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def __repr__(self):
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return "<is_callable validator>"
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def is_callable():
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"""
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A validator that raises a `attr.exceptions.NotCallableError` if the
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initializer is called with a value for this particular attribute
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that is not callable.
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.. versionadded:: 19.1.0
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:raises `attr.exceptions.NotCallableError`: With a human readable error
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message containing the attribute (`attr.Attribute`) name,
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and the value it got.
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"""
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return _IsCallableValidator()
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@attrs(repr=False, slots=True, hash=True)
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class _DeepIterable(object):
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member_validator = attrib(validator=is_callable())
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iterable_validator = attrib(
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default=None, validator=optional(is_callable())
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)
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if self.iterable_validator is not None:
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self.iterable_validator(inst, attr, value)
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for member in value:
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self.member_validator(inst, attr, member)
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def __repr__(self):
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iterable_identifier = (
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""
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if self.iterable_validator is None
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else " {iterable!r}".format(iterable=self.iterable_validator)
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)
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return (
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"<deep_iterable validator for{iterable_identifier}"
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" iterables of {member!r}>"
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).format(
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iterable_identifier=iterable_identifier,
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member=self.member_validator,
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)
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def deep_iterable(member_validator, iterable_validator=None):
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"""
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A validator that performs deep validation of an iterable.
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:param member_validator: Validator to apply to iterable members
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:param iterable_validator: Validator to apply to iterable itself
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(optional)
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.. versionadded:: 19.1.0
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:raises TypeError: if any sub-validators fail
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"""
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return _DeepIterable(member_validator, iterable_validator)
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@attrs(repr=False, slots=True, hash=True)
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class _DeepMapping(object):
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key_validator = attrib(validator=is_callable())
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value_validator = attrib(validator=is_callable())
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mapping_validator = attrib(default=None, validator=optional(is_callable()))
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def __call__(self, inst, attr, value):
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"""
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We use a callable class to be able to change the ``__repr__``.
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"""
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if self.mapping_validator is not None:
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self.mapping_validator(inst, attr, value)
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for key in value:
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self.key_validator(inst, attr, key)
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self.value_validator(inst, attr, value[key])
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def __repr__(self):
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return (
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"<deep_mapping validator for objects mapping {key!r} to {value!r}>"
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).format(key=self.key_validator, value=self.value_validator)
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def deep_mapping(key_validator, value_validator, mapping_validator=None):
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"""
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A validator that performs deep validation of a dictionary.
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:param key_validator: Validator to apply to dictionary keys
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:param value_validator: Validator to apply to dictionary values
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:param mapping_validator: Validator to apply to top-level mapping
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attribute (optional)
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.. versionadded:: 19.1.0
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:raises TypeError: if any sub-validators fail
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"""
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return _DeepMapping(key_validator, value_validator, mapping_validator)
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