Source code for magni.utils.validation._generic

"""
..
    Copyright (c) 2014-2017, Magni developers.
    All rights reserved.
    See LICENSE.rst for further information.

Module providing the `validate_generic` function.

Routine listings
----------------
validate_generic(name, type, value_in=None, len_=None, keys_in=None,
    has_keys=None, superclass=None, ignore_none=False, var=None)
    Validate non-numeric objects.

"""

from __future__ import absolute_import
from __future__ import division

import types

from magni.utils.validation._util import get_var as _get_var
from magni.utils.validation._util import report as _report


try:
    unicode = unicode
except NameError:
    _string = (str, bytes)
else:
    _string = (str, unicode)

_types = {'string': _string,
          'explicit collection': (list, tuple),
          # 'implicit collection': ...,
          # 'collection': ...,
          'mapping': dict,
          'function': types.FunctionType,
          'class': type}


[docs]def validate_generic(name, type_, value_in=None, len_=None, keys_in=None, has_keys=None, superclass=None, ignore_none=False, var=None): """ Validate non-numeric objects. The present function is meant to validate the type or class of an object. Furthermore, if the object may only take on a limited number of values, the object can be validated against this list. In the case of collections (for example lists and tuples) and mappings (for example dictionaries), a specific length can be required. Furthermore, in the case of mappings, the keys can be validated by requiring and/or only allowing certain keys. If the present function is called with `name` set to None, an iterable with the value 'generic' followed by the remaining arguments passed in the call is returned. This is useful in combination with the validation function `magni.utils.validation.validate_levels`. Parameters ---------- name : None The name of the variable to be validated. type_ : None One or more references to groups of types, specific types, and/or specific classes. value_in : set-like The list of values accepted. (the default is None, which implies that all values are accepted) len_ : int The length required. (the default is None, which implies that all lengths are accepted) keys_in : set-like The list of accepted keys. (the default is None, which implies that all keys are accepted) has_keys : set-like The list of required keys. (the default is None, which implies that no keys are required) superclass : class The required superclass. (the default is None, which implies that no superclass is required) ignore_none : bool A flag indicating if the variable is allowed to be none. (the default is False) var : None The value of the variable to be validated. See Also -------- magni.utils.validation.validate_levels : Validate contained objects. magni.utils.validation.validate_numeric : Validate numeric objects. Notes ----- `name` must refer to a variable in the parent scope of the function or method decorated by `magni.utils.validation.decorate_validation` which is closest to the top of the call stack. If `name` is a string then there must be a variable of that name in that scope. If `name` is a set-like object then there must be a variable having the first value in that set-like object as name. The remaining values are used as keys/indices on the variable to obtain the variable to be validated. For example, the `name` ('name', 0, 'key') refers to the variable "name[0]['key']". `type_` is either a single value treated as a list with one value or a set-like object containing at least one value. Each value is either a specific type or class, or it refers to one or more types by having one of the string values 'string', 'explicit collection', 'implicict collection', 'collection', 'mapping', 'function', 'class'. - 'string' tests if the variable is a str. - 'explicit collection' tests if the variable is a list or tuple. - 'implicit collection' tests if the variable is iterable. - 'collection' is a combination of the two above. - 'mapping' tests if the variable is a dict. - 'function' tests if the variable is a function. - 'class' tests if the variable is a type. `var` can be used to pass the value of the variable to be validated. This is useful either when the variable cannot be looked up by `name` (for example, if the variable is a property of the argument of a function) or to remove the overhead of looking up the value. Examples -------- Every public function and method of the present package (with the exception of the functions of this subpackage itself) validates every argument and keyword argument using the functionality of this subpackage. Thus, for examples of how to use the present function, browse through the code. """ if name is None: return ('generic', type_, value_in, len_, keys_in, has_keys, superclass, ignore_none) if var is None: var = _get_var(name) if var is None: if not isinstance(ignore_none, bool): _report(TypeError, 'must be {!r}.', bool, var_name='ignore_none', var_value=ignore_none, expr='type({})', prepend='Invalid validation call: ') if ignore_none: return else: _report(ValueError, 'must not be {!r}.', None, var_name=name) if isinstance(type_, (str, type)) or not hasattr(type_, '__iter__'): type_ = (type_,) _check_type(name, var, type_) _check_value(name, var, value_in) _check_len(name, var, len_) _check_keys(name, var, keys_in, has_keys) _check_inheritance(name, var, superclass)
[docs]def _check_inheritance(name, var, superclass): """ Check the superclasses of a variable. Parameters ---------- name : None The name of the variable to be validated. var : None The value of the variable to be validated. superclass : class The required superclass. """ if superclass is not None: if not isinstance(superclass, type): _report(TypeError, 'must be a type.', var_name='superclass', var_value=superclass, prepend='Invalid validation call: ') if not issubclass(var, superclass): _report(TypeError, 'must be a subclass of {!r}.', superclass, var_name=name)
[docs]def _check_keys(name, var, keys_in, has_keys): """ Check the keys of a variable. Parameters ---------- name : None The name of the variable to be validated. var : None The value of the variable to be validated. keys_in : set-like The allowed keys. has_keys : set-like The required keys. """ if keys_in is not None: if not isinstance(keys_in, (list, tuple)): _report(TypeError, 'must be in {!r}.', (list, tuple), var_name='keys_in', var_value=keys_in, prepend='Invalid validation call: ') for key in var.keys(): if key not in keys_in: _report(KeyError, 'must be in {!r}.', keys_in, var_name=name, expr='{}.keys()') if has_keys is not None: if not isinstance(has_keys, (list, tuple)): _report(TypeError, 'must be in {!r}.', (list, tuple), var_name='has_keys', var_value=has_keys, prepend='Invalid validation call: ') for key in has_keys: if key not in var.keys(): _report(KeyError, 'must have the key {!r}.', key, var_name=name)
[docs]def _check_len(name, var, len_): """ Check the length of a variable. Parameters ---------- name : None The name of the variable to be validated. var : None The value of the variable to be validated. len_ : int The required length. """ if len_ is not None: if not isinstance(len_, int): _report(TypeError, 'must be {!r}.', int, var_name='len_', var_value=len_, expr='type({})', prepend='Invalid validation call: ') if not hasattr(var, '__len__') or len(var) != len_: _report(ValueError, 'must be {!r}.', len_, var_name=name, expr='len({})')
[docs]def _check_type(name, var, types_): """ Check the type of a variable. Parameters ---------- name : None The name of the variable to be validated. var : None The value of the variable to be validated. types_ : set-like The allowed types. """ valid = False for type_ in types_: if isinstance(type_, type): if isinstance(var, type_): valid = True break elif type_ in _types.keys(): if isinstance(var, _types[type_]): valid = True break elif type_ in ('implicit collection', 'collection'): if hasattr(var, '__iter__'): valid = True break else: _report(ValueError, 'must be a valid type.', var_name='type_', var_value=type_, prepend='Invalid validation call: ') if not valid: _report(TypeError, 'must be in {!r}.', types_, var_name=name, expr='type({})')
[docs]def _check_value(name, var, value_in): """ Check the value of a variable. Parameters ---------- name : None The name of the variable to be validated. var : None The value of the variable to be validated. value_in : set-like The allowed values. """ if value_in is not None: if not isinstance(value_in, (list, tuple)): _report(TypeError, 'must be in {!r}.', (list, tuple), var_name='value_in', var_value=value_in, prepend='Invalid validation call: ') if var not in value_in: _report(ValueError, 'must be in {!r}.', value_in, var_name=name)