'''
:Author: Juti Noppornpitak
:Availability: 1.5
The module contains reusable input validators.
.. note::
Copyright (c) 2012 Juti Noppornpitak
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''
try:
from inspect import getfullargspec
except ImportError as e:
# Fall back to Python 2.7 mode
from inspect import getargspec as getfullargspec
import sys
from imagination.exception import MisplacedValidatorError
_disable_decorator = 'sphinx' in sys.modules
class SpecialType(object):
function = 'type:function'
[docs]def restrict_type(*restricted_list, **restricted_map):
'''
The method decorator to validate the type of inputs given to the method.
:param `restricted_list`: the list of types to restrict the type of each
parameter in the same order as the parameter given
to the method.
:param `restricted_map`: the map of types to restrict the type of each
parameter by name.
When the input fails the validation, an exception of type :class:`TypeError`
is throw.
There are a few exceptions:
* If the given type is ``None``, there will be no restriction.
* If the given type is ``long``, the value of ``int`` and ``float`` are also valid.
* If the given type is ``unicode``, the valud of ``str`` is also valid.
.. warning:: In Imagination 1.6, types ``unicode`` and ``long`` are no longer have fallback check in order to support Python 3.3.
.. code-block:: python
from imagination.decorator.validator import restrict_type
# Example on a function
@restrict_type(unicode)
def say(context):
print context
class Person(object):
# Example on a constructor
@restrict_type(unicode, int)
def __init__(self, name, age):
self.name = name
self.age = age
self.__friends = []
# Example on an instance method
@restrict_type(Person)
def add_friend(self, person):
self.__friends.append(person)
'''
def inner_decorator(reference):
if _disable_decorator:
return reference
if isinstance(reference, type) or not callable(reference):
raise MisplacedValidatorError(
'Can only be used with callable objects, e.g., functions, class methods, instance methods and static methods.'
)
params = getfullargspec(reference).args
is_class = params and params[0] == 'self'
if is_class:
def new_reference(self, *args, **kwargs):
__validate_type(restricted_list, restricted_map, args, kwargs)
return reference(self, *args, **kwargs)
else:
def new_reference(*args, **kwargs):
__validate_type(restricted_list, restricted_map, args, kwargs)
return reference(*args, **kwargs)
new_reference.__doc__ == reference.__doc__
return new_reference
return inner_decorator
def __validate_type(allowed_list, allowed_dictionary, argument_list, argument_dictionary):
allowed_list = allowed_list[:len(argument_list)]
reference = None
try:
for index in range(len(allowed_list)):
expected_type = allowed_list[index]
reference = argument_list[index]
if not expected_type:
continue
assert __assert_type(reference, expected_type),\
expected_type == SpecialType.function\
and 'function'\
or expected_type.__name__
for key in allowed_dictionary:
expected_type = allowed_dictionary[key]
if key not in argument_dictionary:
continue
reference = argument_dictionary[key]
if not expected_type:
continue
assert __assert_type(reference, expected_type),\
expected_type.__name__
except AssertionError as e:
actual_type = e.message if 'message' in dir(e) else e
raise TypeError('Argument #%s was excepting %s but %s has been given.' % (index, actual_type, type(reference).__name__))
def __assert_type(instance, expected_type):
list_types = [list, tuple, set]
callable_expected = expected_type == SpecialType.function
instance_expected = isinstance(expected_type, type)
if not callable_expected and not instance_expected:
raise TypeError('The expected type must be a type.')
fallback_types = []
# If the callable is expected, validate if it is callable.
if callable_expected:
return callable(instance)
# Now, validate the type of INSTANCE.
if expected_type in list_types:
fallback_types.extend(list_types)
if type(instance) == expected_type or isinstance(instance, expected_type):
return True
for fallback_type in fallback_types:
if type(instance) == fallback_type:
return True
return False