TangoMan PyValidator

A dynamic runtime typing validation for members annotated with PEP 484 type hints.

TangoMan PyValidator idea was inspired by agronholm / typeguard but enforces SOLID principles, and is based on the chain-of-responsibility design pattern which makes it more readable, extensible and maintenable.

TangoMan PyValidator provides @Validator.type_check decorator as a mean to dynamically check for type violations at runtime.

Install

Enter following command to install locally

$ sudo python3 setup.py install
# or
$ pip3 install git+https://github.com/TangoMan75/pyvalidator

Features

Validator

• Validate typing aliases recursively.
• Validate standard python types.
• Validate classes.
• Validate nullable properties.
• Validate not blank properties.

pyfunctools

Python utilities to handle reflexion methods on functions.

Usage

Import typing module and extend your class with Validator

import typing

from pyvalidator.validator import Validator

class Foobar(Validator):
	# ...

type_check

Document your class with appropriate annotations and use @Validator.type_check decorator on your method and properties.

    @property
    def nullable_str(self) -> typing.Optional[str]:
        return self._nullable_str

    @nullable_str.setter
    @Validator.type_check
    def nullable_str(self, nullable_str_: typing.Optional[str]) -> None:
        self._nullable_str = nullable_str_

At runtime if any given argument does not match expected type, Validator will raise a TypeError.

not_blank

Use @Validator.not_blank decorator on your method and properties.

    @Validator.not_blank
    def divide(self, a: int, b: int) -> None:
    	return a / b

At runtime Validator will raise a ValueError if any given argument is empty i.e:

• bytes equals b''
• bytearray equals bytearray()
• complex equals 0j
• dict equals {}
• float equals 0.0
• frozenset equals frozenset()
• int equals 0
• list equals []
• memoryview equals memoryview(b'')
• range equals range(0)
• set equals set()
• str equals ''
• tuple equals ()

NOTE: "bool" and "type" values excluded, since "not blank" does not make sense with them.

Decorator

Decorators are chainable, you can use @Validator.type_check and @Validator.not_blank on the same attribute.

    @property
    def email(self) -> typing.Optional[str]:
        return self._email

    @email.setter
    @Validator.type_check
    @Validator.not_blank
    def email(self, email_: typing.Optional[str]) -> None:
        self._email = email_

Known bug

typing.OrderedDict causes AttributeError at runtime (which causes travis ci to fail):

AttributeError: module 'typing' has no attribute 'OrderedDict'

Seems like mypy maintainers don't want to fix the issue python/mypy#6904

Continuous Integration

If you find any bug please report here : Issues

License

Copyrights (c) 2020 "Matthias Morin" <mat@tangoman.io>

Distributed under the MIT license.

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