Advanced decorator builder / customization

advanced_decorators.py

"""
Exploring some ideas around customizable decorators that derive default
values from a config or instance.
"""

from functools import wraps

# Simple customizable decorator.


def deco_factory(prefix=''):
    """Decorator factory that saves some config options.

    This is for all decorator calls.
    """
    def outer(func):
        @wraps(func)
        def inner(*args, **kwargs):
            print('{0} Woot!'.format(prefix))
            return func(*args, **kwargs)
        return inner
    return outer


adeco = deco_factory(prefix='<>')


@adeco
def myfunc():
    print('hello this is my func.')
    print('\n')


myfunc()


# More involved class based config.
# The important distinction being it is a class instance that can
# have more configuration, and properties.


class Wrapper(object):

    def __init__(self, prefix='', default_msg='Hello!'):
        self._prefix = prefix
        self._msg = default_msg

    @property
    def prefix(self):
        return self._prefix

    def get_helper(self):
        def outer(func):
            @wraps(func)
            def inner(*args, **kwargs):
                print('{0} {1}'.format(self._prefix, self._msg))
                return func(*args, **kwargs)
            return inner
        return outer

    def get_helper2(self):
        """A more involved, customizeable decorator.

        Customized at the class level, and also per-call.
        """
        def _f(extra=None):
            def outer(func):
                @wraps(func)
                def inner(*args, **kwargs):
                    if extra is not None:
                        print('This is the extra stuff! ')
                        print(extra)
                        print('End extra stuff!')
                    print('{0} {1}'.format(self._prefix, self._msg))
                    return func(*args, **kwargs)
                return inner
            return outer
        return _f


mywrapper = Wrapper(prefix='><', default_msg='Good day!')

@mywrapper.get_helper()
def myfunc2():
    print('hello this is my func.')
    print('\n')

wrapper2 = mywrapper.get_helper2()

@wrapper2(extra='Weeee')
def myfunc3():
    print('hello this is my func2.')
    print('\n')


myfunc2()
myfunc3()