leex4418/python-aop

Python AOP Framework

Python AOP Framework

Python AOP Framework is a minimal Framework to use Aspect-Oriented Programming on your Python applications

Examples

Definition of Aspects

>>> import logging
>>> from aop import Aspect
>>> 
>>> class InvocationLoggerAspect(Aspect):
...     def __init__(self, *args, **kwargs):
...         super().__init__(*args, **kwargs)
...         self.logger = logging.getLogger('python-aop')
...         self.logger.setLevel(logging.DEBUG)
...     
...         fh = logging.FileHandler('auth.log')
...         fh.setLevel(logging.DEBUG)
...     
...         self.logger.addHandler(fh)
...     
...     def before(self, *args, **kwargs):
...         self.logger.info(
...             'Invocation: name=%s, args=%s, kwargs=%s' % (
...                 self.function,
...                 args,
...                 kwargs
...             )
...         )
... 
>>> 

Use of Aspect over functions

If we want to log each invocation attempt we can apply the aspect directly to a function

>>> def auth(user, password):
...     if user == 'aop' and password == '#$%3&23%#$(%':
...         return True
...     return False
... 
>>> 
>>> auth = InvocationLoggerAspect(auth)
>>> 
>>> auth('aop', '#$%3&23%#$(%')
True
>>> auth('aop', '')
False
>>>

The content of auth.log:

Invocation: name=<function auth at 0x7f1e30282290>, args=('aop', '#$%3&23%#$(%'), kwargs={}
Invocation: name=<function auth at 0x7f1e30282290>, args=('aop', ''), kwargs={}

Use of AspectType

>>> import logging
>>> from aop import Aspect, AspectType
>>> 
>>> class InvocationLoggerAspect(Aspect):
...     def __init__(self, *args, **kwargs):
...         super().__init__(*args, **kwargs)
...         self.logger = logging.getLogger('python-aop')
...         self.logger.setLevel(logging.DEBUG)
...         
...         fh = logging.FileHandler('auth.log')
...         fh.setLevel(logging.DEBUG)
...         
...         self.logger.addHandler(fh)
...     
...     def before(self, *args, **kwargs):
...         self.logger.info(
...             'Invocation: name=%s, args=%s, kwargs=%s' % (
...                 self.function,
...                 args,
...                 kwargs
...             )
...         )
... 
>>> 
>>> class AuthenticationBackend(metaclass=AspectType):
...     def auth(self, user, password):
...         if user == 'aop' and password == '#$%3&23%#$(%':
...             return True
...         return False
... 
>>> AuthenticationBackend.pointcut('auth', InvocationLoggerAspect)
>>> 
>>> backend = AuthenticationBackend()
>>> backend.auth('aop', '#$%3&23%#$(%')
True
>>> backend.auth('aop', '')
False
>>>