At the command line:
$ pip install fqn-decorators
.. py:currentmodule:: fqn_decorators.decorators
By extending the :class:`~Decorator` class you can create simple decorators. Implement the :meth:`~Decorator.before` and/or :meth:`~Decorator.after` methods to perform actions before or after execution of the decorated item. The :meth:`~Decorator.before` method can access the arguments of the decorated item by changing the :attr:`~Decorator.args` and :attr:`~Decorator.kwargs` attributes. The :meth:`~Decorator.after` method can access or change the result using the :attr:`~Decorator.result` attribute. The :meth:`~Decorator.exception` method can be used for do something with an Exception that has been raised. In all three methods the :attr:`~Decorator.fqn` and :attr:`~Decorator.func` attributes are available.
Create a simple decorator:
import fqn_decorators import time class time_it(fqn_decorators.Decorator): def before(self): self.start = time.time() def after(self): duration = time.time() - self.start print("{0} took {1} seconds".format(self.fqn, duration)) @time_it def my_function(): time.sleep(1) >>>my_function() __main__.my_function took 1.00293397903 seconds
It is also very easy to create a decorator with arguments.
Note
It is not possible to create decorators with non-keyworded arguments. To create a decorator that supports non-keyworded arguments see the :ref:`Advanced Usage <usage_advanced_non_keyword_decorators>` section.
Example:
import fqn_decorators import time class threshold(fqn_decorators.Decorator): def before(self): self.start = time.time() def after(self): duration = time.time() - self.start treshold = self.params.get('threshold') if threshold and duration > threshold: raise Exception('Execution took longer than the threshold') @threshold(threshold=2) def my_function(): time.sleep(3) >>> my_function() Exception: Execution took longer than the threshold