from __future__ import absolute_import, print_function, unicode_literals import functools import collections def save_method_args(method): """ Wrap a method such that when it is called, the args and kwargs are saved on the method. >>> class MyClass(object): ... @save_method_args ... def method(self, a, b): ... print(a, b) >>> my_ob = MyClass() >>> my_ob.method(1, 2) 1 2 >>> my_ob._saved_method.args (1, 2) >>> my_ob._saved_method.kwargs {} >>> my_ob.method(a=3, b='foo') 3 foo >>> my_ob._saved_method.args () >>> my_ob._saved_method.kwargs == dict(a=3, b='foo') True The arguments are stored on the instance, allowing for different instance to save different args. >>> your_ob = MyClass() >>> your_ob.method({str('x'): 3}, b=[4]) {'x': 3} [4] >>> your_ob._saved_method.args ({'x': 3},) >>> my_ob._saved_method.args () """ args_and_kwargs = collections.namedtuple('args_and_kwargs', 'args kwargs') @functools.wraps(method) def wrapper(self, *args, **kwargs): attr_name = '_saved_' + method.__name__ attr = args_and_kwargs(args, kwargs) setattr(self, attr_name, attr) return method(self, *args, **kwargs) return wrapper