Python: caching the values of functions at certain times

function_cache.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from datetime import timedelta, datetime
from time import sleep
from functools import partial


class Cache(object):
    """Class caching function's results for some time.

    Using:

    cache = Cache(max_time_default)

    @cache
    def some_function(*args, **kwargs)
        return someone

    Also, every function can save any max time. Call this function with argument "max_age":

    some_function(args, kwargs, max_age=4)
    """

    def __init__(self, max_time_default, *args, **kwargs):
        self.cached_responses = {}
        self.max_time_default = max_time_default if max_time_default else 0

    def __call__(self, function):
        def wrapped(*args, **kwargs):
            max_time = kwargs.get('max_age', None)

            if max_time:
                del kwargs['max_age']

            if not max_time:
                max_time = self.max_time_default

            if self.cached_responses.get(function, None):
                last_added_time = self.cached_responses[function].get('datetime')
            else:
                last_added_time = None

            if last_added_time and (datetime.now() - last_added_time).seconds > max_time or not last_added_time:
                response = function(*args, **kwargs)

                self.cached_responses[function] = {
                    'datetime': datetime.now(),
                    'response': response
                }
                return response
            else:
                return self.cached_responses[function]['response']

        wrapped.__name__ = function.__name__
        return wrapped

if __name__ == '__main__':
    cache = Cache(max_time_default=2)
    
    @cache  # < --- Add decorator of cache for function
    def func(a):
      return a
    
    print func(1) # Return 1: function not called earlier, will call
    print func(2) # Return 1: cached value of function
    sleep(5)
    print func(3) # Return 3: cached value is old, will call again
    sleep(5)
    print func(4, max_age=10) # Return 3: max age was changed