This decorator caches returning value from a function/method

utils.py

# I suggest you use memcached or redis as backend

import time
import json
from functools import wraps


def cached(timeout=1800):
    def wrapper(f):
        @wraps(f)
        def inner_wrapper(*args, **kwargs):
            func_name = '{0}.{1}'.format(f.__module__, f.__name__)
            cached_data = CACHE_BACKEND.get(func_name)
            if cached_data:
                data = json.loads(cached_data)
                if data.get('created_at', 0) >= time.time() - timeout and data.get('params') == [list(args), kwargs]:
                    return data.get('value')

            value = f(*args, **kwargs)
            cache_data = json.dumps({'created_at': time.time(), 'value': value, 'params': [args, kwargs]})
            if len(cache_data) <= SERVER_MAX_VALUE_LENGTH:
                CACHE_BACKEND.set(func_name, cache_data)

            return value

        return inner_wrapper
    return wrapper