from datetime import datetime, timedelta
from copy import deepcopy
from threading import RLock

def timed_cache(seconds=0, minutes=0, hours=0, days=0):

    time_delta = timedelta( seconds=seconds,
                            minutes=minutes,
                            hours=hours,
                            days=days )

    def decorate(f):

        f._lock = RLock()
        f._updates = {}
        f._results = {}

        def do_cache(*args, **kwargs):

            lock = f._lock
            lock.acquire()

            try:
                key = (args, tuple(sorted(kwargs.items(), key=lambda i:i[0])))

                updates = f._updates
                results = f._results

                t = datetime.now()
                updated = updates.get(key, t)

                if key not in results or t-updated > time_delta:
                    # Calculate
                    updates[key] = t
                    result = f(*args, **kwargs)
                    results[key] = deepcopy(result)
                    return result

                else:
                    # Cache
                    return deepcopy(results[key])

            finally:
                lock.release()

        return do_cache

    return decorate

http://www.willmcgugan.com/blog/tech/2007/10/14/timed-caching-decorator/

Caching decorator

Python