The Redis cache example is implemented in Python using AOP

Caching is increasingly considered to be the most NB invention in computer science. This article presents an example of Redis caching using AOP in Python

import redis 
enable=True 
#enable=False 
def readRedis(key): 
  if enable: 
    r = redis.Redis(host='10.224.38.31', port=8690,db=0, password='xxxx')   
    val = r.get(key) 
    if val is None: 
      print "can not find data for KEY:%s \n" % (key) 
      return None 
    else: 
      print "====Get VALUE from Redis by KEY:%s \n" % ( key) 
      return pickle.loads(val) 
  else: 
    print "disable cache" 
   
def writeRedis(key, val): 
  r = redis.Redis(host='10.224.38.31', port=8690,db=0, password='xxxx') 
  if val is None: 
    print "Val is None, don't save it to redis \n" 
  else: 
    r.set(key, pickle.dumps(val) ) 
    r.expire(key, 60*60*24*7) #1week 
    print "====Write value of KEY:%s to redis \n" % (key) 
   
import pickle, functools 
def cache(f): 
 def wrapper(*args, **kwargs): 
  key = pickle.dumps((f.__name__, args, kwargs)).replace("\n","") 
  val = readRedis(key) 
  if val is None: 
   val = f(*args, **kwargs) # call the wrapped function, save in cache 
   writeRedis(key, val) 
  return val # read value from cache 
 functools.update_wrapper(wrapper, f) # update wrapper's metadata 
 return wrapper  
 
@cache 
def foo(n): 
 return n*2 
 
foo(10) # first call with parameter 10, sleeps 
foo(10) # returns immediately 
foo(15) # returns immediately 
foo(19) # returns immediately