lru_cache的增强实现

from functools import wraps
import time,inspect,datetime

def m_cache(duration):
    def _cache(fn):
        local_cache={}
        @wraps(fn)
        def wrapper(*args,**kwargs):
            def clear_expire_keys(cache):
                expire_keys=[] # 记录过期key
                for k,(_,timestamp) in cache.items(): # 寻找过期key
                    if datetime.datetime.now().timestamp()-timestamp > duration:
                        expire_keys.append(k)
                for k in expire_keys: # 清除过期key
                    local_cache.pop(k)
            
            clear_expire_keys(local_cache)
            
            def make_key():
                key_dict={}
                sig=inspect.signature(fn)
                od=sig.parameters
                # param_list=[key for key in od.keys()]
                param_list=list(od.keys()) # inspect获取的参数列表
    
                # positional arguments
                for index,v in enumerate(args):
                    # print(index,v)
                    k=param_list[index]
                    key_dict[k]=v
    
                # keywords arguments
                for k,v in kwargs.items():
                    key_dict[k]=v
                # key_dict.update(kwargs)
                for k in od.keys(): # 对缺省参数的处理,置于key生成前
                    if k not in key_dict.keys():
                        key_dict[k]=od[k].default
    
                return tuple(sorted(key_dict.items()))
            key=make_key()
            
            print(key)
            
            if key not in local_cache.keys():
                ret=fn(*args,**kwargs)
                local_cache[key]=ret,datetime.datetime.now().timestamp()
            return local_cache[key][0]
        return wrapper
    return _cache

def logger(fn):
    @wraps(fn)
    def wrapper(*args,**kwargs):
        start=datetime.datetime.now()
        ret=fn(*args,**kwargs)
        delta=(datetime.datetime.now()-start).total_seconds()
        print(delta)
        return ret
    return wrapper

@logger
@m_cache(3)
def dix(x,y=6,z=3):
    time.sleep(z)
    print(‘x: {}\ty: {}‘.format(x,y))
    print(‘\n‘*3)
    return x+y
print(dix(7))
print(dix(7,y=6))
print(dix(x=7,y=6))
print(dix(y=6,x=7))
print(dix(4,8,y=6,x=7)) # 不符合原函数的定义,但是形成key一样,直接从local_cache取结果,避免了函数的的真正执行,故未报错

time.sleep(4)

print(dix(7))
print(dix(7,y=6))
print(dix(x=7,y=6))
print(dix(y=6,x=7))
print(dix(4,8,y=6,x=7))