从类到装饰器的python3自变量
我正在尝试构建我的第一个装饰器并在类中实现它从类到装饰器的python3自变量,python,python-3.x,python-3.5,Python,Python 3.x,Python 3.5,我正在尝试构建我的第一个装饰器并在类中实现它 # decorator class class Cache(object): def __init__(self,filename,**kwargs): self.time_ago = datetime.now() - timedelta(**kwargs) self.filename = filename def __call__(self,fn): if not os.path.isfile(self.filen
# decorator class
class Cache(object):
def __init__(self,filename,**kwargs):
self.time_ago = datetime.now() - timedelta(**kwargs)
self.filename = filename
def __call__(self,fn):
if not os.path.isfile(self.filename):
return self.cache(fn(self))
time_ago = self.time_ago
filename = self.filename
c_age = datetime.fromtimestamp(os.path.getctime(filename))
m_age = datetime.fromtimestamp(os.path.getmtime(filename))
print (c_age)
print (m_age)
print (time_ago)
if c_age < time_ago or m_age < time_ago:
return self.cache(fn(self))
else:
return self.read()
def cache(self,data):
with open(self.filename,'r+') as ef:
ef.write(data)
return ef.read()
def read(self):
f = open(self.filename,'r')
data = f.read()
f.close()
return data
我这样称呼它:
z = Zabb()
nodes = z.getNodes()
我得到以下错误:
Traceback (most recent call last):
File "./deco.py", line 52, in <module>
nodes = z.getNodes()
TypeError: 'str' object is not callable
回溯(最近一次呼叫最后一次):
文件“/deco.py”,第52行,在
nodes=z.getNodes()
TypeError:“str”对象不可调用
我很快就能做到这一点了。我做错了什么?您需要从
\uuu调用\uu
方法返回一个高阶函数(包装)。添加一个内部方法并返回它
def __call__(self, fn):
def wrapper(*args, **kwargs): # <-- Add this wrapper
if not os.path.isfile(self.filename):
return self.cache(fn(*args, **kwargs))
time_ago = self.time_ago
filename = self.filename
c_age = datetime.fromtimestamp(os.path.getctime(filename))
m_age = datetime.fromtimestamp(os.path.getmtime(filename))
print (c_age)
print (m_age)
print (time_ago)
if c_age < time_ago or m_age < time_ago:
return self.cache(fn(*args, **kwargs))
else:
return self.read()
return wrapper # <-- Return the wrapper
def\uuu调用(self,fn):
def wrapper(*args,**kwargs):#如果您忘记了@deco
语法糖及其真正作用的原因,那么装饰器更容易理解。以你为例,
@Cache('nodes.json',minutes=1)
def getNodes(self):
return "Get Nodes"
真正的意思是:
def getNodes(self):
return "Get Nodes"
getNodes = Cache('nodes.json',minutes=1)(getNodes)
它实际上将Zabb.getNodes
重新绑定到缓存的结果('nodes.json',minutes=1)。\uuuu调用(getNodes)
-这是一个字符串,而不是函数
您要做的是使缓存。\uuuu call\uuuu
返回一个函数,该函数将调用包装为修饰函数,即:
def __call__(self,fn):
def wrapper(*args, **kw):
if not os.path.isfile(self.filename):
return self.cache(fn(self))
time_ago = self.time_ago
filename = self.filename
c_age = datetime.fromtimestamp(os.path.getctime(filename))
m_age = datetime.fromtimestamp(os.path.getmtime(filename))
print (c_age)
print (m_age)
print (time_ago)
if c_age < time_ago or m_age < time_ago:
return self.cache(fn(self))
else:
return self.read()
return wrapper
def\uuu调用(self,fn):
def包装(*参数,**kw):
如果不是os.path.isfile(self.filename):
返回self.cache(fn(self))
time\u ago=self.time\u ago
filename=self.filename
c_age=datetime.fromtimestamp(os.path.getctime(文件名))
m_age=datetime.fromtimestamp(os.path.getmtime(文件名))
打印(c_年龄)
打印(m_年龄)
打印(时间\单位前)
如果c_age
\uuuuuu调用
需要返回高阶函数(已包装)
def __call__(self,fn):
def wrapper(*args, **kw):
if not os.path.isfile(self.filename):
return self.cache(fn(self))
time_ago = self.time_ago
filename = self.filename
c_age = datetime.fromtimestamp(os.path.getctime(filename))
m_age = datetime.fromtimestamp(os.path.getmtime(filename))
print (c_age)
print (m_age)
print (time_ago)
if c_age < time_ago or m_age < time_ago:
return self.cache(fn(self))
else:
return self.read()
return wrapper