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| # encoding: utf-8
"""
--------------------------------------
@describe
@version: 1.0
@project: websockets
@file: test.py
@author: yuanlang
@time: 2019-03-18 14:29
---------------------------------------
"""
# 先看看函数复制
def a():
pass
print(a)
x = a
print(x)
# 结论
# a方法地址给了 x
# 两个地址都是 a方法
print("---------------------------------------")
def log_track(func):
def wapper(*args, **kwargs):
print(func.__name__)
func(*args, **kwargs)
return wapper
def hello2():
pass
@log_track
def hello():
print("hello")
print(hello)
hello = wapper = log_track(hello) # 和 @log_track效果一样
print(hello)
print(hello2.__name__)
print(hello.__name__)
# 结论
# hello指针指向的hello函数地址进入到wapper作用域中，返回的wapper函数地址给 hello
print("---------------------------------------")
# 带参数的装饰器
def user_loggin(level):
print(level)
def decoration(func):
print(func.__name__)
def wrapper(*args,**kwargs):
print(func.__name__)
func(*args,**kwargs)
print("return wrapper")
return wrapper
print("return decoration")
return decoration
def foo():
return "foo"
func = decoration = user_loggin(level="debug")
print(func)
print("func.__name__ >>>>> ",func.__name__)
print("######################")
func = wrapper = user_loggin(level="debug")(foo)
print(func)
print("func.__name__ >>>>>",func.__name__)
print("######################")
@user_loggin(level="debug")
def foo2():
print("fool")
# 总结
# 带参数的装饰器比不带参数的装饰器多一层，需先解压出装饰器
print("---------------------------------------")
# 类装饰器
class Foo():
def __init__(self,func):
self.__func=func
def __call__(self, *args, **kwargs):
print("before call")
self.__func(*args,**kwargs)
print("after call")
return self.__func
def test():
print("test")
foo_obj=Foo(test)
print(foo_obj)
print("__call__",foo_obj())
print("######################")
print("__call__",foo_obj.__call__())
print("######################")
@Foo
def test1():
print("test1")
test1()
# 总结
# 类装饰器 实质是将 类的__call__地址 负值给要装饰的函数 test1=Foo(test1).__call__
print("---------------------------------------")
##
## 可以发现 需要被装饰的函数的 docstring、__name__ 被装饰器替代了
## 所以引出 functools.wraps，wraps本身也是一个装饰器，它能把原函数的元信息拷贝到装饰器函数中
##
from functools import wraps
def logged(func):
#func=decoration=wraps(func)(with_logging)
#wraps(func)解压并调用类装饰器
#func=partial().__call__
#update_wapper 将with_loggin 的某些参数负值给f return 的 with_logging 变为 f
@wraps(func)
def with_logging(*args, **kwargs):
print(func.__name__ + " was called")
return func(*args, **kwargs)
return with_logging
@logged
def f(x):
"""does some math"""
return x + x * x
print(f.__name__ ) # prints 'f'
print(f.__doc__ ) # prints 'does some math1'
|