Decorator (a)

Decorator

开放封闭原则:
    1.拓展是开放的(增加新功能)
    2.修改源码是封闭的(修改已经实现的功能)
装饰器:
    用来装饰的工具
    在不改变源代码及调用方式的基础上额外增加新的功能
    
版本一

import time
start_time = time.time()
def func():
    time.sleep(2)      #睡眠,模拟网络延时
    print("我要飞")
func()
print(time.time() - start_time)

start_time = time.time()
def foo():
    time.sleep(3)
    print("我是小明,我飞的比你高")
foo()
print(time.time() - start_time)

版本二

import time
def times(f):
    start_time = time.time()
    f()
    print(time.time() - start_time)
def foo():
    time.sleep(3)
    print("我是小明,我飞的比你高")
def func():
    time.sleep(1)
    print("我是小刚,我飞不起来")
s = func
func = times
func(s)

s = foo
foo = times
foo(s)


版本三(初识版装饰器)

import time
def times(f):
    def inner():
        start_time = time.time()
        f()
        print(time.time() - start_time)
    return inner
def foo():
    time.sleep(1)
    print("我要飞")
foo = times(foo)
foo()


版本四(第四版装饰器)

def wrapper():
    def inner():
        print(1)
    return inner
wrapper()

def wrapper(f):
    def inner():
        print(f)
    return inner
wrapper("alex")


def wrapper(f):
    def inner():
        f()
     return inner
def func():
    print("这是func函数")
func = wrapper(func)
func()


def wrapper(f):
    def inner(*args,**kwargs):
        f(*args,**kwargs)
    return inner
def func(*args,**kwargs):
    print(f"这是{args}函数")
func = wrapper(func)
func("alex","wusir")

low版:
import time
def wrapper(f):
    def inner(*args,**kwargs):
        #被装饰前#
        start_time = time.time()
        f(*args,**kwargs)
        print(time.time() - start_time)
        #被装时后#
    return inner
def func(*args.**kwargs):
    print(f"这是{args}函数")
    time.sleep(2)
func = wrapper(func)
func("alex","wusir")

高级:
import time
def wrapper(f):
    def inner(*args,**kwargs):
        #被装饰前#
        start_time = time.time()
        f(*args,**kwargs)
        print(time.time() - start_time)
        #被装饰后#
    return inner
@wrapper
def func(*args,**kwargs):
    print(f"这是{args}函数a")
    time.sleep(2)
@wrapper
def foo(*args,**kwargs):
    print(f"这是{args}函数b")
    time.sleep(3)
func("alex","wusir")
foo("alex","wusir")


语法糖
语法糖必须放在被装饰的函数正上方

import time
def wrapper(f):
    def inner(*args,**kwargs):
        #被装饰前#
        start_time= time.time()
        ret = f(*args,**kwargs)
        print(time.time() - start_time)
        #被装饰后#
        return retre
    return inner
@wrapper
def func(*args,**kwargs):
    print(f"这是{args}函数")
    time.sleep(2)
    return "alex"
print(func())