python 阿狸的进阶之路(4)

装饰器

 

#1、开放封闭原则：对扩展开放，对修改是封闭
#2、装饰器：装饰它人的，器指的是任意可调用对象，现在的场景装饰器-》函数，被装饰的对象也是-》函数
#原则：1、不修改被装饰对象的源代码 2、不修改被装饰对象的调用方式
#装饰器的目的：在遵循1,2的前提下为被装饰对象添加上新功能

 （1）无参数类型

import time
def outer(func):def inner():time.sleep(1)print("hello")func()return inner

def bar():print('world')

 （2）有参数类型

# 有参装饰器
import timedef auth2(engine='file'):def auth(func): # func=indexdef inner(*args,**kwargs):if engine == 'file':name=input('name>>: ').strip()password=input('password>>: ').strip()if name == 'egon' and password == '123':print('login successful')return func(*args,**kwargs)else:print('login err')elif engine == 'mysql':print('mysql auth')elif engine == 'ldap':print('ldap auth')else:print('engin not exists')return innerreturn auth@auth2(engine='mysql') #@auth #index=auth(index) #index=inner
def index(name):time.sleep(1)print('welecome %s to index' %name)return 1111res=index('egon') #res=inner('egon')
print(res)

（3）并列装饰器

import time
def timmer(func):def inner(*args,**kwargs):start=time.time()res=func(*args,**kwargs)stop=time.time()print('run time is %s' %(stop-start))return resreturn innerdef auth2(engine='file'):def auth(func): # func=indexdef inner(*args,**kwargs):    # 一致if engine == 'file':name=input('name>>: ').strip()password=input('password>>: ').strip()if name == 'egon' and password == '123':print('login successful')res = func(*args,**kwargs) #一致return reselse:print('login err')elif engine == 'mysql':print('mysql auth')elif engine == 'ldap':print('ldap auth')else:print('engin not exists')return innerreturn auth@auth2(engine='file')
@timmer
def index(name):time.sleep(1)print('welecome %s to index' %name)return 1111res=index('egon')
print(res)

（4）

from functools import wraps
import time
def timmer(func):@wraps(func)def inner(*args,**kwargs):start=time.time()res=func(*args,**kwargs)stop=time.time()print('run time is %s' %(stop-start))return res# inner.__doc__=func.__doc__# inner.__name__=func.__name__return inner@timmer
def index(name): #index=inner'''index 函数。。。。。'''time.sleep(1)print('welecome %s to index' %name)return 1111res=index('egon')
print(res)print(help(index))