Python3.5装饰器原理及应用实例详解

import time
#统计函数运行时间的砖装饰器
def timmer(func):
  def warpper(*args,**kwargs):
    strat_time = time.time()
    func()
    stop_time = time.time()
    print("the func run time is %s" %(stop_time-strat_time))
  return warpper
@timmer
def test1():
  time.sleep(3)
  print("in the test1")
test1()
 

def bar():
  print("in the bar")
def foo():
  print("in the foo")
  bar()
foo()
#python为解释执行，函数foo在调用前已经声明了bar和foo，所以bar和foo无顺序之分
def foo():
  print("in the foo")
  bar()
def bar():
  print("in the bar")
foo()

def bar():
  print("in the bar")
def test1(func):
  print(func)  #打印门牌号，即内存地址
  func()
test1(bar)   #门牌号func=bar

import time
def bar():
  time.sleep(3)
  print("in the bar")
#test2在不修改被修饰函数bar的代码时添加了附加的及时功能
def test2(func):
  start_time = time.time()
  func()   #run bar
  stop_time = time.time()
  print("the func run time is %s " %(stop_time-start_time))
#调用方式发生改变，不能像原来的方法去调用被修饰的函数（所以不能实现装饰器的功能）
test2(bar)
#bar()

import time
def bar():
   time.sleep(3)
   print("in the bar")
def test3(func):
  print(func)
  return func
bar = test3(bar)
bar()  #run bar

#函数嵌套
def foo():
  print("in the foo")
  def bar():  #bar函数具有局部变量的特性，不能在外部调用,只能在内部调用
    print("in the bar")
  bar()
foo()

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
#模拟网站，访问页面和部分需要登录的页面
import timer
user,passwd = "liu","liu123"
def auth(func):
  def wrapper(*args,**kwargs):
    username = input("Username:").strip()
    password = input("Password:").strip()
    if username == user and password == passwd:
      print("\033[32;1mUser has passed authentication!\033[0m")
      res = func(*args,**kwargs)
      print("-----after authentication---")
      return res
    else:
      exit("\033[31;1mInvalid username or password!\033[0m")
  return wrapper
def index():
  print("welcome to index page!")
@auth
def home():
  print("welcome to index home!")
  return "from home"
@auth
def bbs():
  print("welcome to index bbs!")
#函数调用
index()
print(home())
bbs()
 

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:ZhengzhengLiu
#模拟网站，访问页面和部分需要登录的页面，多种认证方式
import timer
user,passwd = "liu","liu123"
def auth(auth_type):
  print("auth func:",auth_type)
  def outer_wrapper(func):
    def wrapper(*args, **kwargs):
      print("wrapper func args:",*args, **kwargs)
      if auth_type == "local":
        username = input("Username:").strip()
        password = input("Password:").strip()
        if username == user and password == passwd:
          print("\033[32;1mUser has passed authentication!\033[0m")
          #被装饰的函数中有返回值，装饰器中传入的参数函数要有返回值
          res = func(*args, **kwargs)  #from home
          print("-----after authentication---")
          return res
        else:
          exit("\033[31;1mInvalid username or password!\033[0m")
      elif auth_type == "ldap":
        print("ldap....")
    return wrapper
  return outer_wrapper
def index():
  print("welcome to index page!")
@auth(auth_type="local")    #利用本地登录 home = wrapper()
def home():
  print("welcome to home page!")
  return "from home"
@auth(auth_type="ldap")    #利用远程的ldap登录
def bbs():
  print("welcome to bbs page!")
#函数调用
index()
print(home())   #wrapper()
bbs()