023_decorater

Posted 2021-01-05 liujun5319

#!/usr/bin/env python
# Author:liujun

# The essence of decorator is function which is used to decorate another function.
# The decorator is used to add some additional ability to a function.
# The principle of defining a decorator
    # You can not modify the source code of the function to be decorated
    # You can not change the way calling the function to be decorated


# Functions are alse variables
# Higher-order functions
    # Pass a function as a parameter to another function
    # The function name is included in the return value


# The following code implements adding a functionality to the function,
# but it‘s not a decorator,because it doesn‘t satisfy the other condition
import time
def func():
    time.sleep(1)
    print("in the func")
def decorator(func):
    start_time = time.time()
    func()
    end_time = time.time()
    print("the func run time is %s"%(end_time - start_time))
#decorator(func)




# The following code implements adding functionalty to a function without changing the way to call it
def bar():
    time.sleep(1)
    print("in the bar")

def decorator2(func):
    print(func)
    return func # Just return the address of func

bar = decorator2(bar)
#bar()




# Embeded function
def foo():
    print("in the foo")
    def bar():  # This is a local variable
        print("in the bar")
    bar()
foo()





# Decoretor version 1
# We do not modify the source code and we add the new func to it.
# But we changed the way to call it
def decorator1(func):
    start_time = time.time()
    func()
    end_time = time.time()
    print("the func run time is %s" % (end_time - start_time))

def test1_1():
    time.sleep(1)
    print("in the test1_1")

def test1_2():
    time.sleep(1)
    print("in the test1_2")
decorator1(test1_1)
decorator1(test1_2)



# Decoretor version 2
# We do not modify the source code and not change the way to call it
# But we do not add new func to it
def decorator2(func):
    start_time = time.time()
    return func
    end_time = time.time()
    print("the func run time is %s" % (end_time - start_time))

def test2_1():
    time.sleep(1)
    print("in the test2_1")

def test2_2():
    time.sleep(1)
    print("in the test2_2")
test2_1 = decorator2(test2_1)
test2_2 = decorator2(test2_2)
test2_1()
test2_2()




# Decoretor version 3 : higher-order function + Embed function
def timer(func):
    def deco():
        start_time = time.time()
        func()
        end_time = time.time()
        print("the func run time is %s" % (end_time - start_time))
    return deco
def test3_1():
    time.sleep(1)
    print("in the test3_1")

def test3_2():
    time.sleep(1)
    print("in the test3_2")

test3_1 = timer(test3_1)
test3_2 = timer(test3_2)
test3_1()
test3_2()


# Decoretor version 4 : higher-order function + Embed function + @decoretor
def timer2(func):
    def deco():
        start_time = time.time()
        func()
        end_time = time.time()
        print("the func run time is %s" % (end_time - start_time))
    return deco

@timer2 # @timer2 is identical to test4-1 = timer(test4-1)
def test4_1():
    time.sleep(1)
    print("in the test4_1")

@timer2  # @timer2 is identical to test4-2 = timer(test4-2)
def test4_2():
    time.sleep(1)
    print("in the test4_2")
test4_1()
test4_2()



# Decoretor version 4 : higher-order function + Embed function + @decoretor + parameters
def timer3(func):
    def deco(*args,**kwargs):
        start_time = time.time()
        func(*args,**kwargs)
        end_time = time.time()
        print("the func run time is %s" % (end_time - start_time))
    return deco

@timer3
def test5_1():
    time.sleep(1)
    print("in the test5_1")

@timer3  # @timer2 is identical to test4-2 = timer(test4-2)
def test5_2(name,age):
    time.sleep(1)
    print("in the %s : %s"%(name,age))

test5_1()
test5_2("liujun",28)






#!/usr/bin/env python
# Author:liujun

user = "liujun"
passwd = "123456"

‘‘‘
#version 1
def auth(func):
    def inDecoretor(*args,**kwargs):
        username = input("username:")
        password = input("password:")
        func(*args,**kwargs)
    return inDecoretor

@auth
def home():
    print("this is home")
    #return "from home"

@auth
def bbs():
    print("this is bbs")

‘‘‘


#version 2
def auth(autoType):
    def outDecoretor(func):
        def inDecoretor(*args, **kwargs):
            username = input("username:")
            password = input("password:")
            res = "none"
            if autoType=="home":
                if user == username and passwd == password:
                    res = func(*args, **kwargs)
                else:
                    print("your name or password are wrong")
            else:
                print("bbs can not be allowed here")
            return res
        return inDecoretor
    return outDecoretor

@auth("home")
def home():
    print("this is home")
    return "from home"

@auth("bbs")
def bbs():
    print("this is bbs")

print(home())
bbs()