python 中面向切面编程AOP和装饰器

# 装饰器就是把其他函数作为参数的函数
def my_new_decorator(a_function_to_decorate):

    # 在函数里面,装饰器在运行中定义函数: 包装.
    # 这个函数将被包装在原始函数的外面,所以可以在原始函数之前和之后执行其他代码..
    def the_wrapper_function():

        # 把要在原始函数被调用前的代码放在这里
        print "Before the function runs"

        # 调用原始函数(用括号)
        a_function_to_decorate()

        # 把要在原始函数调用后的代码放在这里
        print "After the function runs"

    # 在这里"a_function_to_decorate" 函数永远不会被执行
    # 在这里返回刚才包装过的函数
    # 在包装函数里包含要在原始函数前后执行的代码.
    return the_wrapper_function

# 加入你建了个函数,不想修改了
def a_stand_alone_function():
    print "I am a stand alone function, don't you dare modify me"

a_stand_alone_function()
#输出: I am a stand alone function, don't you dare modify me

# 现在,你可以装饰它来增加它的功能
# 把它传递给装饰器,它就会返回一个被包装过的函数.

a_function_decorated = my_new_decorator(a_stand_alone_function)
# 执行
a_function_decorated()
#输出s:
#Before the function runs
#I am a stand alone function, don't you dare modify me
#After the function runs

@my_new_decorator
def another_stand_alone_function():
    print "Leave me alone"

another_stand_alone_function()
#输出:
#Before the function runs
#Leave me alone
#After the function runs

another_stand_alone_function = my_new_decorator(another_stand_alone_function)

def a_decorator_passing_arguments(function_to_decorate):
    def a_wrapper_accepting_arguments(arg1, arg2):
        print "I got args! Look:", arg1, arg2
        function_to_decorate(arg1, arg2)
    return a_wrapper_accepting_arguments

# 当你调用装饰器返回的函数时,也就调用了包装器,把参数传入包装器里,
# 它将把参数传递给被装饰的函数里.

@a_decorator_passing_arguments
def print_full_name(first_name, last_name):
    print "My name is", first_name, last_name

print_full_name("Peter", "Venkman")
# 输出:
#I got args! Look: Peter Venkman
#My name is Peter Venkman

# 装饰器就是一个'平常不过'的函数
def my_decorator(func):
    print "I am an ordinary function"
    def wrapper():
        print "I am function returned by the decorator"
        func()
    return wrapper

# 因此你可以不用"@"也可以调用他

def lazy_function():
    print "zzzzzzzz"

decorated_function = my_decorator(lazy_function)
#输出: I am an ordinary function

# 之所以输出 "I am an ordinary function"是因为你调用了函数,
# 并非什么魔法.

@my_decorator
def lazy_function():
    print "zzzzzzzz"

#输出: I am an ordinary function

def decorator_maker_with_arguments(decorator_arg1, decorator_arg2):

    print "I make decorators! And I accept arguments:", decorator_arg1, decorator_arg2

    def my_decorator(func):
        # 这里传递参数的能力是借鉴了 closures.
        # 如果对closures感到困惑可以看看下面这个:
        # http://stackoverflow.com/questions/13857/can-you-explain-closures-as-they-relate-to-python
        print "I am the decorator. Somehow you passed me arguments:", decorator_arg1, decorator_arg2

        # 不要忘了装饰器参数和函数参数!
        def wrapped(function_arg1, function_arg2) :
            print ("I am the wrapper around the decorated function.\n"
                  "I can access all the variables\n"
                  "\t- from the decorator: {0} {1}\n"
                  "\t- from the function call: {2} {3}\n"
                  "Then I can pass them to the decorated function"
                  .format(decorator_arg1, decorator_arg2,
                          function_arg1, function_arg2))
            return func(function_arg1, function_arg2)

        return wrapped

    return my_decorator

@decorator_maker_with_arguments("Leonard", "Sheldon")
def decorated_function_with_arguments(function_arg1, function_arg2):
    print ("I am the decorated function and only knows about my arguments: {0}"
           " {1}".format(function_arg1, function_arg2))

decorated_function_with_arguments("Rajesh", "Howard")
#输出:
#I make decorators! And I accept arguments: Leonard Sheldon
#I am the decorator. Somehow you passed me arguments: Leonard Sheldon
#I am the wrapper around the decorated function.
#I can access all the variables
#   - from the decorator: Leonard Sheldon
#   - from the function call: Rajesh Howard
#Then I can pass them to the decorated function
#I am the decorated function and only knows about my arguments: Rajesh Howard

def addTips(fun):
    def wrap(*arg,**kwargs):
        print("this is oper before")
        result = fun(*arg,**kwargs)
        #return result
        print("this is oper after")
        return result
    return wrap
@addTips
def add():
    print("进行添加的操作")
    
add()

this is oper before
进行添加的操作
this is oper after

@addTips
def add1(x,y):
    print(x+y)
add1(2,6)

this is oper before
8
this is oper after

@addTips
def add2(x,y):
    return x+y

print(add2(2,3))

this is oper before
this is oper after
5

def addTips(i):
    def wrap1(fun):
        def wrap(*arg,**kwargs):
            print("this is oper before")
            result = 0
            if i > 10:
                result = fun(*arg,**kwargs)
            else:
                print("you not have any auth")
            #return result
            print("this is oper after")
            return result
        return wrap
    return wrap1

@addTips(11)
def add(x,y):
    print(x+y)
    
add(2,3)

this is oper before
5
this is oper after