装饰器

函数修饰器

修饰带有返回值的函数

修改返回值:

def w_test(func):
    def inner():
        print('w_test inner called start')
        str = func()
        print('w_test inner called end')
        return str.lower()
    return inner
@w_test
def test():
    print('this is test fun')
    return 'HELLO'
ret = test()
print('ret value is %s' % ret)

装饰器带参数，函数不带参数:

def func_args(pre='xiaoqiang'):
    def w_test_log(func):
        def inner():
            print('...记录日志...visitor is %s' % pre)
            func()
        return inner
    return w_test_log
# 带有参数的装饰器能够起到在运行时，有不同的功能
# 先执行func_args('wangcai')，返回w_test_log函数的引用
# @w_test_log
# 使用@w_test_log对test_log进行装饰
@func_args('wangcai')
def test_log():
    print('this is test log')
test_log()

修饰类

def register():

    def _mock_wrapper(_class):
        return _class
    return _mock_wrapper


class A:
    def __init__(self):
        pass

    def q(self):
        print(333)

    @classmethod
    def t(cls):
        print(1111)


@register()  # 必须带括号，不带括号是当作函数使用
class B(A):
    def t2(self):
        print(2222)

用类方法的装饰器

class Docker:
    subcommands = []

    @classmethod
    def subcommand(cls, sub_class):
        cls.subcommands.append(sub_class)
        del sub_class

@Docker.subcommand
class Search:
    ...