我有一个由装饰器转移变量insurance_mode的问题。我将通过以下装饰器语句来实现:

@execute_complete_reservation(True)
def test_booking_gta_object(self):
    self.test_select_gta_object()

但不幸的是,这种说法并不管用。也许也许有更好的办法来解决这个问题。

def execute_complete_reservation(test_case,insurance_mode):
    def inner_function(self,*args,**kwargs):
        self.test_create_qsf_query()
        test_case(self,*args,**kwargs)
        self.test_select_room_option()
        if insurance_mode:
            self.test_accept_insurance_crosseling()
        else:
            self.test_decline_insurance_crosseling()
        self.test_configure_pax_details()
        self.test_configure_payer_details

    return inner_function

当前回答

在我的实例中,我决定通过一行lambda来解决这个问题,以创建一个新的decorator函数:

def finished_message(function, message="Finished!"):

    def wrapper(*args, **kwargs):
        output = function(*args,**kwargs)
        print(message)
        return output

    return wrapper

@finished_message
def func():
    pass

my_finished_message = lambda f: finished_message(f, "All Done!")

@my_finished_message
def my_func():
    pass

if __name__ == '__main__':
    func()
    my_func()

执行时,输出:

Finished!
All Done!

也许不像其他解决方案那样可扩展,但对我来说是可行的。

其他回答

我猜你的问题是把参数传递给你的装饰师。这有点棘手,不简单。

下面是一个如何做到这一点的例子:

class MyDec(object):
    def __init__(self,flag):
        self.flag = flag
    def __call__(self, original_func):
        decorator_self = self
        def wrappee( *args, **kwargs):
            print 'in decorator before wrapee with flag ',decorator_self.flag
            original_func(*args,**kwargs)
            print 'in decorator after wrapee with flag ',decorator_self.flag
        return wrappee

@MyDec('foo de fa fa')
def bar(a,b,c):
    print 'in bar',a,b,c

bar('x','y','z')

打印:

in decorator before wrapee with flag  foo de fa fa
in bar x y z
in decorator after wrapee with flag  foo de fa fa

详见Bruce Eckel的文章。

定义这个decoratorize函数来生成定制的decorator函数:

def decoratorize(FUN, **kw):
    def foo(*args, **kws):
        return FUN(*args, **kws, **kw)
    return foo

可以这样用:

    @decoratorize(FUN, arg1 = , arg2 = , ...)
    def bar(...):
        ...

如果函数和装饰器都必须接受参数,可以采用下面的方法。

例如,有一个名为decorator1的装饰器,它接受一个参数

@decorator1(5)
def func1(arg1, arg2):
    print (arg1, arg2)

func1(1, 2)

现在,如果decorator1参数必须是动态的,或者在调用函数时传递,

def func1(arg1, arg2):
    print (arg1, arg2)


a = 1
b = 2
seconds = 10

decorator1(seconds)(func1)(a, b)

在上面的代码中

Seconds是decorator1的参数 A b是func1的参数

下面是一个使用带有参数的装饰器的Flask示例。假设我们有一个路由'/user/name',我们想要映射到他的主页。

def matchR(dirPath):
    def decorator(func):
        def wrapper(msg):
            if dirPath[0:6] == '/user/':
                print(f"User route '{dirPath}' match, calling func {func}")
                name = dirPath[6:]
                return func(msg2=name, msg3=msg)
            else:
                print(f"Input dirPath '{dirPath}' does not match route '/user/'")
                return
        return  wrapper
    return decorator

#@matchR('/Morgan_Hills')
@matchR('/user/Morgan_Hills')
def home(**kwMsgs):
    for arg in kwMsgs:
        if arg == 'msg2':
            print(f"In home({arg}): Hello {kwMsgs[arg]}, welcome home!")
        if arg == 'msg3':
            print(f"In home({arg}): {kwMsgs[arg]}")

home('This is your profile rendered as in index.html.')

输出:

User route '/user/Morgan_Hills' match, calling func <function home at 0x000001DD5FDCD310>
In home(msg2): Hello Morgan_Hills, welcome home!
In home(msg3): This is your profile rendered as in index.html.

上面的回答很棒。这个例子还演示了@wraps,它从原始函数中获取文档字符串和函数名,并将其应用于新的包装版本:

from functools import wraps

def decorator_func_with_args(arg1, arg2):
    def decorator(f):
        @wraps(f)
        def wrapper(*args, **kwargs):
            print("Before orginal function with decorator args:", arg1, arg2)
            result = f(*args, **kwargs)
            print("Ran after the orginal function")
            return result
        return wrapper
    return decorator

@decorator_func_with_args("foo", "bar")
def hello(name):
    """A function which prints a greeting to the name provided.
    """
    print('hello ', name)
    return 42

print("Starting script..")
x = hello('Bob')
print("The value of x is:", x)
print("The wrapped functions docstring is:", hello.__doc__)
print("The wrapped functions name is:", hello.__name__)

打印:

Starting script..
Before orginal function with decorator args: foo bar
hello  Bob
Ran after the orginal function
The value of x is: 42
The wrapped functions docstring is: A function which prints a greeting to the name provided.
The wrapped functions name is: hello