[英]Decorator/wrapper: How to deal with arguments after positional/keyword args are all assigned to wrapped function's parameters?
I'm wondering if there's a way in Python for a wrapper to get access to a function's arguments after they've already been resolved into parameters. 我想知道在Python中是否有一种方法可以让包装器在将函数的参数解析为参数后对其进行访问。 So for instance, I'd like to wrap two functions that have different (numbers of) parameters:
因此,例如,我想包装两个具有不同(数量)参数的函数:
def fn_1(a, b=None, config=None):
...
def fn_2(b=None, config=None):
...
I'd like for my wrapper to see if config
has a value and, if not, to load it from somewhere else: 我想对我的包装,看是否
config
并具有价值,如果没有,从别的地方加载它:
class with_config(object):
def __init__(self, f):
self.f = f
def __call__(self, *args, **kwargs):
if config not in kwargs:
kwargs[config] = load_config_from_some_default_location()
but I don't know how to determine if config
has been passed positionally, as its position in the args
list can vary from function to function. 但我不知道如何确定
config
是否已按位置传递,因为它在args
列表中的位置因函数而异。
If I could get ahold of the arguments after the positional ones have been given names according to the parameters (eg first positional assigned to a
, second to b
, third to config
) I'd be A-OK. 如果我已经根据参数给位置参数指定了名称(例如,将第一个位置分配给
a
,将第二个位置分配给b
,第三个位置分配给config
),然后可以保留这些参数,那么我会答应。
The situation is slightly more complex than this but I think this gets my question across. 情况比这要复杂得多,但是我认为这使我的问题更容易理解。
Any tips? 有小费吗?
This may help you: 这可以帮助您:
import inspect
def func(a, b=None, config=None):
args, _, _, values = inspect.getargvalues(inspect.currentframe())
print args # prints 'a', 'b', 'config'
print values # prints {'a':12, 'b':None, 'config':None}
if values['config'] == None:
# Load config from somewhere else
if __name__ == '__main__':
func(12)
我终于从Nadia Alramli那里得到了这个解决方案 :
class with_config(object): def
__init__
(self, f): self.f = f def __call__
(self, *args, **kwargs): kwargs.update(dict(zip(self.f.func_code.co_varnames, args))) if config not in kwargs: kwargs[config] = load_config_from_some_default_location() return self.f(**kwargs)
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