[英]Python how to get __qualname__ of method wrapped with property.setter
我有一个实例属性,我使用 Python 的property
装饰器创建了一个属性。
然后我使用装饰器@property_name.setter
为属性创建了一个 setter。
如何获得用@property.setter
修饰的原始方法定义的__qualname__
?
我看过的地方
property
使用@functools.wraps()
property
实际上是一个descriptor
__get__
,但我无法弄清楚语法示例代码
这是用Python 3.6
编写的。
#!/usr/bin/env python3
def print_qualname():
"""Wraps a method, printing its qualified name."""
def print_qualname_decorator(func):
# print(f"func = {func} and dir(): {dir(func)}")
if hasattr(func, "__qualname__"):
print(f"Qualified name = {func.__qualname__}.")
else:
print("Doesn't have qualified name.")
return print_qualname_decorator
class SomeClass:
def __init__(self):
self._some_attr = 0
self._another_attr = 0
@property
def some_attr(self) -> int:
return self._some_attr
@print_qualname()
@some_attr.setter
def some_attr(self, val: int) -> None:
self._some_attr = val
@print_qualname()
def get_another_attr(self) -> int:
return self._another_attr
输出:
Doesn't have qualified name.
Qualified name = SomeClass.get_another_attr.
我怎样才能获得__qualname__
为some_attr
从里面print_qualname
装饰? 换句话说,如何让SomeClass.some_attr
输出?
您可以翻转 setter 装饰器的顺序。 注意我已经调整了print_qualname_decorator
来调用底层函数并返回它(否则 setter 将不会执行)。
from functools import wraps
def print_qualname(func):
"""Wraps a method, printing its qualified name."""
@wraps(func)
def print_qualname_decorator(*args):
if hasattr(func, "__qualname__"):
print(f"Qualified name = {func.__qualname__}.")
else:
print("Doesn't have qualified name.")
return func(*args)
return print_qualname_decorator
class SomeClass:
def __init__(self):
self._some_attr = 0
self._another_attr = 0
@property
def some_attr(self) -> int:
return self._some_attr
@some_attr.setter
@print_qualname
def some_attr(self, val: int) -> None:
self._some_attr = val
@print_qualname
def get_another_attr(self) -> int:
return self._another_attr
用
In [46]: foo = SomeClass()
In [47]: foo.get_another_attr()
Qualified name = SomeClass.get_another_attr.
Out[47]: 0
In [48]: foo.some_attr = 5
Qualified name = SomeClass.some_attr.
In [49]: foo._some_attr
Out[49]: 5
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