有一个叫做 ContextDecorator
的类,你可以创建继承自它的上下文管理器,并像下面这样使用它:
from functools import wraps
from contextlib import ContextDecorator
class MyContext(ContextDecorator):
def __enter__(self):
print('in enter')
return self
def __exit__(self, exc_type, exc_val, exc_tb):
print('in exit')
some_context = MyContext()
@some_context
def foo(x, y):
print(x + y)
foo(5, 3)
然而,我不确定您是否可以将其用于您没有编写的现有内容,或者它是否适用于异步内容,在这种情况下,您可以编写一个类似于以下内容的装饰器:
from functools import wraps
class MyContext:
def __enter__(self):
print('in enter')
return self
def __exit__(self, exc_type, exc_val, exc_tb):
print('in exit')
def context_decorator(context_manager):
def inner(func):
@wraps(func)
def wrapper(*args, **kwargs):
with context_manager:
return func(*args, **kwargs)
return wrapper
return inner
some_context = MyContext()
@context_decorator(some_context)
def foo(x, y):
print(x + y)
foo(5, 3)
in enter
8
in exit
注意,对于类似asyncio.Semephore这样的内容,需要修改代码以在相关位置使用async with
和await