我有一个 Python 装饰器，用于将函数/方法标记为已弃用。它的工作足够，但我希望它更好。具体来说，我想让它做的是能够将调用的确切行号告诉已弃用的函数。这样一来，就不必通过 grep 查找源代码了；相反，警告将直接指向它。 (这并不是说有人无论如何都不会 grep 遍历代码来寻找其他调用已弃用函数的地方，但恕我直言，他们不应该为了响应这样的警告而这样做)。
class deprecated(object):
'''This class implements the deprecated decorator.
This decorator is used to mark a function or a class as
deprecated. A message indicating why it is deprecated (and what
to use instead) must be provided. Also, a version number
indicating when the function or class was deprecated must _also_
be provided.
Optionally, a third parameter may be passed that indicates when
the deprecated functionality will actually be removed.'''
def __init__(self, message, version, to_be_removed_in_version = None):
self._message = message
self._version = version
self._removal_version = to_be_removed_in_version
return
def __call__(self, func):
def wrapper(*args, **kwargs):
import warnings
import inspect
frame = inspect.currentframe().f_back
where = 'Called from {0} somewhere after line {1}.'
where = where.format(frame.f_code.co_filename,
frame.f_code.co_firstlineno)
msg = 'Call to deprecated function {0} (since {1}{2}) {3}'
if self._removal_version is not None:
removal = ', scheduled for removal by version {0}'
removal = removal.format(self._removal_version)
msg = msg.format(func.__name__, self._version,
removal, where)
warnings.warn_explicit(msg, category = DeprecationWarning,
filename = func.func_code.co_filename,
lineno = func.func_code.co_firstlineno + 1)
return func(*args, **kwargs)
wrapper.__name__ = func.__name__
wrapper.__doc__ = func.__doc__
wrapper.__dict__.update(func.__dict__)
return wrapper
请您参考如下方法:
你不需要那么多东西:
from functools import wraps
import warnings
def deprecated(message, newfunc):
def _deprecated(func):
@wraps(func)
def _wrapped(*args, **kwds):
warnings.warn(message + ', ' + newfunc,
DeprecationWarning, stacklevel=2)
return func(*args, **kwds)
return _wrapped
return _deprecated
就是这样!检查一下:
@deprecated("function foo is deprecated", "use bar instead")
def foo(bar):
print 'Hello', bar
foo('World')
我明白了
teste.py:17: DeprecationWarning: function foo is deprecated, use bar instead
foo('World')
Hello World
另一个例子:
class Foo(object):
@deprecated("method bar is deprecated", "use baz instead")
def bar(self, baz):
print 'Goodbye', baz
f = Foo()
f.bar('World')
我得到:
teste.py:25: DeprecationWarning: method bar is deprecated, use baz instead
f.bar('World')
Goodbye World
secret 是 warnings.warn 的 stacklevel 参数。 docs说:
The stacklevel argument can be used by wrapper functions written in Python, (...) makes the warning refer to deprecation()‘s caller, rather than to the source of deprecation() itself (since the latter would defeat the purpose of the warning message).
