class _MethodDecoratorAdaptor(object):
def __init__(self, decorator, func):
self.decorator = decorator
self.func = func
def __call__(self, *args, **kwargs):
return self.decorator(self.func)(*args, **kwargs)
def __get__(self, instance, owner):
return self.decorator(self.func.__get__(instance, owner))
def auto_adapt_to_methods(decorator):
"""Allows you to use the same decorator on methods and functions,
hiding the self argument from the decorator."""
def adapt(func):
return _MethodDecoratorAdaptor(decorator, func)
return adapt
这样，您可以使装饰器自动适应其使用条件。
def allowed(*allowed_methods):
@auto_adapt_to_methods
def wrapper(func):
def wrapped(request):
if request not in allowed_methods:
raise ValueError("Invalid method %s" % request)
return func(request)
return wrapped
return wrapper
请注意，包装函数在所有函数调用中都被调用，因此不要在其中做任何昂贵的事情。
装饰器的用法：
class Foo(object):
@allowed('GET', 'POST')
def do(self, request):
print "Request %s on %s" % (request, self)
@allowed('GET')
def do(request):
print "Plain request %s" % request
Foo().do('GET') # Works
Foo().do('POST') # Raises
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