python wraps decorator

frominspectimportgetmembers, getargspec

fromfunctoolsimportwraps

 

defwraps_decorator(f):

    @wraps(f)

    defwraps_wrapper(*args,**kwargs):

        returnf(*args,**kwargs)

    returnwraps_wrapper

 

classSomeClass(object):

    @wraps_decorator

    defmethod(self, x, y):

        pass

 

obj=SomeClass()

forname, funcingetmembers(obj, predicate=inspect.ismethod):

    print"Member Name: %s"% name

    print"Func Name: %s"% func.func_name

    print"Args: %s"% getargspec(func)[0]

 

classmyDecorator(object):

 

    def__init__(self, fn):

        print"inside myDecorator.__init__()"

        self.fn=fn

 

    def__call__(self):

        self.fn()

        print"inside myDecorator.__call__()"

 

@myDecorator

defaFunction():

    print"inside aFunction()"

 

print"Finished decorating aFunction()"

 

aFunction()







你會發現，即使是你你用了functools的wraps，你在用getargspec時，參數也不見了。

要修正這一問，我們還得用Python的反射來解決，下面是相關的代碼：

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defget_true_argspec(method):     argspec= inspect.getargspec(method)     args= argspec[0]     ifargs andargs[0]=='self':         returnargspec     ifhasattr(method,'__func__'):         method= method.__func__     ifnot hasattr(method, 'func_closure')or method.func_closure is None:         raiseException("No closure for method.")       method= method.func_closure[0].cell_contents     returnget_true_argspec(method)

當然，我相信大多數人的程序都不會去getargspec。所以，用functools的wraps應該夠用了。

class MyApp():

    def __init__(self):

        self.func_map = {}

 

    def register(self, name):

        def func_wrapper(func):

            self.func_map[name] = func

            return func

        return func_wrapper

 

    def call_method(self, name=None):

        func = self.func_map.get(name, None)

        if func is None:

            raise Exception("No function registered against - " + str(name))

        return func()

 

app = MyApp()

 

@app.register('/')

def main_page_func():

    return "This is the main page."

 

@app.register('/next_page')

def next_page_func():

    return "This is the next page."

 

print app.call_method('/')

print app.call_method('/next_page')