Python 如何拦截实例方法调用?
我在下面的类Python 如何拦截实例方法调用?,python,function,call,instance,getattr,Python,Function,Call,Instance,Getattr,我在下面的类MyWrapper中寻找拦截实例方法调用的方法: class SomeClass1: def a1(self): self.internal_z() return "a1" def a2(self): return "a2" def internal_z(self): return "z" class SomeClass2(SomeClass1): pass class MyWrapp
MyWrapper
中寻找拦截实例方法调用的方法:
class SomeClass1:
def a1(self):
self.internal_z()
return "a1"
def a2(self):
return "a2"
def internal_z(self):
return "z"
class SomeClass2(SomeClass1):
pass
class MyWrapper(SomeClass2):
# def INTERCEPT_ALL_FUNCTION_CALLS():
# result = Call_Original_Function()
# self.str += result
# return result
def __init__(self):
self.str = ''
def getFinalResult(self):
return self.str
x = MyWrapper()
x.a1()
x.a2()
我想截获通过包装器类进行的所有函数调用。在我的包装器类中,我希望跟踪所有结果字符串
result = x.getFinalResult()
print result == 'a1a2'
一些快速而肮脏的代码:
class Wrapper:
def __init__(self, obj):
self.obj = obj
self.callable_results = []
def __getattr__(self, attr):
print("Getting {0}.{1}".format(type(self.obj).__name__, attr))
ret = getattr(self.obj, attr)
if hasattr(ret, "__call__"):
return self.FunctionWrapper(self, ret)
return ret
class FunctionWrapper:
def __init__(self, parent, callable):
self.parent = parent
self.callable = callable
def __call__(self, *args, **kwargs):
print("Calling {0}.{1}".format(
type(self.parent.obj).__name__, self.callable.__name__))
ret = self.callable(*args, **kwargs)
self.parent.callable_results.append(ret)
return ret
class A:
def __init__(self, val): self.val = val
def getval(self): return self.val
w = Wrapper(A(10))
print(w.val)
w.getval()
print(w.callable_results)
可能不彻底,但我想这可能是一个不错的起点。您可以在实例化时使用装饰程序包装您的方法:
#!/usr/bin/env python
import inspect
def log(func):
def _logged(*args, **kw):
print "[LD] func", func.__name__, "called with:", args, kw
result = func(*args, **kw)
print "[LD] func", func.__name__, "returned:", result
return result
return _logged
class A(object):
def __init__(self):
for x in inspect.getmembers(self, (inspect.ismethod)):
if not x[0].startswith('__'):
setattr(self, x[0], log(getattr(self, x[0])))
def hello(self):
print "Hello"
def bye(self):
print "Bye"
return 0
现在,如果您呼叫hello
或bye
,呼叫首先通过log
:
a = A()
a.hello()
a.bye()
# [LD] func hello called with: () {}
# Hello
# [LD] func hello returned: None
# [LD] func bye called with: () {}
# Bye
# [LD] func bye returned: 0
你想做的事和我的很相似。 您应该以相反的顺序使用示例代码,我的意思是创建一个类来记录方法调用的返回值,并使您想要查看的类从中继承。 这样的话
class RetValWatcher(object):
def __init__(self):
self.retvals = []
def __getattribute__(self, name):
attr = super(RetValWatcher, self).__getattribute__(name)
if callable(attr):
def wrapped(*args, **kwargs):
retval = attr(*args, **kwargs)
self.retvals.append(retval)
return retval
return wrapped
else:
return attr
def getFinalRestult(self):
return ''.join(self.retvals)
class MyClass(RetValWatcher):
def a(self):
self.internal_z()
return 'a1'
def b(self):
return 'b1'
def internal_z(self):
return 'z'
x = MyClass()
x.a()
x.b()
print x.getFinalResult()
#'za1b1'
通过一些微小的更改,此方法还允许您记录所有RetValWatcher实例的返回值
编辑:添加了奇点评论建议的更改
Edit2:忘记处理attr不是方法的情况(再次出现thx奇点)很高兴知道-不客气。请将答案标记为“已接受”:+1,我更喜欢这种方法,但我有一些意见:1)用
self.retvals=[]
替换retvals=[]
,2)在OPx的情况下,getFinalResult()
将返回za1a2而不是a1a2,3)我认为最好使用inspect.ismethod
或callable(attr)
而不是hasattr(attr,'.\u call'.\uu')
。缺少的“self”只是一个疏忽,但其他两点你是对的。编辑;)啊,再次抱歉;您忘记了else:if callable(attr):
的返回attr
,因为您不想模糊属性调用:)输入错误:def getfinalresttult(self):