Question

我有一个需要调用analyze方法的类实例。构造函数使用此类消息接收请求对象

{ “信息”：{ “属性”：{ “MESSAGE_ID”： “2aj78h98-2112-4637-76h1-09ec727933bb” “主题”：“MyTopic” “版本”：1 }， “data”：“{”id“：123541234}” } }

my_model = MyModel(request)
my_model.analyse(data)

MyModel类的结构是：

import importlib


class MyModel(object):

    def __init__(self, req):

        """
        From the request, extract the topic and dynamically create is    instance
        """
        try:
            self.req = req
            classname = self.req.topic # in this example: MyTopic
            classpath = 'foo.bar'
            module = importlib.import_module(classpath)
            self.some_object = getattr(module, classname)
        except Exception as e:
            raise Exception(e.message)

    def analyse(self):
        data = self.req.data
        # self.some_object is an instance of foo.bar.MyTopic
        self.some_object.analyse(data)

以下是MyTopic类的结构：

class MyTopic(TopicBase):

    def __init__(self):
        super(MyTopic, self).__init__()
        self.retreive_mode = 'api'

    def _retreive_from_db(self):
        print 'in db'

    def _retreive_from_datawarehouse(self):
        print 'in datawarehouse'

    def _retreive_from_api(self):
       print 'in api

及其父类：

from abc import ABCMeta, abstractmethod

class TopicBase(object):
__metaclass__ = ABCMeta

    def __init__(self, *args, **kwargs):
        pass

    def analyse(self, data):
        """
        Base on the class configuration, call the proper retreive method
        """

        def func_not_found():  # just in case we dont have the method
            raise NotImplementedError

        func_name = '_retreive_from_' + self.retreive_mode
        func = getattr(self, func_name, func_not_found)
        func(data)

    @abstractmethod
    def _retreive_from_db(self):
        pass

    @abstractmethod
    def _retreive_from_datawarehouse(self):
        pass

    @abstractmethod
    def _retreive_from_api(self):
        pass

当调用my_model.analyse（data）时，我收到错误：

TypeError: unbound method analyse() must be called with MyTopic instance as first argument (got dict instance instead)

my_model已经是MyTopic的一个实例。所以，如果我尝试my_model.analyse（my_model，data），我收到错误：

TypeError: unbound method analyse() must be called with MyTopic instance as first argument (got ABCMeta instance instead)

任何想法??

Answer 1

此

self.some_object = getattr(module, classname)

将self.some_object设置为一个类（不是该类的实例），这意味着当MyModel.analyse()调用时

self.some_object.analyse(data)

它正在呼叫SomeClass.analyse(data)而不是SomeClass().analyse(data)。

Python：在抽象类中动态调用函数

1 个答案: