继承一个类而不初始化父类django

Question

我有一个MQTT初始化器类

class Initializer():
def __init__(self):
self.client = mqtt.Client(mqtt_server+str(int(time.time()))) 
self.client.username_pw_set(
username=mqtt_username, password=mqtt_password)
self.client.on_connect = self.on_connect
self.client.subscribe(
"topic")
self.client.connect(broker, mqtt_port)
self.client.loop_start()

将这个类继承给另一个类

class publishdata(Initializer):
def __init__(self):
super().__init__()
self.client.on_message = self.on_message
self.client.on_subscribe = self.on_subscribe
def on_subscribe(self, client, userdata, mid, granted_qos):
print("Subscription started")
def on_message(self, client, userdata, message):
print("message.topic", message.payload)
def begin(self,topic,data):
self.client.publish(
topic, str(data))
publishData = PublishData()
publishData.begin(topic,data)

publish and subscribe工作正常。但是当我调用publishedData .client。连接和客户端。Initializer类中的loop_start也会运行。我不希望每个发布调用都执行这个。有没有更好的方法来做这件事?

Answer 1

如果您不想在每次创建新的PublishData实例时初始化客户端，那么执行此初始化的代码不属于PublishData类。一种可能的解决方案是在PublishData类之外创建客户端并将其传递进去。这被称为依赖注入。它看起来像这样:

def start_client():
client = mqtt.Client(mqtt_server+str(int(time.time()))) 
client.username_pw_set(username=mqtt_username, password=mqtt_password)
client.on_connect = self.on_connect
client.subscribe("topic")
client.connect(broker, mqtt_port)
client.loop_start()
return client

client = start_client()
publish_data = PublishData(client)
publishData.begin(topic,data)