Python 基于OPC UA的对象的Push与pull 事件驱动实现机制

版权声明：本文为博主原创文章，请转载时注明出处，欢迎浏览！ https://blog.csdn.net/leemboy/article/details/81107378

OPCUA Server侧Push代码如下：

--------------------------------------------

import logging
import pickle
import random

from opcua import ua, Server

class data_struct:
    def _init_(self,para1,para2,para3):
        self.para1=para1
        self.para2=para2
        self.para3=para3
        ###..................................

if __name__ == "__main__":
#the following is only for debuging
    logging.basicConfig(level=logging.WARN)
    logger = logging.getLogger("opcua.server.internal_subscription")
    logger.setLevel(logging.DEBUG)#logging level of this logger: 10

    server = Server()
    server.set_endpoint("opc.tcp://127.0.0.1:4840/freeopcua/server/")

    # setup  namespace
    uri = "http://examples.io"# this can be any
    idx = server.register_namespace(uri) #register the uri name space in the server
    print("idx is :",idx)
    objs = server.get_objects_node()
    print("obj is: ", objs)
    myobj = objs.add_object(idx, "OT_Object")    # populating our address space
    print("myobj is: ",myobj)
    data = data_struct()
    custom_etype = server.nodes.base_event_type.add_object_type(1, 'TSS_EVENT_MSG')

    print("custom_etype is: ",custom_etype)
    server.start()

    try:
        import time
        count=0
        while True:
            time.sleep(3)
	#we only use random value as a demo
            data.para1 = 12345+random.randint(10,90)
            data.para2 = "para2"+str(random.randint(10,90))
            data.para3 = "para3"+str(random.randint(10,90))
            data_byte = pickle.dumps(data)  #Serilization 
	#Here 'MyObjProperty' is a object property name which can be indexed and accessed in client side.
            custom_etype.add_property(0, 'MyObjProperty', ua.Variant(data_byte, ua.VariantType.ByteString))
            event_obj = server.get_event_generator(custom_etype, myobj)
            event_obj.event.Security =count
	#Trigger the messager push with the message name "YOUR_EVENT_MSG_NAME”
            event_obj.trigger(message="YOUR_EVENT_MSG_NAME %d" % count)
            count += 1
            #embed()
    finally:
        server.stop()

-----------------------------------------------------------------

OPCUA Client 侧基于事件驱动的对象Pull代码

import pickle
from IPython import embed
from opcua import Client
class data_struct:
    def _init_(self,para1,para2,para3):
        self.para1=para1
        self.para2=para2
        self.para3=para3
        #.................................
class SubHandler(object):
#this is event notification , you can get object and deseriliazation it
    def event_notification(self, event):
        data_st=data_struct()
        data_st=pickle.loads(event.MyObjProperty)
        print("************************************")
        print("Data para1: ",data_st.para1)
        print("Data para2: ",data_st.para2)
        print("Data para3: ",data_st.para3)
if __name__ == "__main__":
    server_url="opc.tcp://127.0.0.1:4840/freeopcua/server/"
    client = Client(server_url)
    try:
        client.connect()
        root = client.get_root_node()
        print("root is :",root)
        obj = root.get_child(["0:Objects", "2:OT_Object"])
        print("obj is: ",obj)
        myevent_tss = root.get_child(["0:Types", "0:EventTypes","0:BaseEventType",  "1:YOUR_EVENT_MSG_NAME"])
        print("event is: ",myevent_tss)
        msclt_tss = SubHandler()
        sub_tss = client.create_subscription(100, msclt_tss)
        handle_tss = sub_tss.subscribe_events(obj, myevent_tss)
        embed()
        sub_tss.unsubscribe(handle_tss)
        sub_tss.delete()
    finally:
        client.disconnect()