How to set value of a NODE inside the datachange_notification ?

[dibyendumca]

**Hello,
I have a requirement as follows.

I want to update the value of a NODE as soon as I get the datachange_notification of another specific NODE.
I have the client code as follows...**

import asyncio
from asyncua import ua, Client, Node
from asyncua.client.ua_client import UaClient

class SubHandler(object):
    def __init__(self, clientId):
        self.clientId = clientId

    def datachange_notification(self, node, value, Data):
    if str(node) == "ns=2;i=19":
          curStat = self.clientId.get_node("ns=2;i=6")
          await curStat.set_value(value)

But I could not call this " await curStat.set_value(value) " inside a non async function.
I get the following ERROR...

await curStat.set_value(value)
^
SyntaxError: 'await' outside async function

[schroeder-]

You can use a async function aswell:

class SubHandler(object):
    def __init__(self, clientId):
        self.clientId = clientId

    async def datachange_notification(self, node, value, Data):
    if str(node) == "ns=2;i=19":
          curStat = self.clientId.get_node("ns=2;i=6")
          await curStat.set_value(value)

[dibyendumca]

Hello @schroeder-

Thanks very much, it worked.

[dibyendumca]

Hello @schroeder-

How can I get the value of a node within my Server component?
I mean to say, is it possible to write the following code in my Server component?

         n = server.get_node("ns=2;i=20")
         val = n.get_value()

[schroeder-]

the server has the same interface for interacting with the addres space (variables, objects...) as the client.
But I think you you miss the await:

n = server.get_node("ns=2;i=20")
val = await n.get_value()

[dibyendumca]

Hello @schroeder- ,

I have added the following code in my Server Component
server.get_objects_node().add_variable(ua.NodeId.from_string((ua.NodeId.from_string("ns=2;s=SIMULATION"), "2:SIMULATION", 0)

I have coded in my Client Component as follows?

cNode = client.get_node("ns=2;s=SIMULATION")
handleData = await sub.subscribe_data_change(cNode)

But I do not get the datachange_notification for this particular NODE.
Can you please suggest some knowhow?