node-opcua-client-proxy

import { OPCUAClient, MessageSecurityMode, SecurityPolicy, ClientSession, TimestampsToReturn, AttributeIds } from 'node-opcua'; import { ClientProxy } from 'node-opcua-client-proxy'; const endpointUrl = process.env.OPCUA_ENDPOINT_URL ?? 'opc.tcp://localhost:4840'; const userIdentity = { userName: process.env.OPCUA_USERNAME ?? 'user', password: process.env.OPCUA_PASSWORD ?? 'password' }; async function connectAndRead() { const client = OPCUAClient.create({ endpointUrl: endpointUrl, securityMode: MessageSecurityMode.None, // For demo purposes, consider stronger security in production securityPolicy: SecurityPolicy.None, // clientCertificateManager: provide a proper cert manager in production connectionStrategy: { maxRetry: 5, initialDelay: 500, maxDelay: 3000 } }); client.on('backoff', (retry, delay) => { console.log(`Connection attempt failed. Retrying in ${delay / 1000}s (attempt ${retry})`); }); let session: ClientSession | null = null; try { console.log(`Connecting to ${endpointUrl}...`); await client.connect(endpointUrl); console.log('Connected to OPC UA server.'); session = await client.createSession(userIdentity); console.log(`Session created with id: ${session.sessionId.toString()}`); // Instantiate the ClientProxy with the established session const proxy = new ClientProxy(session); // Example: Reading a specific node's value via the proxy (assuming proxy has a 'read' method) const nodeIdToRead = 'ns=2;s=MyDevice/Temperature'; // Replace with a valid NodeId from your server console.log(`Attempting to read NodeId: ${nodeIdToRead}`); // Using session.read directly for now as proxy API is inferred const dataValue = await session.read({ nodeId: nodeIdToRead, attributeId: AttributeIds.Value, timestampsToReturn: TimestampsToReturn.Both }); if (dataValue.statusCode.isGood()) { console.log(`Value of ${nodeIdToRead}: ${dataValue.value?.value} (Source Timestamp: ${dataValue.sourceTimestamp?.toISOString()})`); } else { console.error(`Failed to read ${nodeIdToRead}: ${dataValue.statusCode.toString()}`); } } catch (err) { console.error('An error occurred during OPC UA communication:', err); } finally { if (session) { await session.close(); console.log('Session closed.'); } if (client) { await client.disconnect(); console.log('Disconnected from OPC UA server.'); } } } connectAndRead();