node.js - 爬取地址空间中的所有对象

Question

我正在尝试抓取地址空间中的对象。目的是存储它，然后创建一个包含对象的 XML 文件。有谁知道该怎么做？

Answer 1

这是 TypeScript 中的一个示例，使用按原样提供的 node-opcua 可能是一个很好的起点：

import { OPCUAClient, ClientSession, NodeCrawler, CacheNode, UserData, BrowseDirection, NodeClass, CacheNodeVariable, DataType } from "node-opcua";
const endpointUrl = "opc.tcp://opcuademo.sterfive.com:26543";
const js2xml = require("js2xmlparser");

const nodeId = "ns=1;i=1000"; // MyDevices
(async () => {
    try {
        function onBrowse(crawler: NodeCrawler, cacheNode: CacheNode, userData: UserData) {
            if (cacheNode.nodeClass === NodeClass.ReferenceType) {
                return;
            }
            const node: any = { "@": {} };
            node["@"].nodeClass = NodeClass[cacheNode.nodeClass];
            if (cacheNode.nodeClass === NodeClass.Variable) {
                const cacheNodeVariable = (cacheNode as CacheNodeVariable);
                node["@"].dataType = DataType[cacheNodeVariable.dataValue.value.dataType];
                if (typeof cacheNodeVariable.dataValue.value.value !== "object") {
                    node["#"] = cacheNodeVariable.dataValue.value.value;
                } else {
                    node.value = cacheNodeVariable.dataValue.value.value;
                }
            }
            const myUserData = {
                onBrowse,
                root: node,
            };
            (userData as any).root[cacheNode.browseName.name.toString()] = node;
            if (cacheNode.nodeClass === NodeClass.Variable) {
                return;
            }
            NodeCrawler.follow(crawler, cacheNode, myUserData, "Organizes", BrowseDirection.Forward);
            NodeCrawler.follow(crawler, cacheNode, myUserData, "HasComponent", BrowseDirection.Forward);
            NodeCrawler.follow(crawler, cacheNode, myUserData, "HasProperty", BrowseDirection.Forward);
        }
        const client = OPCUAClient.create({ endpoint_must_exist: false });
        client.on("backoff", () => { console.log("keep trying to connect"); });
        const pojo = await client.withSessionAsync(endpointUrl, async (session: ClientSession) => {
            const crawler = new NodeCrawler(session);
            const userData = { onBrowse, root: {} };
            await crawler.crawl(nodeId, userData);
            return userData.root;
        });
        console.log(js2xml.parse("data", pojo));
    } catch (err) {
        console.log(err);
        process.exit(1);
    }
})();

这个例子将产生这样的输出

<?xml version='1.0'?>
<data>
    <MyDevices nodeClass='Object'>
        <FanSpeed nodeClass='Variable' dataType='Double'>1009.7567008059738</FanSpeed>
        <PumpSpeed nodeClass='Variable' dataType='Double'>288.4219646868176</PumpSpeed>
        <SomeDate nodeClass='Variable' dataType='DateTime'>
            <value>Thu Oct 13 2016 10:40:00 GMT+0200 (GMT+02:00)</value>
        </SomeDate>
        <Pressure nodeClass='Variable' dataType='Double'>0.3612702142780426</Pressure>
        <Temperature nodeClass='Variable' dataType='Double'>28.789330946565517</Temperature>
        <TemperatureAnalogItem nodeClass='Variable' dataType='Double'>19.418976965847598</TemperatureAnalogItem>
    </MyDevices>
</data>