app-web-3d-hmi-demo.js

var nodes7 = require('nodes7');
var config = require('./config');

var s7conn = new nodes7;

const express = require('express');
const app = express();
app.use(express.json());

////////////////////////////////////////////////////////////////////////
// S7 handling

var globalValues;

var variables = config.plc.vars;
s7conn.initiateConnection({port: 102, host: config.plc.host, rack: config.plc.rack, slot: config.plc.slot}, connected);

function cyclicReadFromPlc()
{
    s7conn.readAllItems(valuesReady);
}

function connected(err) {
	if (typeof(err) !== "undefined") {
		console.log("ERROR: CANNOT CONNECT TO S7 PLC");
		console.log(err);
	}
	s7conn.setTranslationCB(function(tag) {return variables[tag];});
    s7conn.addItems(Object.keys(variables));
	s7conn.readAllItems(valuesReady);
    setInterval(cyclicReadFromPlc, config.plc.pollinterval);
}

function valuesReady(err, values) {
	if (err) { console.log("ERROR: READING VALUES FROM S7 PLC FAILED!"); }
    globalValues = values;
}

function valuesWritten(err) {
    if (err) { console.log("ERROR: WRITING VALUES TO S7 PLC FAILED!"); }
}

////////////////////////////////////////////////////////////////////////
// HTTP Server handling
app.use(express.static('public'));

app.listen(config.webserver.port, function(){
	console.log("Webserver is listening on port", config.webserver.port);
});

app.get('/getvalues', function(req, res) {
    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify(globalValues));
});

app.post('/setvalues', function(req, res) {
    res.setHeader('Content-Type', 'application/json');
    data = req.body;
    for (let [k, v] of Object.entries(data)) {
        s7conn.writeItems(k,v, valuesWritten);
    }
    res.end(JSON.stringify(globalValues));
});

// Subcription
// Parameter: accessname : address
app.post('/subscribe', function(req, res) {
    res.setHeader('Content-Type', 'application/json');
    data = req.body;
    console.log(data);
    for (let [name, address] of Object.entries(data)) {
        variables[name] = address;
        s7conn.addItems(name);
    }
    res.end(JSON.stringify(variables));
});

// Unsubscribe
// Parameter: accessname
app.post('/unsubscribe', function(req, res) {
    res.setHeader('Content-Type', 'application/json');
    data = req.body;
    console.log(data);
    var name = data[0];
    delete variables[name];
    s7conn.removeItems(name);
    res.end(JSON.stringify(variables));
});