OCPP server

//! README

// set charging limit
// curl 'http://HOST:3030/limit?amps=10.4&numberPhases=3'

// stop charging
// curl 'http://HOST:3030/stop'

// start charging
// curl 'http://HOST:3030/start?amps=10&numberPhases=3'


const express = require('express');
const WebSocket = require('ws');
const http = require('http');

const app = express();
const server = http.createServer(app);

const wss = new WebSocket.Server({ server });

const clients = [];

wss.on('connection', (ws) => {
    console.log('Client connected via WebSocket');
    clients.push(ws);
    ws.on('close', (code, reason) => {
        console.log(`Connection closed. Code: ${code}, Reason: ${reason}`);
        const i = clients.indexOf(ws);
        if (i !== -1) {
            clients.splice(i, 1);
        }
    });


    ws.on('message', (message) => {
        console.log('>> Got:', JSON.stringify(JSON.parse(message.toString()), null));
        handleMessage(ws, message);
    });
});

function handleMessage(ws, message) {
    let parsedMessage;

    try {
        parsedMessage = JSON.parse(message);
    } catch (error) {
        console.error('Error parsing message', message);
        return;
    }

    const response = replyMessage(parsedMessage);
    if (response) {
        console.log('<< Reply:', JSON.stringify(response, null));
        ws.send(JSON.stringify(response));
    }
    console.log('-----------------------')
}

function replyMessage(message){
    const [messageTypeId, uniqueId, action, payload] = message;
    var replyCounter = 0;
    //initiated by Charging Station
    if (uniqueId.startsWith("xxx")) {
        // got reply not request
        return;
    }else if (action === "BootNotification") {
        return [3, uniqueId, { "status": "Accepted", "currentTime": new Date().toISOString(), "interval": 10 }]; //fixed Heartbeat Interval

    }else if (action === "StartTransaction") {
        return [3, uniqueId, {
            "transactionId": 123,
            "idTagInfo": {
                "status": "Accepted",
            },
        }];

    }else if (action === "StopTransaction") {
        return [3, uniqueId, {
            "idTagInfo": {
                "status": "Accepted",
            },
        }];

    }else if(action === "Heartbeat") {
        return [3, uniqueId, { "currentTime": new Date().toISOString() }];

    }else if(action === "StatusNotification"){
        return [3, uniqueId, {}];

    }else if(action === "MeterValues"){
        return [3, uniqueId, {}];

    }else if(action === "Authorize"){
        // Check if ID in Backend in the future, or similar
        return [3, uniqueId, { idTagInfo: { "status": "Accepted" } }];

    // Initiated by FrontEnd
    // -- Reset
    }else if(action === "Reset"){
        // Check if ID in Backend in the future, or similar
        replyCounter = replyCounter+1;
        return [2, replyCounter.toString(), "Reset", { type: "Hard" }];

    // -- Remote Start Transaction
    // }else if(action === "RemoteStartTransactionRequest"){
    //  // Check if ID in Backend in the future, or similar
    //  replyCounter = replyCounter+1;
    //  return [2, replyCounter.toString(), "RemoteStartTransactionRequest",{"idTag":"6ac32b40","connectorId":1}];
    // // -- Remote Stop Transaction
    // }else if(action === "RemoteStopTransactionRequest"){
    //  // Check if ID in Backend in the future, or similar
    //  replyCounter = replyCounter+1;
    //  return [2, replyCounter.toString(), "RemoteStopTransactionRequest", { "transactionId": 1}];

    }else{
        console.log("Unknown MEssage!!!!");
        console.log("*****");
        console.log(message);
        console.log("*****");
    };
}


app.get('/', (req, res) => {
    res.send('Hello from Express and WebSocket OCPP Server');
});
app.get('/limit', (req, res) => {
    const currentLimit = +req.query.amps;
    const numberPhases = +(req.query.numberPhases || 3);
    if (clients.length) {
        const message = [2, `xxx${Date.now()}`, "SetChargingProfile", {
            "connectorId": 1,
            "csChargingProfiles": {
                "chargingProfileId": 1,
                "transactionId": 123,
                "stackLevel": 0,
                "chargingProfilePurpose": "ChargePointMaxProfile",
                "chargingProfileKind": "Absolute",
                "chargingSchedule": {
                    "chargingRateUnit": "A",
                    "chargingSchedulePeriod": [
                        {
                            "startPeriod": 0,
                            "limit": currentLimit,
                            "numberPhases": numberPhases,
                        }
                    ]
                }
            }
        }];
        for (const ws of clients) {
            ws.send(JSON.stringify(message));
        }
        console.log('<< Send:', JSON.stringify(message, null));
        res.send(`Message sent\n${JSON.stringify(message, null, 2)}`);
    }else {
        res.status(400).send('No connected client');
    }
});
app.get('/stop', (req, res) => {
    if (clients.length) {
        const message = [2, `xxx${Date.now()}`, "RemoteStopTransaction", {
            "transactionId": 123,
        }];
        for (const ws of clients) {
            ws.send(JSON.stringify(message));
        }
        console.log('<< Send:', JSON.stringify(message, null));
        res.send(`Message sent\n${JSON.stringify(message, null, 2)}`);
    }else {
        res.status(400).send('No connected client');
    }
});
app.get('/start', (req, res) => {
    const currentLimit = +(req.query.amps || 10);
    const numberPhases = +(req.query.numberPhases || 3);
    if (clients.length) {
        const message = [2, `xxx${Date.now()}`, "RemoteStartTransaction", {
            "connectorId": 1,
            "idTag": "SomeIdTaggggg",
            "chargingProfile": {
                "chargingProfileId": 1,
                "transactionId": 123,
                "stackLevel": 0,
                "chargingProfilePurpose": "ChargePointMaxProfile",
                "chargingProfileKind": "Absolute",
                "chargingSchedule": {
                    "chargingRateUnit": "A",
                    "chargingSchedulePeriod": [
                        {
                            "startPeriod": 0,
                            "limit": currentLimit,
                            "numberPhases": numberPhases,
                        }
                    ]
                }
            },
        }];
        for (const ws of clients) {
            ws.send(JSON.stringify(message));
        }
        console.log('<< Send:', JSON.stringify(message, null));
        res.send(`Message sent\n${JSON.stringify(message, null, 2)}`);
    }else {
        res.status(400).send('No connected client');
    }
});

server.listen(3030, () => {
    console.log('HTTP and WebSocket server is running on http://localhost:3030');
});