server.js

const express = require('express');
const app = express();
const path = require('path');

const isLocal = process.env.NODE_ENV !== 'production';
const PORT = process.env.PORT || 8080;
const HOST = isLocal ? '192.168.0.21' : undefined;

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
    next();
});

app.use(express.json());

let latestPM = {
    cf_pm1_0: 0,
    cf_pm2_5: 0,
    cf_pm10: 0,
    atm_pm1_0: 0,
    atm_pm2_5: 0,
    atm_pm10: 0,
    particles_1_0: 0,
    particles_2_5: 0,
    particles_10: 0
};

app.post('/pm', (req, res) => {
    latestPM = req.body;
    if (latestPM && Object.keys(latestPM).length > 0) {
        res.status(200).send({ message: 'Data receive success' });
    } else {
        res.status(400).send({ message: 'Error data format' });
    }
});

app.get('/latest-pm', (req, res) => {
    res.json(latestPM);
});

app.use(express.static(path.join(__dirname, 'frontend/dist')));

app.get('*', (req, res) => {
    res.sendFile(path.join(__dirname, 'frontend/dist/index.html'));
});

if (isLocal) {
    app.listen(PORT, HOST, () => {
        console.log(`Local Server running at http://${HOST}:${PORT}`);
    });
} else {
    app.listen(PORT, () => {
        console.log(`GCP Server running at PORT ${PORT}`);
    });
}