api.js

require('dotenv').config();
const port = process.env.SYSINFOAPI_PORT || 1337;
const express = require('express');
const https = require('https');
const fs = require('fs');
const PC = require("./classes/PC");

const app = express();
const currentPC = new PC();

const cachingPeriod = 4500; // Time in MS to return a previous version of pcStats if time hasn't passed.
let lastCpuUpdate = 0;
let lastMemUpdate = 0;
let lastHddUpdate = 0;
let lastAllUpdate = 0;

app.get('/', (req, res) => {
    res.setHeader('Content-Type', 'text/html');
    res.header('Access-Control-Allow-Origin', '*');
    res.send("<a href=/cpu>CPU</a><br/><a href=/memory>Memory</a><br/><a href=/hdd>HDDs</a><br/><a href=/all>All</a>");
});
app.get('/cpu', async (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.header('Access-Control-Allow-Origin', '*');

    if ((Date.now() - lastCpuUpdate) > cachingPeriod) {
        res.send(JSON.stringify(await currentPC.getCPU(), null, 2));
        lastCpuUpdate = Date.now();
    } else {
        res.send(JSON.stringify(currentPC.CPU, null, 2));
    }
});
app.get('/memory', (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.header('Access-Control-Allow-Origin', '*');
    if ((Date.now() - lastMemUpdate) > cachingPeriod) {
        res.send(JSON.stringify(currentPC.getMemory(), null, 2));
        lastMemUpdate = Date.now();
    } else {
        res.send(JSON.stringify(currentPC.Memory, null, 2));
    }
});
app.get('/hdd', async (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.header('Access-Control-Allow-Origin', '*');

    if ((Date.now() - lastHddUpdate) > cachingPeriod) {
        res.send(JSON.stringify(await currentPC.getHDDs(), null, 2));
        lastHddUpdate = Date.now();
    } else {
        res.send(JSON.stringify(currentPC.HDDs, null, 2));
    }
    
});
app.get('/all', async (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.header('Access-Control-Allow-Origin', '*');

    if ((Date.now() - lastAllUpdate) > cachingPeriod) {
        res.send(JSON.stringify(await currentPC.getAll(), null, 2));
        lastAllUpdate = Date.now();
    } else {
        res.send(JSON.stringify(currentPC, null, 2));
    }
    
});
app.get('/current', async (req, res) => {
    res.setHeader('Content-Type', 'application/json');
    res.header('Access-Control-Allow-Origin', '*');

    res.send(JSON.stringify(currentPC, null, 2));
});

const options = {
  key: fs.readFileSync('api_cert.key'),
  cert: fs.readFileSync('api_cert.cert'),
};

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.status(404).send("Not found.");
  });

const server = https.createServer(options, app);

server.listen(port, () => {
  console.log(`Server is running on https://localhost:${port}`);
});