Develop an IoT asset tracking app using Block chain. Use an IoT asset tracking device to improve a supply chain by using Block chain, IoT devices, and Node-RED.
- app.js → Express server + simulated blockchain ledger
- iotContract.js → ledger logic
- iot-ledger.json → initial empty ledger
- index.html → web frontend with form and fetch POST to /track
iotContract.js
// iotContract.js
import fs from "fs";
const LEDGER_FILE = "./iot-ledger.json";
export class IoTAssetContract {
constructor() {
if (!fs.existsSync(LEDGER_FILE)) {
fs.writeFileSync(LEDGER_FILE, JSON.stringify([]));
}
}
async addAsset(assetId, location, temperature) {
const ledger = JSON.parse(fs.readFileSync(LEDGER_FILE));
const entry = {
assetId,
location,
temperature,
timestamp: new Date().toISOString()
};
ledger.push(entry);
fs.writeFileSync(LEDGER_FILE, JSON.stringify(ledger, null, 2));
return entry;
}
async getAllAssets() {
return JSON.parse(fs.readFileSync(LEDGER_FILE));
}
}
iot-ledger.json
[]
app.js
// app.js
import express from "express";
import bodyParser from "body-parser";
import path from "path";
import { fileURLToPath } from "url";
import { IoTAssetContract } from "./iotContract.js";
// Setup __dirname for ES Modules
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const app = express();
app.use(bodyParser.json());
// Serve static files from /public
app.use(express.static(path.join(__dirname, "public")));
const contract = new IoTAssetContract();
// Root route
app.get("/", (req, res) => {
res.sendFile(path.join(__dirname, "public", "index.html"));
});
// POST /track — add IoT asset
app.post("/track", async (req, res) => {
try {
if (!req.body || Object.keys(req.body).length === 0) {
return res.status(400).json({ error: "Empty or invalid JSON body" });
}
const { assetId, location, temperature } = req.body;
if (!assetId || !location || temperature === undefined) {
return res.status(400).json({ error: "Missing required fields" });
}
const result = await contract.addAsset(assetId, location, temperature);
res.json(result);
} catch (err) {
res.status(500).json({ error: err.toString() });
}
});
// GET /assets — view all assets
app.get("/assets", async (req, res) => {
try {
const result = await contract.getAllAssets();
res.json(result);
} catch (err) {
res.status(500).json({ error: err.toString() });
}
});
// Start server
const PORT = 3000;
app.listen(PORT, () => {
console.log(`IoT Asset Tracking app running on port ${PORT}`);
});
public/index.html
IoT Asset Tracking
IoT Asset Tracking Simulation
Tracked Assets
Loading...
if error,
Rename app.js to app.cjs
and use "node app.cjs" to run