Real-Time Location Tracking with Node.js and Pulsetracker's Redis Pub/Sub

Introduction

Real-time location tracking is at the heart of many modern applications, from delivery services to personal tracking tools. Pulsetracker simplifies this process by offering a dedicated Redis Pub/Sub server that allows developers to subscribe to real-time location updates on the backend. In this guide, we'll demonstrate how to build a Node.js application that listens to these updates and processes location data in real time.

---

Why Pulsetracker?

Pulsetracker eliminates the complexity of building a backend for real-time location tracking. It provides a scalable infrastructure with privacy-focused options and features like WebSocket dispatching, Redis Pub/Sub integration, and configurable privacy settings.

---

Why Node.js?

Node.js is a perfect choice for real-time applications due to its non-blocking, event-driven architecture. Using Redis Pub/Sub in Node.js enables you to handle real-time data streams efficiently.

---

Setting Up the Node.js Environment

Prerequisites:

• Node.js installed
• Redis client library (ioredis) installed
• Pulsetracker account and API credentials

Step 1: Install Dependencies

Run the following command to install the necessary Redis library:

npm install ioredis

---

Step 2: Configure Your Application

Create a .env file and add your Pulsetracker Redis configuration:
(Get your APP_KEY and TOKEN from pulsestracker dashboard)

PULSETRACKER_REDIS_URL=redis://redis-sub.pulsestracker.com:6378
APP_KEY=YOUR_APP_KEY
TOKEN=YOUR_TOKEN

---

Step 3: Write the Node.js Subscriber

Here’s an example Node.js script to listen for location updates:

const Redis = require("ioredis");
require("dotenv").config();

// Configuration
const redisUrl = process.env.PULSETRACKER_REDIS_URL;
const appKey = process.env.APP_KEY;
const token = process.env.TOKEN;

// Generate the signature
function generateSignature(appKey, token) {
  const crypto = require("crypto");
  const [prefix, secret] = token.split("|");
  if (!secret) throw new Error("Invalid token format");

  const innerHash = crypto.createHash("sha256").update(secret).digest("hex");
  return crypto.createHmac("sha256", innerHash).update(appKey).digest("hex");
}

const signature = generateSignature(appKey, token);
const channel = `app:${appKey}.${signature}`;

// Connect to Redis
const redis = new Redis(redisUrl);

console.log(`Subscribing to channel: ${channel}`);
redis.subscribe(channel, (err, count) => {
  if (err) {
    console.error("Failed to subscribe:", err);
    process.exit(1);
  }
  console.log(`Successfully subscribed. Waiting for messages...`);
});

// Listen for messages
redis.on("message", (channel, message) => {
  console.log(`Received message ${message}`);
});

---

How It Works

1. Environment Configuration: Redis connection URL and credentials are stored securely in the .env file.
2. Signature Generation: The app generates a secure channel signature using HMAC to subscribe to the correct channel.
3. Redis Subscription: The application listens for real-time location updates published to the Redis channel.

---

Running the Application

1. Save the script as subscriber.js.
2. Run the script using:

node subscriber.js

1. Your application will log real-time location updates received from Pulsetracker.

Example LOG :

{"point":{"type":"Point","coordinates":[-0.070906,51.509816]},"appId":"a9b8dffd-e68c-4bff-95cd-21fbcb86fcfb","clientId":"3faffcfa-d486-4e38-9598-e27ff129b6e9","extraData":{"speed":100}}

---

Conclusion

Pulsetracker's Redis Pub/Sub integration makes it simple to build robust real-time location tracking applications. With Node.js, you can process these updates in real-time, enabling seamless backend operations for your apps.

Explore Pulsetracker's documentation to learn more about its features and start building scalable tracking solutions today!