How to use TURN server with PeerJs

In this article we are going to learn how we can use the TURN server with the PeerJS

For this, we are going to create a new PeerJs project

This is going to be a simple webrtc application for learning purposes.

The App is going to connect to another peer using PeerJs and send messages, we are going to use TURN server to bypass the NAT in this example.

For a TURN server we are going to use the Metered TURN servers

Here is what we are going to learn in this article

Getting a TURN server solution (Metered TURN servers)
Setting Up a Simple WebRTC Project Using PeerJS
Integrating Metered TURN servers with PeerJs project
Testing the TURN server and the app

In order to integrate TURN server with PeerJs application, you first need a TURN server.

In order to make things easier, we are going to use the Metered TURN service in this example

Getting a TURN server Solution Metered TURN servers

Step 1: Create a Free account

go to the Metered TURN server website: https://metered.ca/stun-turn

There create a free account. You get unlimited free STUN server usage and 5 gb of free turn server usage when you put in a credit card. That should be enough for our example here

you can also purchase a plan if you like the paid plans are as follows

TURN Growth 150 GB : 99 USD /mo, free 150 GB TURN usage included, 0.40 USD/ GB overage, 99.95% Uptime
TURN Business 500 GB: 199 USD /mo, free 500 GB TURN usage included, 0.20 USD/ GB overage, 99.99% Uptime
TURN Enterprise 2 TB: 499 USD /mo, free 2 TB TURN usage included, 0.10 USD/ GB overage, 99.999% Uptime

Step 2: Creating TURN credentials

When you signup you land up in the dashboard there you can create the TURN credentials

You can manually create credentials and use it in your PeerJS library or
You can use the API to create the credentials as well

While creating the credentials manually is straightforward using the API gives you a lot more features and management control over the TURN server like for example

Add/Remove credentials using the API
Fetch Per-Credential Usage Metrics with API
Enable/Disable teh Credentials with the API
Create auto expiring TURN credentials

You can also select the region, where your TURN server should be located. The recommended is the** Global location**, which automatically routes the traffic to the turn server that is nearest to your users location

apart from this the locations available are

Global
North America Only
E.U Only
Europe Only
Asia Only
Oceana Only
U.S West Only
U.S Central Only
U.S East Only
Canada Central Only
Canada East Only
Europe West Only
Europe Central Only
Asia West Only
Asia East Only
Oceana Only
Canada Only
U.S Only
U.K Only
Seoul Only
Singapore Only
India Only
Australia Only

You can click on the instructions button to know more about the how to use the credential in your app

Setting Up a Simple WebRTC Project Using PeerJS

PeerJS is a wrapper around the web browsers built in webRTC implementation that provides a easy to use peer to peer connection API.

This API is complete, configurable and easy to use API, that handles serialization, peer discovery and connection management

PeerJs is easy to setup for audio/video streaming, file sharing and data channels

Creating a PeerJs Project

In this section we are going to create a new PeerJs project

As stated above, the app is going to be simple webrtc app that is going to connec to another peer and send messages using a TURN server

For a TURN server we are going to use the Metered TURN servers. We have already stated how you can Sign Up for the Metered TURN service above

First, create a nodejs project, create a new directory and name it peerjs then cd into it

step 1: type the npm init command to initialize a new project. This will create a package.json file which will look something like this



{
  "name": "peerjs",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "metered-turn-servers",
  "license": "ISC"
}

Creating the UI of the App. (index.html)

In the root folder create a new file and name it index.html

In the file paste the following code:



<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>PeerJS Example with TURN Server</title>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/peerjs/1.3.2/peerjs.min.js"></script>
    <script src="app.js" defer></script>
</head>
<body>
    <h2>PeerJS WebRTC Communication</h2>
    <div>
        <label for="peerId">Your Peer ID:</label>
        <input type="text" id="peerId" readonly>
    </div>
    <div>
        <label for="otherPeerId">Connect to Peer ID:</label>
        <input type="text" id="otherPeerId">
        <button id="connectButton">Connect</button>
    </div>
    <div>
        <label for="message">Message:</label>
        <input type="text" id="message">
        <button id="sendMessageButton">Send Message</button>
    </div>
    <div id="messages"></div>
</body>
</html>

What are we doing here:

We are importing the peerjs library through CDN. This enables us to use the library
Then we are linking to the external JavaScript File called the app.js, this file contains the logic of the PeerJs app that we are creating
Peer ID Display: In the body section we are creating a label and input that shows the user their own PeerJS ID like so



<div>
    <label for="peerId">Your Peer ID:</label>
    <input type="text" id="peerId" readonly>
</div>

4 Connect to Peer Then in the next section we are allowing the user to connect to another user by putting in the credentials, that is the PeerJs ID of the other user that they want to connect to



<div>
    <label for="otherPeerId">Connect to Peer ID:</label>
    <input type="text" id="otherPeerId">
    <button id="connectButton">Connect</button>
</div>

5 Send Message: Here we have an input field where the user can write a message that they want to send to another user



<div>
    <label for="message">Message:</label>
    <input type="text" id="message">
    <button id="sendMessageButton">Send Message</button>
</div>

6 Message Display: It is a <div> with nothing inside adn an id of messages. In this div we are going to add the messages that are send and received



<div id="messages"></div>

Creating the APP logic (app.js file)

Next create a file in the root directory and name it app.js

Paste the following code in the app.js file



document.addEventListener('DOMContentLoaded', () => {
    const peer = new Peer(undefined, {
        config: {
            iceServers: [
                {
                    urls: "turn:global.relay.metered.ca:80", // Replace with your TURN server URL
                    username: "370e0c14a753092e97cd645f", // Replace with your TURN username
                    credential: "TJ+gyUoqt2xo3oI2", // Replace with your TURN credential
               }
            ]
        }
    });

    const peerIdInput = document.getElementById('peerId');
    const otherPeerIdInput = document.getElementById('otherPeerId');
    const connectButton = document.getElementById('connectButton');
    const messageInput = document.getElementById('message');
    const sendMessageButton = document.getElementById('sendMessageButton');
    const messagesDiv = document.getElementById('messages');

    let dataConnection = null;

    peer.on('open', id => {
        peerIdInput.value = id;
    });

    connectButton.addEventListener('click', () => {
        const otherPeerId = otherPeerIdInput.value;
        if (!otherPeerId) {
            alert('Please enter the other peer ID.');
            return;
        }

        dataConnection = peer.connect(otherPeerId);
        setupDataConnectionEvents();
    });

    sendMessageButton.addEventListener('click', () => {
        const message = messageInput.value;
        if (!message) {
            alert('Please enter a message to send.');
            return;
        }

        if (dataConnection && dataConnection.open) {
            dataConnection.send(message);
            displayMessage(`You: ${message}`);
            messageInput.value = ''; // Clear the input after sending
        } else {
            alert('Data connection is not established. Please connect to a peer first.');
        }
    });

    peer.on('connection', connection => {
        dataConnection = connection;
        setupDataConnectionEvents();
    });

    function setupDataConnectionEvents() {
        dataConnection.on('data', message => {
            displayMessage(`Peer: ${message}`);
        });

        dataConnection.on('open', () => {
            messagesDiv.innerHTML += '<p>Connection established. You can send messages now.</p>';
        });

        dataConnection.on('close', () => {
            alert('Data connection has been closed.');
        });
    }

    function displayMessage(message) {
        messagesDiv.innerHTML += `<p>${message}</p>`;
    }
});

What are we doing here:

(Important) Initializing the code and adding Global variables

let us look at the initializing code and understand what it is doing



document.addEventListener('DOMContentLoaded', () => {
    const peer = new Peer(undefined, {
        config: {
            iceServers: [
                {
                    urls: "turn:global.relay.metered.ca:80", // Use the TURN server URL from Metered
                    username: "370e0c14a753092e97cd645f", // TURN server username Obtained from metered.ca/stun-turn website
                    credential: "TJ+gyUoqt2xo3oI2", // TURN server credentials Obtained from metered.ca/stun-turn
               }
            ]
        }
    });

We wait for the DON to load then we call a function
this function creates a new PeerJs Peer Object. and we pass the undefined as the first argument here
In the config object we add the Metered TURN credentials that we obtained from the metered turn server website: https://metered.ca/stun-turn

UI Elements and Connection Handling



const peerIdInput = document.getElementById('peerId');
const otherPeerIdInput = document.getElementById('otherPeerId');
const connectButton = document.getElementById('connectButton');
const messageInput = document.getElementById('message');
const sendMessageButton = document.getElementById('sendMessageButton');
const messagesDiv = document.getElementById('messages');

let dataConnection = null;

You get the elements from the index.html page like peer ID, input messages etc
dataConnection is initialized with null

Displaying the Peer ID



peer.on('open', id => {
    peerIdInput.value = id;
});

Here the peer js listner waits for the open event. when the peer ID is ready, the id is displayed in the peerIdInput field.

Establishing a Connection



connectButton.addEventListener('click', () => {
    const otherPeerId = otherPeerIdInput.value;
    if (!otherPeerId) {
        alert('Please enter the other peer ID.');
        return;
    }

    dataConnection = peer.connect(otherPeerId);
    setupDataConnectionEvents();
});

When the user clicks on the Connect button, the script to establish a connection to the perr whose ID is entered in the otherPeerInput field runs
It calles the peer.connect and passes the other peer's ID and assigns the returned data connection object to dataConnection setupDataConnectionEvents is called to initiaze event listners for the new connection

Sending Messages



sendMessageButton.addEventListener('click', () => {
    const message = messageInput.value;
    if (!message) {
        alert('Please enter a message to send.');
        return;
    }

    if (dataConnection && dataConnection.open) {
        dataConnection.send(message);
        displayMessage(`You: ${message}`);
        messageInput.value = '';
    } else {
        alert('Data connection is not established. Please connect to a peer first.');
    }
});

Here we are listning on the Send message button. If something is typed in the input field and the connection is established we send the message
The sent messages are also displayed on the messagesDiv after the You: text and the input is cleared

Receiving Connections and Messages



peer.on('connection', connection => {
    dataConnection = connection;
    setupDataConnectionEvents();
});

Nest we are listning for the connections when another peer connects to this peer then we save the connection object in the dataConnection variable and similar to outgoing connections the event listners are setup by the library

Handling connection events



function setupDataConnectionEvents() {
    dataConnection.on('data', message => {
        displayMessage(`Peer: ${message}`);
    });

    dataConnection.on('open', () => {
        messagesDiv.innerHTML += '<p>Connection established. You can send messages now.</p>';
    });

    dataConnection.on('close', () => {
        alert('Data connection has been closed.');
    });
}

Here there are a few things that are hapening

setupDataConnectionEvents function adds listners for the data, open and close events to the current data connection
data event listener displays incoming messages
open event adds a message to the messageDiv, telling us that a connection has been established close event alerts the user that the connection has been closed

Displaying Messages



function displayMessage(message) {
    messagesDiv.innerHTML += `<p>${message}</p>`;
}

this function adds messages to the messagesDiv thus showing messages on the screen

Metered TURN servers

API: TURN server management with powerful API. You can do things like Add/ Remove credentials via the API, Retrieve Per User / Credentials and User metrics via the API, Enable/ Disable credentials via the API, Retrive Usage data by date via the API.
Global Geo-Location targeting: Automatically directs traffic to the nearest servers, for lowest possible latency and highest quality performance. less than 50 ms latency anywhere around the world
Servers in 12 Regions of the world: Toronto, Miami, San Francisco, Amsterdam, London, Frankfurt, Bangalore, Singapore,Sydney, Seoul
Low Latency: less than 50 ms latency, anywhere across the world.
Cost-Effective: pay-as-you-go pricing with bandwidth and volume discounts available.
Easy Administration: Get usage logs, emails when accounts reach threshold limits, billing records and email and phone support.
Standards Compliant: Conforms to RFCs 5389, 5769, 5780, 5766, 6062, 6156, 5245, 5768, 6336, 6544, 5928 over UDP, TCP, TLS, and DTLS.
Multi‑Tenancy: Create multiple credentials and separate the usage by customer, or different apps. Get Usage logs, billing records and threshold alerts.
Enterprise Reliability: 99.999% Uptime with SLA.
Enterprise Scale: With no limit on concurrent traffic or total traffic. Metered TURN Servers provide Enterprise Scalability
5 GB/mo Free: Get 5 GB every month free TURN server usage with the Free Plan
Runs on port 80 and 443
Support TURNS + SSL to allow connections through deep packet inspection firewalls.
Support STUN
Supports both TCP and UDP

Conclusion

Thus in this article we have learned how we can add a turn server to a peer js project.

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