Unlocking Real-Time Communication in React Native with WebRTC

Introduction to WebRTC

WebRTC (Web Real-Time Communication) is a powerful technology that enables web applications to capture and stream audio and video streams. With its availability on all modern browsers and major native platforms, it has become the de facto way to build video conferencing applications.

Building the Demo Application

Our demo application is a simple video call app that allows users to initiate or join a call. We’ll use Firebase Firestore as our signaling server to facilitate communication between peers.

Installation

1. Create a blank React Native project:

   npx react-native init myproject

2. Install the react-native-webrtc plugin:

   npm install react-native-webrtc

3. Update the Info.plist file for iOS and the AndroidManifest.xml file for Android to request the necessary permissions.

Creating the Real-Time Chat App

To create our real-time chat app, we need to create an instance of RTCPeerConnection, which will manage the connection between the local computer and a remote peer. We’ll also need to capture the local stream from the user’s camera and add it to the RTCPeerConnection.

import { RTCPeerConnection } from 'react-native-webrtc';

const pc = new RTCPeerConnection();

Signaling Server

For our signaling server, we’ll use Firebase Firestore to facilitate communication between peers. We’ll create a document in Firestore to store the communication channels and use the createOffer() method to initiate a call.

import { db } from './firebase';

const channelRef = db.collection('channels').doc('channel-id');

pc.createOffer().then((offer) => {
  channelRef.set({ offer });
});

Initiating a Call

To initiate a call, we’ll create an offer and write it to the channel’s document in Firestore. We’ll then listen for updates to the channel document and add any new candidates to the RTCPeerConnection.

channelRef.onSnapshot((snapshot) => {
  const offer = snapshot.data().offer;
  pc.addIceCandidate(new RTCIceCandidate(offer));
});

Answering a Call

To answer a call, we’ll create an answer offer and update the channel document in Firestore. We’ll also listen for any changes to the offer candidates sub-collection.

pc.createAnswer().then((answer) => {
  channelRef.update({ answer });
});

channelRef.collection('candidates').onSnapshot((snapshot) => {
  snapshot.forEach((candidate) => {
    pc.addIceCandidate(new RTCIceCandidate(candidate.data()));
  });
});

Putting it all Together

Finally, we’ll call the functions to start or join a call when the user initiates or answers a call.