Set Up a Connection Over WebSocket: Video Call with WebRTC Step 2

Photo by Cytonn Photography on Unsplash

We want to create a video chat using the WebRTC protocol. We saw in the previous article how to access the webcam and microphone streams from the browser. We now want to establish a P2P connection between two users.

The WebRTC connection between your local browser and a remote user (peers) will be represented by the JavaScript interface RTCPeerConnection. But you have to coordinate this connection first, exchanging messages between peers to find each other, control the communication and then terminate it. This is the signaling process. The signaling process is not part of the WebRTC specifications, you are free to use whatever messaging protocol you want to establish and control the connection. You could technically deliver those messages per post, but a common solution is to use the WebSocket protocol.

In this article, we are going to allow two users to communicate over WebSocket. We are going to build an example with a Node server, in which peers can create a connection, say hello to each other, and close the connection.

WebSocket

WebSocket is a communication protocol, kind of a concurrent to HTTP. Like HTTP, WebSocket enables the communication between a client (a browser) and a server.

When communicating over HTTP, the server can only react to the client’s requests. It doesn’t remember anything about previous requests, HTTP is stateless. WebSocket, on the other hand, lets you open a channel between the client and the server. Once this channel is open and until it gets closed, the communication can happen both ways: the server can send data when it likes, and so can the client.

WebSocket is actually designed to work over HTTP, so we can use a normal web server to build it on. We are going to implement a WebSocket communication between our client and a Node server.

Set up the Node project

We are going to use a Node server for this with a library implementing WebSocket: WebSocket-Node.

If you don’t already have it on your machine, you should install Node.js. Create the folder in which you want to have your WebSocket project (I named mine web-socket). Then into that folder initialize your…