The Node.js-based WebSocket server provides the communication between the Red5 Pro Mixer testbeds, used to create compositions, and the HTML5 sample pages used for defining the layout of the composite streams when loaded into Red5 Pro Mixer nodes. This allows for creating dynamic compositions or video conferences where a Manager or Host can add or remove live streams in real-time. In addition, the Node.js server can act as the endpoint for round-trip authentication, if used.

NOTE: The mixer back end referenced in this document is intended as a mock/placeholder and must be replaced by your own back-end WebSocket server.

Deploying The Node.js Backend Server

The Node.js Backend For Mixer Testbeds must be deployed on a dedicated instance.

Update the instance and install prerequisites:

$ sudo apt-get update
$ curl -sL https://deb.nodesource.com/setup_14.x -o nodesource_setup.sh
$ sudo bash nodesource_setup.sh
$ sudo apt-get install -y nodejs
$ sudo apt-get install build-essential
$ sudo npm install forever -g

Clone the mixer back end:

git clone https://github.com/red5pro/nodejs-mixer-backend

Change directories into nodejs-mixer-backend, and install the node dependencies as follows:

npm install

Generate an SSL certificate for the server to use.

Using Let’s Encrypt

The following can be run to install Let’s Encrypt Certbot on Ubuntu (snap is included with most Ubuntu distributions by default)

1. sudo snap install core; sudo snap refresh core
2. sudo snap install –classic certbot
3. sudo ln -s /snap/bin/certbot /usr/bin/certbot

To generate the cert, run sudo certbot certonly --standalone --email <your-email> --agree-tos -d <server-fqdn> (for example: sudo certbot certonly --standalone --email myname@my-email.com --agree-tos -d test01.red5pro.com)

You will then need to copy the fullchain and privatekey to the cert directory of your application

sudo cp /etc/letsencrypt/live/<server-fqdn>/fullchain.pem ~/<nodejs-server>/cert/certificate.crt
sudo cp /etc/letsencrypt/live/<server-fqdn>/privkey.pem ~/<nodejs-server>/cert/privateKey.key
sudo chmod +r ~/<nodejs-server>/cert/*

Your index.js file then needs to be modified with the full path to the certificate and privateKey files (replace with the appropriate paths):

if (useSSL) {
  cert = fs.readFileSync('/home/ubuntu/serverapp/cert/certificate.crt')
  key = fs.readFileSync('/home/ubuntu/serverapp/cert/privateKey.key')
  port = 443

Launch Command

Start the Node.js server with the following command:

sudo PORT=443 SM_TOKEN=<SM-API_token> SM_HOST=https://<Hostname-of-Stream-Manager> CERT=<path-to-fullchain.pem> KEY=<path-to-private-key.pem> forever start index.js 

By default, if PORT is not specified, the WebSocket server will run on localhost:8001.