WebSocket Server Applications

Now that you know how to use WebSockets on the client, it’s time to learn how to use WebSockets on the server. To enable support for WebSockets on the server, you’ll use the ws npm package, a WebSocket server implementation for use with Node.js applications.

The ws package provides both a server and a client implementation. The client implementation is only intended for use on Node.js, to enable server to server WebSocket connections. When reading the documentation for the ws package, focus on the following server examples:

• Simple Server
• Server Broadcast
• Example Application: Server Stats
• Example Application: Express Session Parse

After reading the documentation for the ws package, you should be able to:

• Use the ws package to create a standalone WebSocket server;
• Use the ws package to create a WebSocket server that shares a Node.js http server with an Express application;
• Create an connection event handler listener method to detect when a client has connected to the WebSocket server;
• Create an close event handler listener method to detect when a client has closed the connection to the WebSocket server; and
• Use the WebSocket send() method to send a message to a client.