README.md

Node.js WebSocket Server

Topic based WebSocket Server implemented in Node.js.

• Clients make connections based on the topic they are interested in
  • ws://localhost:9090?topicName=Something
• Server maintains the a map of topics vs. the subscribed connected clients
• When a client sends a message with a topic it gets pushed to all connected clients subscribed to the topic
  • Example: {"topic":"Something", "message":"Some Data"}
  • This entire JSON will be sent to all clients connected using ?topicName=Something

Getting Started

Prerequisites

NPM, Node.js, ws

Initial Steps

• Pull or download this folder
• Open cmd or powershell
• cd into the folder
• npm install

Runnning Steps

• Open cmd or powershell
• cd into the folder
• Enter node index
  • you should see started on port 9090
• Go to http://ws.truly.technology to test using WebSocket Client
  • Enter Server URL as "ws://localhost:9090?topicName=Something"
• Press Ctrl + C in the cmd or poweshell window to exit the server

---

Code Summary index.js

const WebSocket = require('ws');

const _port = 9090;
const wss = new WebSocket.Server({ port: _port }, () => {
    console.log(`started on port ${_port}`);
});

wss.on('connection', function connection(socket, req) {
  
    console.log(`USER CONNECTED: ${req.connection.remoteAddress}`);

    socket.on('message', (messagestring) => {
        console.log(`Received: ${messagestring} `);
        // Reply or do somthing
    });

    socket.on('disconnect', function () {
        console.log('USER DISCONNECTED');
    });

    socket.on('close', function () {
        console.log('USER CLOSED');
    });    

});