Introduction to the 'reconnecting-websocket' library

If you're a programmer familiar with implementing websockets, you've probably encountered the issue of the websocket connection breaking unexpectedly. This can happen due to a variety of reasons, such as network issues or server restarts. This is where the reconnecting-websocket library comes in.

What is 'reconnecting-websocket'?

'reconnecting-websocket' is a Javascript library that provides a wrapper around the native WebSocket object to automatically reconnect to the server whenever the connection is lost. It also handles back-off strategies to prevent flooding the server with too many reconnection attempts.

Installation

You can install reconnecting-websocket via npm:

npm install reconnecting-websocket

Or, you can include it directly in your HTML file via a CDN:

<script src="https://cdn.jsdelivr.net/npm/reconnecting-websocket@4.4.0/dist/reconnecting-websocket.min.js"></script>

Usage

To use reconnecting-websocket, you need to create a new instance of the ReconnectingWebSocket class, passing in the WebSocket URL as the argument:

const socket = new ReconnectingWebSocket('ws://example.com/socket');

From here, you can use the socket just like you would with a regular WebSocket:

socket.onopen = () => {
  console.log('WebSocket connection established.');
};

socket.onmessage = (event) => {
  console.log(`Received message: ${event.data}`);
};

socket.send('Hello, server!');

Options

reconnecting-websocket provides a variety of options to customize the behavior of the library. Here are some of the most commonly used ones:

• maxReconnectionDelay - the maximum amount of time to wait between reconnection attempts (in milliseconds)
• minReconnectionDelay - the minimum amount of time to wait between reconnection attempts (in milliseconds)
• reconnectionDelayGrowFactor - the amount that the delay time increases between reconnection attempts (e.g. a value of 1.5 means that the delay time will increase by 50% with each attempt)
• connectionTimeout - the amount of time to wait for a connection to be established before retrying (in milliseconds)

const options = {
  maxReconnectionDelay: 10000,
  minReconnectionDelay: 1000,
  reconnectionDelayGrowFactor: 1.5,
  connectionTimeout: 4000,
};

const socket = new ReconnectingWebSocket('ws://example.com/socket', [], options);

Conclusion

If you're implementing websockets in your project and want to handle unexpected connection issues, reconnecting-websocket is a useful library to have in your toolbox. It provides a simple and customizable way to automatically reconnect to the server in the event of a disconnection.