Reconnecting WebSocket
WebSocket that will automatically reconnect if the connection is closed.
Features
- WebSocket API compatible (same interface, Level0 and Level2 event model)
- Fully configurable
- Multi-platform (Web, ServiceWorkers, Node.js, React Native)
- Dependency free (does not depend on Window, DOM or any EventEmitter library)
- Handle connection timeouts
- Allows changing server URL between reconnections
- Buffering. Will send accumulated messages on open
- Multiple builds available (see dist folder)
- Debug mode
Install
npm install --save reconnecting-websocketUsage
Compatible with WebSocket Browser API
So this documentation should be valid: MDN WebSocket API.
Ping me if you find any problems. Or, even better, write a test for your case and make a pull request :)
Simple usage
import ReconnectingWebSocket from 'reconnecting-websocket';
const rws = new ReconnectingWebSocket('ws://my.site.com');
rws.addEventListener('open', () => {
rws.send('hello!');
});Update URL
The url parameter will be resolved before connecting, possible types:
string() => string() => Promise<string>
import ReconnectingWebSocket from 'reconnecting-websocket';
const urls = ['ws://my.site.com', 'ws://your.site.com', 'ws://their.site.com'];
let urlIndex = 0;
// round robin url provider
const urlProvider = () => urls[urlIndex++ % urls.length];
const rws = new ReconnectingWebSocket(urlProvider);import ReconnectingWebSocket from 'reconnecting-websocket';
// async url provider
const urlProvider = async () => {
const token = await getSessionToken();
return `wss://my.site.com/${token}`;
};
const rws = new ReconnectingWebSocket(urlProvider);Options
Sample with custom options
import ReconnectingWebSocket from 'reconnecting-websocket';
import WS from 'ws';
const options = {
WebSocket: WS, // custom WebSocket constructor
connectionTimeout: 1000,
maxRetries: 10,
};
const rws = new ReconnectingWebSocket('ws://my.site.com', [], options);Available options
type Options = {
WebSocket?: any; // WebSocket constructor, if none provided, defaults to global WebSocket
maxReconnectionDelay?: number; // max delay in ms between reconnections
minReconnectionDelay?: number; // min delay in ms between reconnections
reconnectionDelayGrowFactor?: number; // how fast the reconnection delay grows
minUptime?: number; // min time in ms to consider connection as stable
connectionTimeout?: number; // retry connect if not connected after this time, in ms
maxRetries?: number; // maximum number of retries
maxEnqueuedMessages?: number; // maximum number of messages to buffer until reconnection
startClosed?: boolean; // start websocket in CLOSED state, call `.reconnect()` to connect
debug?: boolean; // enables debug output
};Default values
WebSocket: undefined,
maxReconnectionDelay: 10000,
minReconnectionDelay: 1000 + Math.random() * 4000,
reconnectionDelayGrowFactor: 1.3,
minUptime: 5000,
connectionTimeout: 4000,
maxRetries: Infinity,
maxEnqueuedMessages: Infinity,
startClosed: false,
debug: false,API
Methods
constructor(url: UrlProvider, protocols?: string | string[], options?: Options)
close(code?: number, reason?: string)
reconnect(code?: number, reason?: string)
send(data: string | ArrayBuffer | Blob | ArrayBufferView)
addEventListener(type: 'open' | 'close' | 'message' | 'error', listener: EventListener)
removeEventListener(type: 'open' | 'close' | 'message' | 'error', listener: EventListener)Attributes
binaryType: string;
bufferedAmount: number;
extensions: string;
onclose: EventListener;
onerror: EventListener;
onmessage: EventListener;
onopen: EventListener;
protocol: string;
readyState: number;
url: string;
retryCount: number;Constants
CONNECTING 0 The connection is not yet open.
OPEN 1 The connection is open and ready to communicate.
CLOSING 2 The connection is in the process of closing.
CLOSED 3 The connection is closed or couldn't be opened.
Contributing
License
MIT