How to reconnect when a WebSocket disconnects?

Question

How to reconnect when a WebSocket disconnects?

Example:

var WebSocket = require('ws');
var ws = new WebSocket('ws://echo.websocket.org/', {protocolVersion: 8, origin: 'http://websocket.org'});
ws.on('open', function() {
    console.log('connected');
    ws.send(Date.now().toString(), {mask: true});
});
ws.on('close', function() {
    console.log('disconnected');
    // What do I do here to reconnect?
});

What should I do when the socket closes to reconnect to the server?

node.js
websocket

Answer 1

You can wrap all your setup in a function and then call it from the close handler:

var WebSocket = require('ws');
var openWebSocket = function() {
    var ws = new WebSocket('ws://echo.websocket.org/', {protocolVersion: 8, origin: 'http://websocket.org'});
    ws.on('open', function() {
        console.log('connected');
        ws.send(Date.now().toString(), {mask: true});
    });
    ws.on('close', function() {
        console.log('disconnected');
        openWebSocket();
    });
}
openWebSocket();

However, there is likely more logic you want here (what if the close was on purpose? what happens if you try to send a message while its reconnecting?). You're probably better off using a library. This library suggested by aembke in the comments seems reasonable. socket.io is not a bad choice (and it gives you non-WebSocket transports).