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How to use html5 websockets within sharedworkers

After checking similar questions on stackoverflow I did not find anything much helpful for what I want to do in my project. Reading and researching I successfully made the application work having multiple connections to my Ratchet PHP websocket server, but I noticed every time the user reloaded a page or opened a link in a new tab, the client websocket got disconnected and then reconnected again.
So, I wonder how to get only one persistent connection to a WebSocket Server, for multiple users, in a web application using a Sharedworker.
What I have in the client side is this:
<script>
$(document).ready(function($) {
let socket = new WebSocket("ws://realtime:8090");
socket.onopen = function(e) {
console.log("Browser client connected to websocket server");
socket.send("Greetings from the browser!");
};
socket.onmessage = function(event) {
console.log('Data received from server: ' + event.data);
};
socket.onclose = function(event) {
if (event.wasClean) {
console.log(`Connection closed cleanly, code=${event.code} reason=${event.reason}`);
}
else {
// e.g. server process killed or network down
// event.code is usually 1006 in this case
console.log('Connection closed unexpectedly.');
}
};
socket.onerror = function(error) {
alert(error.message);
};
});
</script>

Ok after reading, researching and trying different things and code samples, I came to this solution:
The client side (browser) should have the connection to a Sharedworker.
The sharedworker is a separated javascript file containing the core of the sharedworker and whatever other JS code that needs to be executed within it.
I first tested the sharedworker to work fine with the browser tabs, counting the number of opened tabs per user and sharing messages to one user, and then to a group of users.
Once the communication between the browser and the Sharedworker passed those tests I added the websocket code to the body of the Sharedworker JS file.
In the end, the client side (browser) looks like this:
<script>
$(document).ready(function($) {
var currentUser = "{{ Auth::user()->name }}";
let worker = new SharedWorker('worker.js');
worker.port.start();
worker.port.postMessage({
action: 'connect',
username: currentUser
});
worker.port.onmessage = function(message) {
console.log(message.data);
};
});
</script>
The Sharedworker looks like this:
// All this code is executed only once, until the onconnect() function.
//---------------------------------------------------------------------
// The array AllPorts contains objects with the format {user:<string>, port:<MessagePort>}
let AllPorts = [];
var socket = new WebSocket("ws://ssa:8090");
// Called when the WebSocket Server accepts the connection.
socket.onopen = function(e) {
//
};
// Event handler fired when the WebSocket Server sends a message to this client.
socket.onmessage = function(e) {
var message = JSON.parse(e.data);
// This loop sends a message to each tab opened by the given user.
for (var i = 0; i < AllPorts.length; i++) {
if (AllPorts[i].user == message.to) {
AllPorts[i].port.postMessage(message.msg);
}
}
};
socket.onclose = function(event) {
if (event.wasClean) {
console.log('Connection closed normally');
}
else {
console.log('Connection closed unexpectedly.');
}
};
socket.onerror = function(error) {
console.log(error.message);
};
// This event handler is fired every time a new tab is opened on the web browser.
onconnect = function(ev) {
let port = ev.ports[0];
port.onmessage = function(e) {
console.log(e.data.action);
let currentUser = e.data.username;
let userIsConnected = false;
switch (e.data.action) {
case "connect":
for (var i = 0; i < AllPorts.length; i++) {
if (AllPorts[i].user == currentUser) {
userIsConnected = true;
}
}
// Add new connected tab to AllPorts array.
AllPorts.push({user: currentUser, port: port});
if (!userIsConnected) {
// New users are added to the list of the WebSocket Server.
setTimeout(() => {
socket.send(JSON.stringify({action: 'connect', username: currentUser}));
}, 600);
}
break;
case "close":
console.log(AllPorts);
var index;
// This is also executed when the user reloads the Tab.
for (var i = 0; i < AllPorts.length; i++) {
if (AllPorts[i].port == port) {
index = i;
currentUser = AllPorts[i].user;
}
}
AllPorts.splice(index, 1);
userIsConnected = false;
// Check for any connected tab.
for (var i = 0; i < AllPorts.length; i++) {
if (AllPorts[i].user == currentUser) {
userIsConnected = true;
}
}
if (!userIsConnected) {
// User doen't have more tabs opened. Remove user from WebSocket Server.
socket.send(JSON.stringify({action: 'disconnect', username: currentUser}));
}
break;
case "notify":
// Check if given user is connected.
for (var i = 0; i < AllPorts.length; i++) {
if (AllPorts[i].user == currentUser) {
userIsConnected = true;
}
}
if (userIsConnected) {
socket.send(JSON.stringify({action: 'notify', to: currentUser, message: e.data.message}));
}
} // switch
} // port.onmessage
} // onconnect

Allow only one connection at a time in websocket

When someone connect to my websocket , I want the last opened connection to be active and close all other old connections.Every users has unique token.Following is the code I created
wss.on('connection', function connection(ws,req) {
const myURL = new URL("https://example.com"+req.url);
var token = myURL.searchParams.get('token');
ws.send("success");
exists = users.hasOwnProperty(token);
if(exists)
{
//console.log("Token exists already");
// ws.send("fail");
// ws.close();
users[token]["ws"].send("fail");
users[token]["ws"].close();
users[token] = [];
users[token]["ws"] = ws;
}
else
{
users[token] = [];
users[token]["ws"] = ws;
//console.log('connected: ' + token + ' in ' + Object.getOwnPropertyNames(users));
}
ws.on('close', function () {
delete users[token]
//console.log('deleted: ' + token);
})
});
But above code works only first time , If I open third time both 2nd and 3rd connection is live.I want to close the 2nd and keep the 3rd alive.Any help is appreciated Thank you.

You probably meant to use an object instead of array
so
users[token] = {};
instead of
users[token] = [];
I would close all other connections when a new connection comes so new connection handler is something like this
wss.on('connection', function connection(ws, req) {
const myURL = new URL("https://example.com" + req.url);
var token = myURL.searchParams.get('token');
ws.send("success");
exists = users.hasOwnProperty(token);
for(const token in users){ // close all existing connections
users[token]["ws"].send("fail");
users[token]["ws"].close();
}
if (exists) {
users[token]["ws"] = ws; // update websocket
}
else {
users[token] = {ws: ws}; // add new websocket to users
// same thing as
// users[token] = {}
// users[token]["ws"] = ws
}
}

Running node-rdkafka code in server

I'm running the below node-rdkafka code in Eclipse as Node.js application. This is the sample code from https://blizzard.github.io/node-rdkafka/current/tutorial-producer_.html
I want to run this in a test server and call from iOS Mobile application.
I knew about running node.js app in AWS.
Question I: Is there any other options to run in a free test server environment like Tomcat?
Question II: Even If I am able to run this node.js app in a server, how do i call from a mobile application? Do I need to call producer.on('ready', function(arg) (or) What function i need to call from Mobile app?
var Kafka = require('node-rdkafka');
//console.log(Kafka.features);
//console.log(Kafka.librdkafkaVersion);
var producer = new Kafka.Producer({
'metadata.broker.list': 'localhost:9092',
'dr_cb': true
});
var topicName = 'MyTest';
//logging debug messages, if debug is enabled
producer.on('event.log', function(log) {
console.log(log);
});
//logging all errors
producer.on('event.error', function(err) {
console.error('Error from producer');
console.error(err);
});
//counter to stop this sample after maxMessages are sent
var counter = 0;
var maxMessages = 10;
producer.on('delivery-report', function(err, report) {
console.log('delivery-report: ' + JSON.stringify(report));
counter++;
});
//Wait for the ready event before producing
producer.on('ready', function(arg) {
console.log('producer ready.' + JSON.stringify(arg));
for (var i = 0; i < maxMessages; i++) {
var value = new Buffer('MyProducerTest - value-' +i);
var key = "key-"+i;
// if partition is set to -1, librdkafka will use the default partitioner
var partition = -1;
producer.produce(topicName, partition, value, key);
}
//need to keep polling for a while to ensure the delivery reports are received
var pollLoop = setInterval(function() {
producer.poll();
if (counter === maxMessages) {
clearInterval(pollLoop);
producer.disconnect();
}
}, 1000);
});
/*
producer.on('disconnected', function(arg) {
console.log('producer disconnected. ' + JSON.stringify(arg));
});*/
//starting the producer
producer.connect();

First of all, you need an HTTP server. ExpressJS can be used. Then, just tack on the Express code basically at the end, but move the producer loop into the request route.
So, start with what you had
var Kafka = require('node-rdkafka');
//console.log(Kafka.features);
//console.log(Kafka.librdkafkaVersion);
var producer = new Kafka.Producer({
'metadata.broker.list': 'localhost:9092',
'dr_cb': true
});
var topicName = 'MyTest';
//logging debug messages, if debug is enabled
producer.on('event.log', function(log) {
console.log(log);
});
//logging all errors
producer.on('event.error', function(err) {
console.error('Error from producer');
console.error(err);
});
producer.on('delivery-report', function(err, report) {
console.log('delivery-report: ' + JSON.stringify(report));
counter++;
});
//Wait for the ready event before producing
producer.on('ready', function(arg) {
console.log('producer ready.' + JSON.stringify(arg));
});
producer.on('disconnected', function(arg) {
console.log('producer disconnected. ' + JSON.stringify(arg));
});
//starting the producer
producer.connect();
Then, you can add this in the same file.
var express = require('express')
var app = express()
app.get('/', (req, res) => res.send('Ready to send messages!'))
app.post('/:maxMessages', function (req, res) {
if (req.params.maxMessages) {
var maxMessages = parseInt(req.params.maxMessages);
for (var i = 0; i < maxMessages; i++) {
var value = new Buffer('MyProducerTest - value-' +i);
var key = "key-"+i;
// if partition is set to -1, librdkafka will use the default partitioner
var partition = -1;
producer.produce(topicName, partition, value, key);
} // end for
} // end if
}); // end app.post()
app.listen(3000, () => console.log('Example app listening on port 3000!'))
I don't think the poll loop is necessary since you don't care about the counter anymore.
Now, connect your mobile app to http://<your server IP>:3000/ and send test messages with a POST request to http://<your server IP>:3000/10, for example, and adjust to change the number of messages to send

I might be late on this but this is how I did using promises and found it better than have a time out etc.
const postMessageToPublisher = (req, res) => {
return new Promise((resolve, reject) => {
producer.connect();
producer.setPollInterval(globalConfigs.producerPollingTime);
const actualBody = requestBody.data;
const requestBody = req.body;
const topicName = req.body.topicName;
const key = requestBody.key || uuid();
const partition = requestBody.partition || undefined;
const data = Buffer.from(JSON.stringify(udpatedBody));
/**
* Actual messages are sent here when the producer is ready
*/
producer.on(kafkaEvents.READY, () => {
try {
producer.produce(
topic,
partition,
message,
key // setting key user provided or UUID
);
} catch (error) {
reject(error);
}
});
// Register listener for debug information; only invoked if debug option set in driver_options
producer.on(kafkaEvents.LOG, log => {
logger.info('Producer event log notification for debugging:', log);
});
// Register error listener
producer.on(kafkaEvents.ERROR, err => {
logger.error('Error from producer:' + JSON.stringify(err));
reject(err);
});
// Register delivery report listener
producer.on(kafkaEvents.PUBLISH_ACKNOWLEDGMENT, (err, ackMessage) => {
if (err) {
logger.error(
'Delivery report: Failed sending message ' + ackMessage.value
);
logger.error('and the error is :', err);
reject({ value: ackMessage.value, error: err });
} else {
resolve({
teamName: globalConfigs.TeamNameService,
topicName: ackMessage.topic,
key: ackMessage.key.toString()
});
}
});
});
};
Please note that kafkaEvents contains my constants for the events we listen to and it is just a reference such as kafkaEvents.LOG is same as event.log
and also the calling function is expecting this to a promise and accordingly we user .then(data => 'send your response to user from here') and .catch(error => 'send error response to user
this is how I achieved it using promises

React Native Websocket outside access

Im trying to send an answer to my websocket-server from a component which does not contain the websocket. My Websocket server looks like this:
componentDidMount() {
var ws = new WebSocket('ws:// URL');
ws.onmessage = this.handleMessage.bind(this);
...
}
How can I pass the "var ws" to another class or component. Or is it possible to make the websocket globally accessable?
Thank you very much for any help!

I found a solution with help from this question in stackoverflow:
visit:
React native: Always running component
I created a new class WebsocketController like this:
let instance = null;
class WebsocketController{
constructor() {
if(!instance){
instance = this;
}
this.ws = new WebSocket('ws://URL');
return instance;
}
}
export default WebsocketController
And then in my other class where I need my websocket I just called it like this:
let controller = new WebsocketController();
var ws = controller.ws;
 

websocket connection
keep this code in some file, name it with .js extenstion. ex: websocket.js
var WebSocketServer = require("ws").Server;
var wss = new WebSocketServer({port:8100});
wss.broadcast = function broadcast(msg) {
console.log(msg);
wss.clients.forEach(function each(client) {
client.send(msg);
});
};
wss.on('connection', function connection(ws) {
// Store the remote systems IP address as "remoteIp".
var remoteIp = ws.upgradeReq.connection.remoteAddress;
// Print a log with the IP of the client that connected.
console.log('Connection received: ', remoteIp);
ws.send('You successfully connected to the websocket.');
ws.on('message',wss.broadcast);
});
In your app/website side. create .js file. Ex: client.js
var SERVER_URL = 'ws://127.0.0.1:8100';
var ws;
function connect() {
//alert('connect');
ws = new WebSocket(SERVER_URL, []);
// Set the function to be called when a message is received.
ws.onmessage = handleMessageReceived;
// Set the function to be called when we have connected to the server.
ws.onopen = handleConnected;
// Set the function to be called when an error occurs.
ws.onerror = handleError;
}
function handleMessageReceived(data) {
// Simply call logMessage(), passing the received data.
logMessage(data.data);
}
function handleConnected(data) {
// Create a log message which explains what has happened and includes
// the url we have connected too.
var logMsg = 'Connected to server: ' + data.target.url;
// Add the message to the log.
logMessage(logMsg)
ws.send("hi am raj");
}
function handleError(err) {
// Print the error to the console so we can debug it.
console.log("Error: ", err);
}
function logMessage(msg) {
// $apply() ensures that the elements on the page are updated
// with the new message.
$scope.$apply(function() {
//Append out new message to our message log. The \n means new line.
$scope.messageLog = $scope.messageLog + msg + "\n";
});
}
Please let me know if you face any issue with this code

Websockets: send messages and notifications to all clients except sender

I am developing chat based on websockets and webrtc. I would like to send messages to all connected users except sender but I cannot find suitable solution. To be more specific, I would like to send notifications to other connected users that new user has joined to the chat.
I am trying to give a unique ID to every connected user, but the first assigned ID is re-writed by every new user and I cannot diferentiate users.
Server:
// list of users
var CLIENTS=[];
var id;
// web server is using 8081 port
var webSocketServer = new WebSocketServer.Server({ port: 8081 });
// check if connection is established
webSocketServer.on('connection', function(ws) {
id = Math.random();
CLIENTS[id] = ws;
CLIENTS.push(ws);
ws.on('message', function(message) {
console.log('received: %s', message);
var received = JSON.parse(message);
if(received.type == "login"){
ws.send(message); // send message to itself
/* *********************************************************** */
/* *** Here I trying to check if message comes from sender *** */
sendNotes(JSON.stringify({
user: received.name,
type: "notes"
}), ws, id);
/* *********************************************************** */
}else if(received.type == "message"){
sendAll(message); // broadcast messages to everyone including sender
}
});
ws.on('close', function() {
console.log('user ' + CLIENTS[ws] + ' left chat');
delete CLIENTS[ws];
});
});
function sendNotes(message, ws, id) {
console.log('sendNotes : ', id);
if (CLIENTS[id] !== ws) {
console.log('IF : ', message);
for (var i = 0; i < CLIENTS.length; i++) {
CLIENTS[i].send(message);
}
}else{
console.log('ELSE : ', message);
}
}
function sendAll(message) {
for (var i=0; i < CLIENTS.length; i++) {
CLIENTS[i].send(message); // broadcast messages to everyone including sender
}
}
Client:
loginButton.addEventListener("click", function(){
name = usernameInput.value;
if(name.length > 0){
socket.send(JSON.stringify({
type: "login",
name: name
}));
}
});
function sendData() {
var data = dataChannelSend.value;
var userName = document.getElementById('greetingUser').innerHTML;
socket.send(JSON.stringify({
username : userName, // fetch user name from browser, after login
type : "message",
message : data
}));
}
socket.onmessage = function(message) {
var envelope = JSON.parse(message.data);
switch(envelope.type) {
case "login":
onLogin(envelope);
break;
case "message":
showMessage(envelope);
break;
}
};
I would highly appreciate If you could give me any hint. Thanks

Here is a very simple way of sending to everyone connected except the sender.
Create a broadcast function on your webSocketServer instance that will
take two params.
...
var webSocketServer = new WebSocketServer.Server({ port: 8081 });
...
/*
* method: broadcast
* #data: the data you wanna send
* #sender: which client/ws/socket is sending
*/
webSocketServer.broadcast = function(data, sender) {
webSocketServer.clients.forEach(function(client) {
if (client !== sender) {
client.send(data)
}
})
}
...
// On your message callback.
ws.on('message', function(message) {
...
// Note that we're passing the (ws) here
webSocketServer.broadcast(message, ws);
})
That's it, the broadcast method will send to each connected client
except the one who is sending.

Ok, so we are now storing the CLIENTS in a way that allows us to uniquely identify each client that is connecting, and store arbitrary information about them for later retrieval.
The code below will send the "notes" message to all clients, and THEN add the newly connecting client to the "all clients" list.
SERVER.JS:
var http = require('http'),
Static = require('node-static'),
WebSocketServer = new require('ws'),
// list of users
/*
We are now storing client data like this:
CLIENTS = {
uniqueRandomClientID: {
socket: {}, // The socket that this client is connected on
clientDetails: { // Any details you might wish to store about this client
username: "",
etc: "etc"
}
}
};
So now to get at the socket for a client, it'll be: CLIENTS[uniqueRandomClientID].socket.
Or to show a client's username, it'll be: CLIENTS[uniqueRandomClientID].clientDetails.username.
You might want to write a 'getClientByUsername' function that iterates the CLIENTS array and returns the client with that username.
*/
CLIENTS = {},
// web server is using 8081 port
webSocketServer = new WebSocketServer.Server({ port: 8081 });
// check if connection is established
webSocketServer.on('connection', function(ws) {
console.log('connection is established');
// Now using a randomly generated ID to reference a client. Probably should be better than Math.random :D
var wsID = Math.floor(Math.random() * 1000);
ws.on('message', function(message) {
console.log('received: %s', message);
var received = JSON.parse(message);
if(received.type == "login"){
// If a client with this login name doesnt exist already, its a new client
if(!CLIENTS[wsID]) {
doBroadcast(
{
"newuser": received.name,
type: "notes"
}
);
// Now add this new client to the list
CLIENTS[wsID] = {
socket: ws,
clientDetails: {
username: received.name
}
};
}
} else if(received.type == "message") {
doBroadcast(message); // broadcast messages to everyone including sender
}
});
ws.on('close', function(_event) {
if(CLIENTS[wsID]) {
console.log('user ' + CLIENTS[wsID].clientDetails.username + ' left chat');
delete CLIENTS[wsID];
}
});
/*
* Added this to 'catch' errors rather than just red dump to console. I've never actually done anything with this myself (I *like* red text in my console), but I know this handler should be here :P
*/
ws.on('error', function(_error) {
console.log("error!");
console.log(_error);
});
/*
* Send an object to a client
*
* #param WebSocketClient _to - The client you want to send to (generally an index in the CLIENTS array, i.e CLIENTS["bobsusername123"]
* #param Object _message - A stringifyable JSON object. Complex ones can screw things up, but your basic key/value pairs are usually fine to send.
*/
function doSend(_to, _message) {
_to.send(JSON.stringify(_message));
};
// Added broadcast function to replace sendAll
// Notice how it JSON stringifies the data before sending
/*
* Broadcast a message to all clients
*
* #param Object _message - A stringifyable JSON object. Complex ones can screw things up, but your basic key/value pairs are usually fine to send.
*/
function doBroadcast(_message) {
for(var client in CLIENTS) {
if(!CLIENTS.hasOwnProperty(client)) continue;
doSend(CLIENTS[client].socket, _message);
}
};
});
var fileServer = new Static.Server('.');
http.createServer(function (req, res) {
fileServer.server(req, res);
}).listen(8080, function(){
console.log("Server is listening 8080 port.");
});
console.log("Server is running on 8080 and 8081 ports");
MY CLIENT.JS (for your reference):
var loginButton = document.getElementById("loginbutton"),
usernameInput = document.getElementById("usernameInput");
var SocketClient = function(_uri, _callbacks) {
this.uri = _uri;
this.callbacks = _callbacks;
};
SocketClient.prototype = {
send: function(_message) {
this.socket.send(_message);
},
connect: function() {
try {
this.socket = new WebSocket("ws://" + this.uri);
} catch(e) { return false; }
for(var callback in this.callbacks) {
if(!this.callbacks.hasOwnProperty(callback)) continue;
this.socket["on" + callback] = this.callbacks[callback];
}
return true;
}
};
var socketClient = new SocketClient(
"127.0.0.1:8081",
{
open: function() {
console.log("connected.");
},
message: function(_message) {
console.log("received data:");
console.log(_message);
},
close: function() {
console.log("closed.");
},
error: function(_error) {
console.log("error: ");
console.log(_error);
}
}
);
socketClient.connect();
loginButton.addEventListener("click", function(){
name = usernameInput.value;
if(name.length > 0){
socketClient.send(JSON.stringify({
type: "login",
name: name
}));
}
});
AND THE CLIENT.HTML TO GO WITH IT:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
</head>
<body>
<input type="text" id="usernameInput"/>
<button type="button" id="loginbutton">Login</button>
<script src="client.js"></script>
</body>
</html>
Ive tested this with NWJS v0.12.3 running the server and Firefox on the client.

This should work
const WebSocket = require('ws');
// Websocket variables
const wss = new WebSocket.Server({
port: 3000
});
console.log('Websocket active on port 3000...');
// New WebSocket Connection
wss.on('connection', function connection(ws) {
console.log('new connection')
// On Message Received
ws.on('message', function incoming(message) {
console.log(message)
// Send To Everyone Except Sender
wss.clients.forEach(function(client) {
if (client !== ws) client.send(message);
});
});
});