Develop Reference

How to keep track of sockets in nodejs?

I am trying to keep track of all tcp connections that are made in my server and store it in an array.
My problem begins when some connection is closed, in this situation I should delete it from my array but I can't do it. Can anyone help me? How do I delete a socket that is stored in my array?
var net = require("net");
function Server(port) {
var self = this;
this.conections = [];
this.server = net.createServer(function(socket) {
self.conections.push(socket); //storing the socket in the array
})
this.server.listen(port);
console.log("TCP Server created on port: "+ port);
}
module.exports = Server;

After thinking for a while I realized that I could give an ID to each socket, this way I can monitor each new connection in an array and delete it in case the connection is lost.
var net = require("net");
function Server(port) {
var self = this;
this.connections = [];
this.connectionsId = 0;
this.server = net.createServer(function(socket) {
socket.id = self.connectionsId++;
self.connections.push(socket); //storing the socket in the array
})
//Event that is always trigger when the connection is ended
socket.on('close', function() {
self.connections = self.connections.filter(function(conn) {
return conn.id !== socket.id;
});
});
this.server.listen(port);
console.log("TCP Server created on port: "+ port);
}
module.exports = Server;
Hope it helps somebody!

Cannot connect or emit to Amazon ECS Socket.io Server via Socket.io from a HTML file located in S3 bucket

I am having trouble connecting and emitting to an ECS Fargate Socket.io Server on AWS via Socket.io from a HTML file located in a S3 bucket in the same AWS region.
The ECS Fargate Server's code is as follows:
var app = require('express')();
var http = require('http').createServer(app);
var io = require('socket.io')(http);
var AWS = require ('aws-sdk');
io.on('connect', function (socket){
console.log('connection made');
socket.on('disconnect', function (socketds) {
console.log("***********************************************");
console.log("Disconnected");
});
socket.on('reconnect', function (socketds) {
console.log("***********************************************");
console.log("Reconnected");
});
socket.on('c_status', function () {
console.log("*********************************************");
console.log("cstatus");
});
socket.on('app_message', function (mdata) {
console.log("***********************************************");
console.log("App-message:",mdata);
socket.emit('command1',mdata);
});
});
http.listen(3000, function () {
console.log('listening on *:3000');
});
And the relevant code of the HTML file is as follows:
<script>
const serverLocation = "http://application-load-balancer-dns-link:3000";
const socket = io(serverLocation);
function sendmsg() {
var date = new Date();
date.setHours(date.getHours() + 4);
var datetm = date.toISOString().split('.')[0]+"Z";
var node_id = $('#innode').val();
var clid = "0";
var msg = $('#message').val();
if (node_id.length === 1) {
var unitcode = "0" + "0" + node_id;
}
else if (node_id.length === 2) {
var unitcode = "0" + node_id;
}
else {
var unitcode = node_id;
}
var mdata = datetm+unitcode+msg;
socket.emit('app_message',mdata);
}
</script>
I have been at it for 2 days now and have not been able to figure it out. It just doesn't connect.
Any help is greatly appreciated.
If you need more information, please let me know.

1) Try checking the inbound rules of the security group associated with that instance.
2) Outbound rules should also be configured as its bidirectional (By Default allows all)
3) If they are perfect. Check whether timeout occurs or any other exception.

Node JS and Socket IO

I'm trying to write an object with member functions for receiving and sending data to and from the client with Node JS and Socket IO. The problem is that every time I send data from the client, there is a new 'connection' event that fires. Is that how it works? I thought the connection event would only occur on a new connection. So with the code below, the log echoes 'New connection' with every reception from the client. It doesn't seem right.
io.sockets.on('connection', function (socket) {
console.log('New connection');
var localSocket = socket;
var newsock = new UserSocket(localSocket);
newsock.game = null;
newsock.host = null;
newsock.opponent = null;
newsock.room = "";
newsock.SendToHostSocket('Welcome to Baseball Strategy II');
arrSockets.push(socket);
});
function UserSocket(sock) {
var localSock = sock;
var o = this;
this.sock = localSock;
this.sock.on('clientData', function (data) {
console.log("user socket object");
console.log(o);
o.ParseClientData(data);
});
}
This is a simplified version of what I have for the client:
$(document).ready( function () {
var socket = io.connect('http://local.baseball.com:3333');
function SocketGameOut(outstring) {
socket.emit('clientData', outstring );
}
$("#hostGame").click( function () {
var gamenum = $('input[name=gameSelect]:checked', '#gameForm').val();
var aSendData = { command : "newgame" , senddata : { gameid : gamenum } };
var senddata = JSON.stringify(aSendData);
SocketGameOut(senddata);
});
});

Modify your code as below it worked for me.
//use once.('connection') instead of on.('connection')
io.sockets.once('connection', function (socket) {
console.log('New connection');
var localSocket = socket;
var newsock = new UserSocket(localSocket);
newsock.game = null;
newsock.host = null;
newsock.opponent = null;
newsock.room = "";
newsock.SendToHostSocket('Welcome to Baseball Strategy II');
arrSockets.push(socket);
});

Using Node.js to retrieve data from Redis through an AJAX request

I'm going through a Node, Express, & Socket.io chat tutorial. I decided to use Redis to store the chat history and have successfully set it up so that my information is correctly posting to the database. I am now trying to access that information to use on the client-side (in this case I'm trying to access the list of users currently in the chat so I can show them to the side of the chat). I am using $.getJSON to make a GET request. Right now I have it setup so that the file it tries to access only has this JSON object : {"dog" : "2","cat":"3"} just to test it, and that is working, but I'm not sure where to go from there because anytime I try adding a function into that file, even if I specify to return a JSON object and call that function, the request stops returning the correct information.
For example I tried :
var data = function(){
return {"dog" : "2","cat":"3"}
}
data();
and that doesn't return anything ( I understand that when I make a GET request the function isn't run, but it doesn't even return that text, and if it doesn't run a function than I'm not sure how I can access redis from this file)
Here's what I'm thinking:
var redis = require('redis')
//figure out how to access the redis client that I have at localhost:6379, something like var db = redis.X
//and then call (for example) db.smembers('onlineUsers') and be returned the object which I can iterate through
Here's my relevant code:
server.js:
var jade = require('jade');
var PORT = 8080;
var redis = require('redis');
var db = redis.createClient();
var pub = redis.createClient();
var sub = redis.createClient();
var http = require('http');
var express = require('express');
var app = express();
var server = http.createServer(app);
var io = require('socket.io').listen(server);
server.listen(PORT, function(){
console.log("Now connected on localhost:" + PORT)
});
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.set("view options", {layout: false});
app.use(express.static(__dirname + '/public'));
app.get('/', function(req, res){
res.render('home');
});
io.sockets.on('connection', function(client){
sub.subscribe("chatting");
sub.on("message", function (channel, message) {
console.log("message received on server from publish");
client.send(message);
});
client.on("sendMessage", function(msg) {
pub.publish("chatting",msg);
});
client.on("setUsername", function(user){
pub.publish("chatting","A new user in connected:" + user);
db.sadd("onlineUsers",user);
}
);
client.on('disconnect', function () {
sub.quit();
pub.publish("chatting","User is disconnected :" + client.id);
});
});
script.js:
$(document).ready( function(){
$client = io.connect();
initialize();
});
var setUsername = function(){
var username = $("#usernameInput").val();
if (username)
{
var user = username;
$client.emit('setUsername', username);
$('#chatControls').show();
$('#usernameInput').hide();
$('#usernameSet').hide();
showCurrentUsers();
}
}
var showCurrentUsers = function(){
$('#list_of_users').empty();
$.getJSON('getusers.js', function(data){
for (var i = 0; i < data.length; i++){
$('list_of_users').append("<li>"+data[i]+"</li>")
}
})
}
var sendMessage = function(){
var msg = $('#messageInput').val();
var username = $("#usernameInput").val();
if (msg)
{
var data = {msg: msg, user: username}
$client.emit('message', data);
addMessage(data);
$('#messageInput').val('');
// populate(username,msg);
}
}
var addMessage = function(data) {
$("#chatEntries").append('<div class="message"><p>' + data.user + ' : ' + data.msg + '</p></div>');
}
// var populate = function(username,msg) {
// var data ;
// }
var initialize = function(){
$("#chatControls").hide();
$("#usernameSet").on('click', setUsername);
$("#submit").on('click',sendMessage);
showCurrentUsers();
}
and right now all that the getusers.js file has in it is:
{"dog" : "2","cat":"3"}

It looks like you're expecting your call to $.getJSON to load and execute the javascript it loads. It doesn't work this way. You need to make a node endpoint (via a route) which renders the JSON. The node endpoint would then do the data manipulation / querying redis:
Node:
In routes.js:
app.get('/chatdata', ChatController.getChatData);
In ChatController.js (manipulate, create the data as you like here)
exports.getChatData = function (req, res) {
var data = function(){
return {"dog" : "2","cat":"3"}
};
res.JSON(data);
};
Front-end
$.getJSON('getChatData', function(data){
//...
})

I think you need to setup a route to handle the GET request that $.getJSON makes, or if getusers.js is in the /public directory, then you need to modify your $.getJSON call as follows:
$.getJSON('http://localhost:8080/public/getusers.js', function(data){

Ok, it looks like it is a problem with your getusers.js file. $.getJSON seems to prefer double quotes. Try formatting it like this:
{
"dog" : "2",
"cat" : "3"
}
Also, try using this to display the data:
$.getJSON('getusers.js', function(data){
var items = [];
$.each( data, function( key, val ) {
items.push("<li id='" + key + "'>" + val +"</li>");
});
$('#list_of_users').append(items.join(""));
});

Socket.io Identify User for Socket

I write some code example that identifi connected users via socket.io... So now I must write a code on index page to comunicate with users.
The code is below and HOW to send a message to user[1] "Welcome" and for user[2] "HI men" and also limit connection fr 2 users. so when 2 user connected then anybody else cant connect..
Index.html:
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect();
var users;
socket.on('hello', function (data) {
console.log(data.hello);
});
socket.on('listing', function (data) {
users = data;
});
socket.on('chat', function (message) {
console.log(message);
});
socket.on('message', function (message) {
console.log(message);
});
function chat (message) {
socket.emit('chat', message);
}
function message (user, message) {
socket.emit('message', {
user: user,
message: message
});
}
</script>
app.js
var express = require('express');
var app = express.createServer();
var io = require('socket.io').listen(app);
app.listen(3000);
app.use(express.static(__dirname));
var users = {};
var userNumber = 1;
function getUsers () {
var userNames = [];
for(var name in users) {
if(users[name]) {
userNames.push(name);
}
}
return userNames;
}
io.sockets.on('connection', function (socket) {
var myNumber = userNumber++;
var myName = 'user#' + myNumber;
users[myName] = socket;
socket.emit('hello', { hello: myName });
io.sockets.emit('listing', getUsers());
socket.on('chat', function (message) {
io.sockets.emit('chat', myName + ': ' + message);
});
socket.on('message', function (data) {
users[data.user].emit('message', myName + '-> ' + data.message);
});
socket.on('disconnect', function () {
users[myName] = null;
io.sockets.emit('listing', getUsers());
});
});
app.listen(process.env.PORT);

You can start by taking a look at how to configure authorization with Socket.io. The handshakeData provided by the callback can be modified there (ie: add a username property), and any changes will be accessible via socket.handshake in your app.js (via the object passed in to the callback for io.sockets.on('connection',..). Using request header information that's also accessible from the handshakeData, you can set user values within the authorization callback (ie: from a database) so you can identify the user for the given socket in your app.js.
Here's a similar example

I know it has been a long time since you asked this, but just 4 days ago I published a module for node js, express and socket.io which manages that exactly thing you wanted. Check the Usage and Example; I hope you will find this module helpful!
You can install it via NPM socket.io.users This is a node js module for socket.io applications. One user per client.
Some of the usage code:
var express = require('express');
var app = express();
var server = require('http').createServer(app);
var socketUsers = require('socket.io.users');
// ...
socketUsers.Session(app); // IMPORTANT !
// ...
var rootIo = require('socket.io')(server); // default '/' as namespace.
var chatIo = rootIo.of('/chat');
var rootUsers = socketUsers.Users; /* default '/' as namespace.
Each namespace has ITS OWN users object list,
but the Id of a user of any other namespace may
have the same value if request comes from the same client-machine-user.
This makes easy to keep a kind of
synchronization between all users of all the different namespaces. */
var chatUsers = socketUsers.Users.of('/chat'); //
rootIo.use(socketUsers.Middleware());
/* IMPORTANT but no errors if you want
to skip it for a io.of(namespace)
that you don't want the socket.io.users' support. */
chatUsers.use(socketUsers.Middleware());
chatUsers.on('connected',function(user){
console.log(user.id + ' has connected to the CHAT');
user.store.username = 'username setted by server side'; /*at the store
property you can store any type of properties
and objects you want to share between your user's sockets. */
user.socket.on('any event', function(data){
/*user.socket is the current socket, to get all connected sockets from this
user, use: user.sockets */
});
chatIo.emit('set username',user.store.username);
});
rootUsers.on('connected',function(user){
console.log('User has connected with ID: '+ user.id);
});
rootUsers.on('connection',function(user){
console.log('Socket ID: '+user.socket.id+' is user with ID: '+user.id);
});
rootUsers.on('disconnected',function(user){
console.log('User with ID: '+user.id+'is gone away :(');
});
//...server.listen blabla..