node.js / socket.io - keep track of clients

Question

Dear friends I have a small issue while trying to keep track of a logged in users in chat. The chat is based on two separate channels that work with the help of namespaces:

1. chatInfra - to handle logged in users and send welcome messages.
2. chatCom - to handle messageing between users.

I have searched a lot but I found only theoretical explanations that the best solutions is to store users into array. Therefore I tried to keep the track of logged in users by storing them in array and then iterating through them but still the result is not good.

The problem is that after entering to the chat, only the first logged in user's name appears on screen, whereas the second user's name is not visible.

This is my server side code, I am trying to store users into clients array:

    var clients = [];

    var chatInfra = io.of("/chat_infra").on("connection", function(socket){
        socket.on("set_name", function (data) {
          clients.push(data.name);
          socket.emit('name_set', data);
          socket.send(JSON.stringify({
             type:'serverMessage',  
             message:'Welcome!' 
         }));
        socket.broadcast.emit('user_entered', data);
        });
    });

    var chatCom = io.of("/chat_com").on("connection", function (socket) {
        socket.on('message', function (message) {
            message = JSON.parse(message);
            for(var key in clients){

               if(message.type == "userMessage"){
                  message.username = clients[key];
                  console.log('message : ', message);
                  socket.broadcast.send(JSON.stringify(message));
                  message.type = "myMessage";
                  socket.send(JSON.stringify(message));
               }
            }

        });
    });

Here is how it looks in browser: http://screencast.com/t/lshnfcGZ8E8

Here is the full code: https://gist.github.com/johannesMatevosyan/0b9f7e588338dbb6b7f5

Answer 1

I think you're creating an unnecessary overkill by using different namespaces. Here's a clearer working example achieving the same functionality:

server.js

var app    = require("express")();
var server = require("http").Server(app);
var io     = require("socket.io")(server);

var chat = io.of("/chat").on("connection", function(socket){

    socket.on("set_name", function (data) {

        socket.username = data.name;

        socket.emit("name_set", data);
        socket.emit("message", {
            type    :"serverMessage",
            message :"Welcome!" 
        });
        chat.emit("message", {
            type    :"serverMessage",
            message : data.name + " has joined the room.!"
        });
    });

    socket.on("message", function (message) {
        message.username = socket.username;
        chat.emit("message", message);
    });
});


app.get("/", function (req, res) {
    res.sendfile(__dirname + "/index.html");
});

server.listen(3000);

client.js

var socket = io.connect('http://localhost:3000/chat');

socket.on('name_set', function (data) {
    $('#nameform').hide();
    $('#messages').append('<div class="systemMessage">Hello ' + data.name + '</div>');
});

socket.on('message', function (message) {
    var userNameHtml = message.username ? '<span class="name">' + message.username + ':</span>' : '';
    $('#messages').append('<div class="' + message.type + '">' + userNameHtml + message.message + '</div>');
});

$(function () {

    $('#setname').click(function () {
        socket.emit("set_name", { name: $('#nickname').val() });
    });

    $('#send').click(function () {
        socket.emit("message", {
            message : $('#message').val(),
            type    : 'userMessage'
        });
        $('#message').val('');
    });
});

I don't think you need a separate event handler for user_entered, since you are treating it as a regular message and not doing anything else with the event. Also a couple of things:

• You don't need to first connect to the server and then to the namespace address, connecting to the later is just fine.
• Don't set event listeners within callbacks, that will result in setting them multiple times.