CODEWITHSUNDEEP
javascriptnode.js
torayeff
torayeff

Reputation: 9702

NodeJS events on('connect') error

Recently I have started learning Node.js with "Node.js in Action" book. In chapter there is following listing:

var events = require('events');
var net = require('net');

var channel = new events.EventEmitter();
channel.clients = {};
channel.subsriptions = {};

channel.on('join', function (id, client) {
    this.clients[id] = client;
    this.subsriptions[id] = function (senderId, message) {
        if (id !== senderId) {
            this.clients[id].write(message);
        }
    };
    this.on('broadcast', this.subsriptions[id]);
});

var server = net.createServer(function (client) {
    var id = client.remoteAddress + ':' + client.remotePort;
    client.on('connect', function () {
        channel.emit('join', id, client);
    });
    client.on('data', function (data) {
        data = data.toString();
        channel.emit('broadcast', id, data);
    });
});

server.listen(8888);

I ran code:

node chat_server.js

Then opened new terminal and connected to chat_sever:

telnet 127.0.0.1 8888

Then again opened new terminal window and connected to chat_server. The book says:

"If you open up a few command lines, you’ll see that anything typed in one command line is echoed to the others. "

I tried to type in one terminal but nothing echoed in others. What can be problem? I am running Ubuntu 12.04

EDIT:

I tried to debug this part:

client.on('connect', function () {
        console.log('joined ' + id);
        channel.emit('join', id, client);
    });

but it does not show me "joined message" even if I open several terminals.

Upvotes: 2

Views: 891

Answers (1)

torayeff
torayeff

Reputation: 9702

I have solved my problem by the help of this SO question:

on the server side, the socket is already connected when you get the callback, and the event you're trying to listen to isn't emitted on an already connected socket.

So, I emitted 'join' outside of client.on('connect'). In other words this code:

client.on('connect', function () {
        channel.emit('join', id, client);
    });

does nothing. And it must be replaced by:

channel.emit('join', id, client);

Upvotes: 3

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