How to connect two node.js servers with websockets? - node.js

Here's my problem:
I have server A, running node.js and using socket.io for communicating with clients (web browsers). This all is running fine and dandy.
However, now that I have server B, which also needs to connect to server A through websockets, I have hit a wall. None of the node.js websocket clients I've found won't work with the socket.io on the server A.
So, this is the case I'm striving for:
.--------. .----------. .----------.
| CLIENT | <--> | SERVER A | <--> | SERVER B |
'--------' '----------' '----------'
Client-server A connection is done through socket.io
Now, Server B (running node.js) should connect to server A via websocket (in order to go through port 80). But...
Even the example code in socket.io-client module doesn't work... :/
// Connect to server
var socket = new io.Socket('localhost', {port: 8080});
socket.connect();
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected.');
});
The code just passes without any errors and execution ends after few seconds.
Update: Code samples
Server (which works just fine) looks like this:
// Load requirements
var http = require('http'),
io = require('socket.io');
// Create server & socket
var server = http.createServer(function(req, res){
// Send HTML headers and message
res.writeHead(404, {'Content-Type': 'text/html'});
res.end('<h1>Aw, snap! 404</h1>');
});
server.listen(8080);
io = io.listen(server);
// Add a connect listener
io.sockets.on('connection', function(socket) {
console.log('Client connected.');
// Disconnect listener
socket.on('disconnect', function() {
console.log('Client disconnected.');
});
});
Client looks like this
console.log('1');
// Connect to server
var io = require('socket.io-client')
var socket = new io.Socket('localhost', {port: 8080});
socket.connect();
console.log('2');
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected!');
});
console.log('3');
1, 2 and 3 prints out just fine, no errors, and few seconds later the process just exits
Also, server A doesn't output anything to the log, even though I have the socket.io logging set on "everything".

For future people:
Here is 2 very simple Node.js apps that use socket.io to connect, send and receive messages between each other.
Required package is:
npm install socket.io
Node-App-1 server.js:
var io = require('socket.io').listen(3000);
io.on('connection', function (socket) {
console.log('connected:', socket.client.id);
socket.on('serverEvent', function (data) {
console.log('new message from client:', data);
});
setInterval(function () {
socket.emit('clientEvent', Math.random());
console.log('message sent to the clients');
}, 3000);
});
Node-App-2 client.js:
var io = require('socket.io-client');
var socket = io.connect("http://localhost:3000/", {
reconnection: true
});
socket.on('connect', function () {
console.log('connected to localhost:3000');
socket.on('clientEvent', function (data) {
console.log('message from the server:', data);
socket.emit('serverEvent', "thanks server! for sending '" + data + "'");
});
});

Turns out I was using old examples, for some reason, even though I triple checked them. Well, doh.
Also, it turned out that the socket.io-client is broken on latest Node (6.x.x). Managed to find an update from github for it, replaced the files and yay, everything's working!
Edit: Unfortunately I didn't save any links to working examples but after quickly skimming through the code it seems that the only changes were to the client code, which now looks like this:
console.log('1');
// Connect to server
var io = require('socket.io-client')
var socket = io.connect('localhost:8080', {reconnect: true});
console.log('2');
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected!');
});
console.log('3');

Here is a snippet of code I wrote, it's using socket.io 1.0.6 and socket.io-client 1.0.6. The case is the following:
Server A (Socket.io Client) <---> Server B (Socket.io Server)
Server B (Server):
// Load requirements
var http = require('http'),
io = require('socket.io');
// Create server & socket
var server = http.createServer(function(req, res)
{
// Send HTML headers and message
res.writeHead(404, {'Content-Type': 'text/html'});
res.end('<h1>Aw, snap! 404</h1>');
});
server.listen(8080);
io = io.listen(server);
// Add a connect listener
io.sockets.on('connection', function(socket)
{
console.log('Client connected.');
// Disconnect listener
socket.on('disconnect', function() {
console.log('Client disconnected.');
});
});
Server A (Client):
console.log('1');
// Connect to server
var io = require('socket.io-client');
var socket = io.connect('http://localhost:8080', {reconnect: true});
console.log('2');
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected!');
});
console.log('3');
If I'm using localhost:8080 only on the client server it doesn't connect.

Related

How to handle io.use middleware to capture errors on client?

I need to check authentication for my socket connection and drop one if they failed. My server and client codes looks like the following;
// server.js
var http = require('http');
var sio = require('socket.io');
var app = require('express')();
var server = require('http').createServer(app).listen(3000, function () {
console.log('Server listening on 3000 port');
});
var io = sio.listen(server);
io.use(function (socket, next) {
return next(new Error('Not Authenticated'));
});
// client.js
var socket = io.connect(window.location.origin);
socket.on('connect', function () {
console.log('socket connected')
});
My problem is I can't capture Not Authenticated error on the client side to handle it and show some popup for example.
Now if Not Authenticated error get executed on server side then socket connection still persists but none of socket.emit('message') don't any work.
How can I capture this error on client side to make some decision?
You should catch error events clientside:
socket.on('error', function(err) {
console.log('The server sent an error', err);
});
2021 update: for Socket.io v3 and up, errors that get passed to middleware callbacks trigger a connect_error event client side, as documented here.

How to emit message from client side [node.js + socket.io]

I am trying to emit message from client side with socket.io ...
Here is my client code:
var socket = io.connect('http://localhost/');
socket.on('connect', function(data){
setStatus('connected');
socket.emit('subscribe', {channel:'update.comment'});
});
Server:
io.sockets.on('connection', function (socket) {
socket.emit('message', { text : 'Welcome!' });
socket.on('subscribe', function (data) {
socket.join(data.channel);
redisClient.subscribe(data.channel);
});
});
Also I get this error message in console:
GET
http://localhost/socket.io?EIO=3&transport=polling&t=1442169984269-1
404 (Not Found)
Full serever:
var app = require('express')();
var http = require('http').Server(app);
var redis = require('ioredis');
var io = require('socket.io')(http);
redisClient = redis.createClient();
//look for connection errors and log
redisClient.on("error", function (err) {
console.log("error event - " + redisClient.host + ":" + redisClient.port + " - " + err);
});
io.sockets.on('connection', function (socket) {
socket.emit('message', { text : 'Welcome!' });
//on subscription request joins specified room
//later messages are broadcasted on the rooms
socket.on('subscribe', function (data) {
socket.join(data.channel);
redisClient.subscribe(data.channel);
});
});
redisClient.on('ready', function(data) {
console.log('#redis ready');
});
redisClient.on("message", function(channel, message){
console.log(channel);
var resp = {'text': message, 'channel':channel};
io.sockets.in(channel).emit('message', resp);
});
http.listen(3000, function(){
console.log('Listening on Port 3000');
});
New Problem Recognized:
Your server is listening on port 3000, but you are attempting to connect on port 80. The error message http://localhost/socket.io?EIO=3&transport=polling&t=1442169984269-1 has no port number on it so that defaults to port 80.
That error message means that your server-side socket.io code is not initialized correctly and thus is not listening for the HTTP request that starts all webSocket connections so when the browser tries to connect on that URL to initiate a socket.io connection, there's nobody on the server-side listening so the web server returns a 404 error back to the browser.
If you are using Express, this is the minimal socket.io initialization to hook it into your server:
var express = require('express');
var app = express();
var server = app.listen(8081);
var io = require('socket.io').listen(server);
For a plain HTTP server, this is the minimal socket.io initialization:
var app = require('http').createServer(handler)
var io = require('socket.io')(app);
app.listen(80);
As always, if you show us the socket.io and web server initialization code you are using, we can help you better with your specific code issue.

Node js - Socket.io-client is not connecting to socket.io server

I am trying to connect to a socket.io-client using the following code:
Server:
// Load requirements
var http = require('http'),
io = require('socket.io');
// Create server & socket
var server = http.createServer(function(req, res){
// Send HTML headers and message
res.writeHead(404, {'Content-Type': 'text/html'});
res.end('<h1>Aw, snap! 404</h1>');
});
server.listen(8080);
io = io.listen(server);
// Add a connect listener
io.sockets.on('connection', function(socket) {
console.log('Client connected.');
// Disconnect listener
socket.on('disconnect', function() {
console.log('Client disconnected.');
});
});
Client:
console.log('1');
// Connect to server
var io = require('socket.io-client')
var socket = io.connect('localhost:8080', {reconnect: true});
console.log('2');
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected!');
});
console.log('3');
I don't get the Connected console log or Client Connected console log and I don't know why! The code sample is taken from another question posted: Link and I don't see any solution to the problem...
Use the same version of socket io client and server. It will work perfectly.
Also you need to add protocol with path.
change
var socket = io.connect('localhost:8080', {reconnect: true});
to
var socket = io.connect('http://localhost:8080', {reconnect: true});
Assuming you are using a socket.io version greater than 1.0, on the server, change this:
// Add a connect listener
io.sockets.on('connection', function(socket) {
console.log('Client connected.');
// Disconnect listener
socket.on('disconnect', function() {
console.log('Client disconnected.');
});
});
to this:
// Add a connect listener
io.on('connection', function(socket) {
console.log('Client connected.');
// Disconnect listener
socket.on('disconnect', function() {
console.log('Client disconnected.');
});
});
See the socket.io documentation reference here.
You don't want to be listening for this event only on already connected sockets. You want to listen for this event on any socket, even a newly created one.
Also, be very careful when reading socket.io code in random places on the internet. Some things changed significantly from v0.9 to v1.0 (I don't know if this was one of those things or not). You should generally always start with the socket.io documentation site first since that will always represent the latest version. Then, if looking at other internet references, make sure you only use articles that are later than mid-2014. If you don't know the vintage of an article, it's best not to rely on it without corroboration from a more recent article.
you can use localhost. It works for me as well. You must use your ip address and port that works for you

Why is my connection of a NodeJS server (Sails) to another NodeJS Server (Express4) using Socket.IO failing?

I am trying to connect my Node.JS (written using Sails.JS) app to another Node.JS server (Express4 / Socket.io) using socket.io-client.
My Sails Service app/services/Watcher.js looks like
var client = require('../../node_modules/sails/node_modules/socket.io/node_modules/socket.io-client');
// callback of the form function(socket)
exports.connect = function(callback) {
sails.log.debug("will connect socket to", sails.config.watcher.uri, "with Socket.io-client version", client.version);
var socket = client.connect(sails.config.watcher.uri);
socket.on('connect', function(){
sails.log.debug("connected");
socket.on('disconnect', function(){
sails.log.debug("Disconnected");
});
socket.on('error', function(err){
sails.log.debug("Could not connect", err);
});
callback(socket);
});
};
This is invoked from config/bootstrap.js as follows:
Watcher.connect(function(socket){
sails.log.debug("Connected watcher to relay with socket", socket);
});
On the Express side my server relay.js is as simple as:
var app = require('express')(),
http = require('http').Server(app),
io = require('socket.io').listen(http),
port = process.env.RELAY_PORT || 8000;
app.get('/', function(req, res) {
var response = {message: "some response"}; // to be implemented.
res.json(response);
});
http.listen(port, function () {
console.log("Relay listening on port " + port);
});
io.sockets.on('connection', function (socket) {
console.log("Connection opened", socket);
socket.on('disconnect', function () {
console.log("Socket disconnected");
});
});
When I run node relay it dutifully reports
Relay listening on port 8000
When I sails lift my other server it dutifully reports
will connect socket to http://localhost:8000 with Socket.io-client version 0.9.16
But I never see an actual connection.
If I point a browser at localhost:8000 I get the {"message":"some response"} JSON response I expect.
Why isn't my relay server accepting a connection from my socker.io-client app?
The issue here is probably that you're trying to re-use the
socket.io-client from inside of Sails. In general, if you're require()-ing dependencies of Sails directly in your project, you're heading in the wrong direction. In this case, socket.io-client caches configurations and connections, so your require isn't getting a fresh copy.
Instead, do
npm install socket.io-client#~0.9.16 --save
in your project and require with
var client = require('socket.io-client');
that'll give you a fresh copy of the socket client to work with, and avoid any conflicts with the Sails core's version.

Node.js client for a socket.io server

I have a socket.io server running and a matching webpage with a socket.io.js client. All works fine.
But, I am wondering if it is possible, on another machine, to run a separate node.js application which would act as a client and connect to the mentioned socket.io server?
That should be possible using Socket.IO-client: https://github.com/LearnBoost/socket.io-client
Adding in example for solution given earlier. By using socket.io-client https://github.com/socketio/socket.io-client
Client Side:
//client.js
var io = require('socket.io-client');
var socket = io.connect('http://localhost:3000', {reconnect: true});
// Add a connect listener
socket.on('connect', function (socket) {
console.log('Connected!');
});
socket.emit('CH01', 'me', 'test msg');
Server Side :
//server.js
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
io.on('connection', function (socket){
console.log('connection');
socket.on('CH01', function (from, msg) {
console.log('MSG', from, ' saying ', msg);
});
});
http.listen(3000, function () {
console.log('listening on *:3000');
});
Run :
Open 2 console and run node server.js and node client.js
After installing socket.io-client:
npm install socket.io-client
This is how the client code looks like:
var io = require('socket.io-client'),
socket = io.connect('http://localhost', {
port: 1337,
reconnect: true
});
socket.on('connect', function () { console.log("socket connected"); });
socket.emit('private message', { user: 'me', msg: 'whazzzup?' });
Thanks alessioalex.
const io = require('socket.io-client');
const socket_url = "http://localhost:8081";
let socket = io.connect(socket_url);
socket.on('connect', function () {
socket.emit("event_name", {});
});
Yes you can use any client as long as it is supported by socket.io. No matter whether its node, java, android or swift. All you have to do is install the client package of socket.io.
Client side code: I had a requirement where my nodejs webserver should work as both server as well as client, so i added below code when i need it as client, It should work fine, i am using it and working fine for me!!!
const socket = require('socket.io-client')('http://192.168.0.8:5000', {
reconnection: true,
reconnectionDelay: 10000
});
socket.on('connect', (data) => {
console.log('Connected to Socket');
});
socket.on('event_name', (data) => {
console.log("-----------------received event data from the socket io server");
});
//either 'io server disconnect' or 'io client disconnect'
socket.on('disconnect', (reason) => {
console.log("client disconnected");
if (reason === 'io server disconnect') {
// the disconnection was initiated by the server, you need to reconnect manually
console.log("server disconnected the client, trying to reconnect");
socket.connect();
}else{
console.log("trying to reconnect again with server");
}
// else the socket will automatically try to reconnect
});
socket.on('error', (error) => {
console.log(error);
});
something like this worked for me
const WebSocket = require('ws');
const ccStreamer = new WebSocket('wss://somthing.com');
ccStreamer.on('open', function open() {
var subRequest = {
"action": "SubAdd",
"subs": [""]
};
ccStreamer.send(JSON.stringify(subRequest));
});
ccStreamer.on('message', function incoming(data) {
console.log(data);
});

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