How to connect two node.js servers with websockets?
node.jssocket.ionode.js Problem Overview
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".
node.js Solutions
Solution 1 - node.js
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 + "'");
});
});
Solution 2 - node.js
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');
Solution 3 - node.js
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.