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

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.

Related

Emit event to websocket from http request handler

Using ws for NodeJS.
const wss = new WebSocket.Server({ port: 8001 });
wss.on('connection', function connection(ws) {
ws.on('message', function incoming(message) {
console.log('received: %s', message);
});
ws.send('{"message":"something"}');
});
Connection from the client works great.
var connection = new WebSocket('ws://localhost:8001');
connection.onopen = function(){
console.log("opened");
var msg = "client message";
connection.send(msg);
}
This is logged as expected by the message handler on the NodeJS server.
I am then making a post request from another server to the endpoint relay, set up like this (this part of the NodeJS server running on express):
const app = express();
app.post('/relay', (request, response) =>{
console.log("relay hit.");
wss.emit('message', 'server message');
console.log("test message sent probably");
response.send({ result: 'OK', message: 'good hits' });
});
const server = http.createServer(app);
server.listen(8000, () => console.log('Listening on http://localhost:8000'));
The calling application gets the good response.
The problem is that wss.emit doesn't trigger the on('message') callback. wss.send throws a "not a function" error. I'm imagining this is a scope issue, but I'm not sure, and haven't been able to figure out what scope or object I would actually need if it is.
How does one trigger an event for the WebSocket Server internally? The only place I can even find emit in the docs is here and it's not explained at all.

Why Client says CONNECTED whereas the SERVER does not say so in NODE JS?

Details Regarding SERVER and CLIENT.
socket.io on server side (NODEJS)
socket.io-client on client side (also in NODEJS)
Nothing is logged on the SERVER side, as the server never lets the client connect to itself.
Whereas on the CLIENT side I see this output:
'I HAVE CONNECTED.'
SERVER CODE:
var io = require('socket.io')(server);
io.use(function(socket, next){
if (socket.handshake.query.user === "admin") {
console.log("CALLED BEFORE CONNECTION........ :)");
return next();
}
return next(new Error('Authentication error'));
});
io.on('connection', function(socket) {
console.log('CLIENT HAS CONNECTED.');
});
CLIENT CODE:
var io = require('socket.io-client');
var socket = io.connect('http://localhost:5000', { query: "user=admin11" });
socket.on('connect', function (socket) {
console.log('I HAVE CONNECTED.');
});

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.

How to connect two node.js servers with websockets?

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.

Socket.io Error (socket.send is not a function)

I'm trying out Websockets/Node.js/Socket.io/Express for the first time and I'm trying to create a simple chat program. Everything runs fine and I see both clients in my node termial.
But when I try to execute my socket.send(), I get an error in Firefox (socket.send is not a function). It doesn't complain about socket.connect() so I know the socket.io.js is loaded.
Here is my server code:
var sys = require('util');
var express = require('express');
var io = require('socket.io');
var app = express.createServer();
app.listen(8080);
app.use(express.static(__dirname));
app.get('/', function (req, res) {
res.render('index.html', {
title: 'Chat'
});
});
var socket = io.listen(app);
socket.on('connection', function (client) {
client.on('message', function (message) {
console.log("Message: " + JSON.stringify(data));
socket.broadcast(message);
});
client.on('disconnect', function () {});
});
My client code:
<script src="http://localhost:8080/socket.io/socket.io.js"></script>
var socket = new io.Socket("http://localhost:8080");
socket.connect();
Then I do some code to get the chat message and send it.
socket.send(JSON.stringify(values));
Explanations
You haven't initialized Socket.io correctly on the server-side and client-side.
Client Side
new io.Socket("http://localhost:8080"); doesn't give you the object that you want, you need new io.connect("http://localhost:8080");.
You need to wait until the client is connected to the server before sending a message.
Server side
socket is the object send back by Socket.IO, you need to use socket.sockets to have access to on.
To broadcast a message, you need to use the client object like this: client.broadcast.send()
The variable data doesn't exist on your broadcast. You probably mean message.
Solution
Server
var sys = require('util'),
express = require('express'),
io = require('socket.io'),
app = express.createServer();
app.listen(8080);
app.use(express.static(__dirname));
app.get('/', function (req, res) {
res.render('index.html', {
title: 'Chat'
});
});
var io = io.listen(app);
io.sockets.on('connection', function (client) {
client.on('message', function (message) {
console.log("Message: " + JSON.stringify(message));
client.broadcast.send(message);
});
client.on('disconnect', function () {});
});
Client
<script src="http://localhost:8080/socket.io/socket.io.js"></script>
<script>
var socket = new io.connect("http://localhost:8080"),
connected = false;
socket.on('connect', function () {
connected = true;
});
// Use this in your chat function.
if (connected) {
socket.send(JSON.stringify(values));
}
</script>
socket.broadcast(message); should be io.sockets.emit('key', message);
when you use the socket object passed in threw the connect event your only emitting information to that client, to emit to all clients you have to use io.sockets.emit().
also with socket.send(JSON.stringify(values)); I think you want to do socket.emit(namespace, data);
see my connection file from one of my projects here: https://github.com/AdminSpot/HangoutCanopy/blob/master/javascripts/connection.js
You have to wait for socket.io to connect on the client side
var socket = new io.Socket("http://localhost:8080");
socket.connect();
socket.on('connect', function() {
socket.emit('event', data);
});

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