Create sockettimeoutexception with node js server - node.js

So I modified the accepted answer in this thread How do I shutdown a Node.js http(s) server immediately? and was able to close down my nodejs server.
// Create a new server on port 4000
var http = require('http');
var server = http.createServer(function (req, res) { res.end('Hello world!'); }).listen(4000);
// Maintain a hash of all connected sockets
var sockets = {}, nextSocketId = 0;
server.on('connection', function (socket) {
// Add a newly connected socket
var socketId = nextSocketId++;
sockets[socketId] = socket;
console.log('socket', socketId, 'opened');
// Remove the socket when it closes
socket.on('close', function () {
console.log('socket', socketId, 'closed');
delete sockets[socketId];
});
});
...
when (bw == 0) /*condition to trigger closing the server*/{
// Close the server
server.close(function () { console.log('Server closed!'); });
// Destroy all open sockets
for (var socketId in sockets) {
console.log('socket', socketId, 'destroyed');
sockets[socketId].destroy();
}
}
However, on the client side, the client throws a ConnectionException because of the server.close() statement. I want the client to throw a SocketTimeoutException, which means the server is active, but the socket just hangs. Someone else was able to do this with a jetty server from Java
Server jettyServer = new Server(4000);
...
when (bw == 0) {
server.getConnectors()[0].stop();
}
Is it possible to achieve something like that? I've been stuck on this for a while, any help is extremely appreciated. Thanks.

What you ask is impossible. A SocketTimeoutException is thrown when reading from a connection that hasn't terminated but hasn't delivered any data during the timeout period.
A connection closure does not cause it. It doesn't cause a ConnectionException either, as there is no such thing. It causes either an EOFException, a null return from readLine(), a -1 return from read(), or an IOException: connection reset if the close was abortive.
Your question doesn't make sense.

Related

Node.js how to find and stop socket connection

I am using socket.io in one of express route to populate data from server and send it to on client with different event names, firstsocket and secondsocket.
var io
router.get('/start', function(req, res, next) {
io = req.app.get('socketio');
var socketlist = [{name:"firstsocket"},{name:"secondsocket"}]
for (var key in socketlist){
myInterval = setInterval(function(){
JsonObj.marks = socketlist[key].name+' '+parseInt(Math.random()*100);
io.emit(socketname, JsonObj);
}, 2000);
}
});
it is working and i can see the data on client console for these to socket events. Now i want to stop one of the socket event based on user button click. I am not getting idea to list and stop sockets.
router.get('/stop', function(req, res) {
if(req.socketname=='firstsocket') {
//stop and destroy firstsocket
}
if(req.socketname=='secondsocket') {
//stop and destroy secondsocket
}
res.redirect('/');
});
please suggest, how to identify and stop one socket session out of multiple sessions.
Thanks
If you store the socket.id information of each socket within your
var socketlist = [{name:"firstsocket"},{name:"secondsocket"}]; array,
then you would be able to close a socket connection by doing;
io.sockets.sockets[socketlist[req.socketname].socket_id].disconnect(true);
Though, I would recommend you to check if
io.sockets.sockets[socketlist[req.socketname].socket_id]
returns undefined before accessing it's disconnect property.
If you try to access disconnect property of an already closed socket, the code above will return undefined and you will have an error thrown saying
"Can't access the property disconnect of undefined"
Final code should be something like this;
if (io.sockets.sockets[socketlist[req.socketname].socket_id]) {
io.sockets.sockets[socketlist[req.socketname].socket_id].disconnect(true);
}
You can get the socket.id information of a socket on the initial connection to the server.
I'd advise you to move your io decleration out of the route and declare it like this with your socket list;
var io = require('socket.io')(server);
var socketlist = [], first_socket_connected = false;
The server variable should be your express server.
Then, use the code below to receive socket connections and push to your socket list;
io.on("connection", function(socket) {
socketlist.push({name: first_socket_connected ? "secondsocket" : "firstsocket", id: socket.id});
first_socket_connected = true;
});

How to connect multiple socket clients nodejs

Scenario is i have a server where socket(1) runs i have one more server where socket(2) client connects to socket(1)
I have one browser socket which connects to socket(1)
Idea is to do request from browser and bring data from socket(2) server
Not sure how to difference between socket clients as all the sockets are similar to socket(1)
Ideally there will be multiple browser sockets and multiple socket(2) clients
Browser sockets can make request to any of the socket(2) clients
How to implement it using nodejs socket.io
Server
socket.on('action', (action) => {
if(action.type === 'server/hello'){
io.sockets.emit('broadcast',{ description: clients + ' clients connected!'});
console.log('Got hello data!', action.data);
}
});
Browser client
var socket = io.connect('localhost:3000', {reconnect: true});
socket.on('connect', function(data) {
socket.emit('joined', 'Hello World from client this is client plxx');
});
socket.on('response2', function(data) {
console.log("got it ", data);
$('#messages').append($('<li>').text(JSON.stringify(data)));
});
Server client
var io = require('socket.io-client');
var socket = io.connect('http://localhost:3000', {reconnect: true});
socket.on('broadcast', function (t) {
socket.emit("data", {data: 32})
console.log('broadcast! my host is est');
});
i should be able to communicate between socket clients
What I understood from your question is: you need to differentiate between sockets from different clients.
To solve that I would suggest simply emitting the socket source from the client on connect.
And on the server split the sockets into two lists.
Example:
Server
const BROWSER_CLIENTS = {};
const SERVER_CLIENTS = {};
io.on("connection", socket => {
socket.on("source", payload => {
if (payload == "browser")
BROWSER_CLIENTS[socket.id] = socket;
else if (payload == "server")
SERVER_CLIENTS[socket.id] = socket;
});
socket.on("disconnect", () => {
delete BROWSER_CLIENTS[socket.id];
delete SERVER_CLIENTS[socket.id];
});
});
Browser Client
socket.on("connect", () => {
socket.emit("source", "browser");
});
Server Client
socket.on("connect", () => {
socket.emit("source", "server");
});
Now when you receive an event you can detect from which source it originated. And if you need to send to all sockets of one type of clients you can simply do this:
Server
for (let i in BROWSER_CLIENTS)
BROWSER_CLIENTS[i].emit("Hello Browsers")
for (let i in SERVER_CLIENTS)
SERVER_CLIENTS[i].emit("Hello Servers")
EDIT: I found this link and thought you could make use of it. Socket.io Rooms

use node.js cluster with socket.io chat application

I'm trying to learn node.js cluster with socket.io to create a chat application... the problem is that I can't seem to get things working.
i've been trying to go through all the tutorials including the one that I get from this http://stackoverflow.com/questions/18310635/scaling-socket-io-to-multiple-node-js-processes-using-cluster/18650183#18650183
when I try to open two browsers, the messages does not go to the other browser.
here's the code that i got
var express = require('express'),
cluster = require('cluster'),
net = require('net'),
socketio = require('socket.io'),
socket_redis = require('socket.io-redis');
var port = 3000,
num_processes = require('os').cpus().length;
if (cluster.isMaster) {
// This stores our workers. We need to keep them to be able to reference
// them based on source IP address. It's also useful for auto-restart,
// for example.
var workers = [];
// Helper function for spawning worker at index 'i'.
var spawn = function(i) {
workers[i] = cluster.fork();
// Optional: Restart worker on exit
workers[i].on('exit', function(code, signal) {
console.log('respawning worker', i);
spawn(i);
});
};
// Spawn workers.
for (var i = 0; i < num_processes; i++) {
spawn(i);
}
// Helper function for getting a worker index based on IP address.
// This is a hot path so it should be really fast. The way it works
// is by converting the IP address to a number by removing non numeric
// characters, then compressing it to the number of slots we have.
//
// Compared against "real" hashing (from the sticky-session code) and
// "real" IP number conversion, this function is on par in terms of
// worker index distribution only much faster.
var worker_index = function(ip, len) {
var s = '';
for (var i = 0, _len = ip.length; i < _len; i++) {
if (!isNaN(ip[i])) {
s += ip[i];
}
}
return Number(s) % len;
};
// Create the outside facing server listening on our port.
var server = net.createServer({ pauseOnConnect: true }, function(connection) {
// We received a connection and need to pass it to the appropriate
// worker. Get the worker for this connection's source IP and pass
// it the connection.
var worker = workers[worker_index(connection.remoteAddress, num_processes)];
worker.send('sticky-session:connection', connection);
}).listen(port);
} else {
// Note we don't use a port here because the master listens on it for us.
var app = new express();
// Here you might use middleware, attach routes, etc.
app.use('/assets', express.static(__dirname +'/public'));
app.get('/', function(req, res){
res.sendFile(__dirname + '/index.html');
});
// Don't expose our internal server to the outside.
var server = app.listen(),
io = socketio(server);
// Tell Socket.IO to use the redis adapter. By default, the redis
// server is assumed to be on localhost:6379. You don't have to
// specify them explicitly unless you want to change them.
io.adapter(socket_redis({ host: 'localhost', port: 6379 }));
// Here you might use Socket.IO middleware for authorization etc.
io.on('connection', function(socket) {
console.log('New client connection detected on process ' + process.pid);
socket.emit('welcome', {message: 'Welcome to BlueFrog Chat Room'});
socket.on('new.message', function(message) {
socket.emit('new.message', message);
})
});
// Listen to messages sent from the master. Ignore everything else.
process.on('message', function(message, connection) {
if (message !== 'sticky-session:connection') {
return;
}
// Emulate a connection event on the server by emitting the
// event with the connection the master sent us.
server.emit('connection', connection);
connection.resume();
});
}
If I understand correctly, your problem is that the messages from a client are not broadcasted to the other clients. you can solve this easily using :
io.on('connection', function(socket) {
console.log('New client connection detected on process ' + process.pid);
socket.emit('welcome', {message: 'Welcome to BlueFrog Chat Room'});
socket.on('new.message', function(message) {
socket.emit('new.message', message); // this line sends the message back to the emitter
socket.broadcast.emit('my message', msg); // this broadcasts the message to all the clients
})
});
There are different ways to emit a message. The one you're using emits the message only to the socket that first sent a 'new.message' message to the server. Which means that a socket will receive the message that you emit there only if it first sent a message 'new.message'. That's why, in your browser, the client originating the message is the only one receiving it back.
Change it to:
socket.on('new.message', function(message) {
io.sockets.emit('new.message', message);//use this if even the browser originating the message should be updated.
socket.broadcast.emit('new.message', message);//use this if everyone should be updated excpet the browser source of the message.
})
Here are the different ways you can emit:
io.sockets.on('connection', function(socket) {
//This message is only sent to the client corresponding to this socket.
socket.emit('private message', 'only you can see this');
//This message is sent to every single socket connected in this
//session, including this very socket.
io.sockets.emit('public message', 'everyone sees this');
//This message is sent to every single connected socket, except
//this very one (the one requesting the message to be broadcasted).
socket.broadcast.emit('exclude sender', 'one client wanted all of you to see this');
});
You can also add sockets to different rooms when they connect so that you only communicate messages with sockets from a given room:
io.sockets.on('connection', function(socket) {
//Add this socket to a room called 'room 1'.
socket.join('room 1');
//This message is received by every socket that has joined
//'room 1', including this one. (Note that a socket doesn't
//necessarily need to belong to a certain room to be able to
//request messages to be sent to that room).
io.to('room 1').emit('room message', 'everyone in room 1 sees this');
//This message is received by every socket that has joined
//'room 1', except this one.
socket.broadcast.to('room 1').emit('room message', 'everyone in room 1 sees this');
});

How to cleanly disconnect from a namespace in socket.io?

I have been trying to disconnect from a namespace or even from the main socket connection itself but have been failing. Below is my code
Server Side:
socket.on('userDisconnect', function () {
socket.disconnect();
console.log("User Disconnected");
});
Client Side:
// already connected to /world namespace
socket.emit('userDisconnect');
socket.disconnect();
socket = io.connect('http://something/india' );
I tried disconnecting from both client and serve side but it doesnt work. Can anyone point out the mistake.
This is what is been written to console by socket.io
info - booting client
debug - websocket writing 0::/world
User Disconnected
debug - client authorized for /india
debug - websocket writing 1::/india
/world is the namespace its trying to disconnect from and then its trying to connect to /india namespace.
This worked for me
broadcastSocket.packet({ type: 'disconnect' });
broadcastSocket.$emit('disconnect');
disconnectNamespace(broadcastSocket.name, broadcastSocket.socket);
function disconnectNamespace (name,socket) {
if (socket.namespaces[name]) {
var nsp = socket.of(name);
nsp.packet({ type: 'disconnect' });
nsp.$emit('disconnect');
delete socket.namespaces[name];
if (Object.keys(socket.namespaces).length === 0) {
socket.disconnect();
}
}
};
For socket.io v.1.3.2
Create with:
sio = io('ws://localhost:13000/device');
Delete with:
sio.disconnect();
delete sio.io.nsps[sio.nsp]; // sio.nsp = '/device'
delete sio;
This worked for me.
On the server
nsp.on('connection', (socket) => {
setTimeout(() => {
socket.disconnect(false)
}, 5000);
});
Disconnects this client. If the value of close is true, closes the underlying connection. Otherwise, it just disconnects the namespace. It's in the documentation https://socket.io/docs/server-api/
It doesn't look like you told the client to wait for disconnect before reconnecting.
// already connected to /world namespace
socket.emit('userDisconnect');
socket.on('disconnect', function () {
socket = io.connect('http://something/india');
// stuff with india socket
});
Use disconnect() method on the server or on the client (or both like your did in your example). When you first connect to the server, add 'forceNew':false to the client connect method, something like this:
var socket = io('http://localhost:3001', {'forceNew':false});

Node.js and Socket.IO - How to reconnect as soon as disconnect happens

I'm building a small prototype with node.js and socket.io. Everything is working well, the only issue I'm facing is that my node.js connection will disconnect and I'm forced to refresh the page in order to get the connection up and running again.
Is there a way to reestablish the connection as soon as the disconnect event is fired?
From what I've heard, this is a common issue. So, I'm looking for a best-practice approach to solving this problem :)
Thanks very much,
Dan
EDIT: socket.io now has built-in reconnection support. Use that.
e.g. (these are the defaults):
io.connect('http://localhost', {
'reconnection': true,
'reconnectionDelay': 500,
'reconnectionAttempts': 10
});
This is what I did:
socket.on('disconnect', function () {
console.log('reconnecting...')
socket.connect()
})
socket.on('connect_failed', function () {
console.log('connection failed. reconnecting...')
socket.connect()
})
It seems to work pretty well, though I've only tested it on the websocket transport.
edit: Socket.io has builtin-support now
When I used socket.io the disconnect did not happen(only when i closed the server manually). But you could just reconnect after say for example 10 seconds on failure or something on disconnect event.
socket.on('disconnect', function(){
// reconnect
});
I came up with the following implementation:
client-side javascript
var connected = false;
const RETRY_INTERVAL = 10000;
var timeout;
socket.on('connect', function() {
connected = true;
clearTimeout(timeout);
socket.send({'subscribe': 'schaftenaar'});
content.html("<b>Connected to server.</b>");
});
socket.on('disconnect', function() {
connected = false;
console.log('disconnected');
content.html("<b>Disconnected! Trying to automatically to reconnect in " +
RETRY_INTERVAL/1000 + " seconds.</b>");
retryConnectOnFailure(RETRY_INTERVAL);
});
var retryConnectOnFailure = function(retryInMilliseconds) {
setTimeout(function() {
if (!connected) {
$.get('/ping', function(data) {
connected = true;
window.location.href = unescape(window.location.pathname);
});
retryConnectOnFailure(retryInMilliseconds);
}
}, retryInMilliseconds);
}
// start connection
socket.connect();
retryConnectOnFailure(RETRY_INTERVAL);
serverside(node.js):
// express route to ping server.
app.get('/ping', function(req, res) {
res.send('pong');
});
Start reconnecting even if the first attempt fails
If the first connection attempt fails, socket.io 0.9.16 doesn't try to reconnect for some reason. This is how I worked around that.
//if this fails, socket.io gives up
var socket = io.connect();
//tell socket.io to never give up :)
socket.on('error', function(){
socket.socket.reconnect();
});
I know this has an accepted answer, but I searched forever to find what I was looking for and thought this may help out others.
If you want to let your client attempt to reconnect for infinity (I needed this for a project where few clients would be connected, but I needed them to always reconnect if I took the server down).
var max_socket_reconnects = 6;
var socket = io.connect('http://foo.bar',{
'max reconnection attempts' : max_socket_reconnects
});
socket.on("reconnecting", function(delay, attempt) {
if (attempt === max_socket_reconnects) {
setTimeout(function(){ socket.socket.reconnect(); }, 5000);
return console.log("Failed to reconnect. Lets try that again in 5 seconds.");
}
});

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