I'm using the Socket.io use function (https://socket.io/docs/server-api/#namespace-use-fn) to authenticate connections, but I'm not sure if I can disconnect a socket from within that function, because I don't know if the connection is made prior to calling 'use'.
Does Socket.io wait until the completion of io.use before making the connection? If the authentication fails, how can I stop the connection from being made?
My testing has shown that io.on('connection') is not fired until next() is called within the 'use' function. But I've also found that when I include socket.disconnect() inside of the 'use' function, the client will in fact disconnect, but the server still thinks the client is connected, as shown by io.clients.
I've read this SO question which cleared up some details about the 'use' function but didn't address my question: Socket.IO middleware, io.use
io.use(function (socket, next) {
let token = socket.handshake.query.token;
if (verify(token) == false) {
socket.disconnect(); // Can I do this here?
}
next();
});
// This isn't fired until the above 'use' function completes, but
// despite disconnecting above, 'on connection' still fires and `io.clients` shows the client is connected
io.on('connection', function (socket) {
setTimeout(function(){
// Get number of connected clients:
io.clients((error, clients) => {
if (error) throw error;
console.log(clients); // => [PZDoMHjiu8PYfRiKAAAF, Anw2LatarvGVVXEIAAAD]
});
}, 2000);
});
EDIT
I have mostly found the answer to this through testing. next() should only be called if the authentication succeeds. If it fails, just don't call next() and the socket will not connect. However, I do not understand why calling socket.disconnect() inside of the 'use' function creates a scenario where the server thinks it's connected to the client, but the client is actually disconnected.
Related
I have this scenario with socket.io:
I want to receive the data from a sever and Forward the data to webclient.But when I receive a lot of data and close the page, it console
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
DISCONNECTED FROM CLIENT
...(a lot)
Here is the code:
server:
var express=require('express');
var app=express();
var net=require('net');
var http=require('http').createServer(app);
var io=require('socket.io')(http);
var net=require('net');
var nodeServer = new net.Socket();
var aSocket=null;
io.on('connection', function (socketIO) {
aSocket=socketIO;
};
nodeServer.on('data', function(data) {
if(aSocket!=null){
aSocket.emit('pushToWebClient',useData);
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
}
client:
socket.on('pushToWebClient', function (useData) {
});
I find
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
console a lot of'DISCONNECTED FROM CLIENT' but actually it should console just once in the code.
I had even console.log(aSocket.id),it console just only one.
I don't know why it is console so many times.
I haved used setMaxListeners(10) to try to avoid it .
Will it lead to a memory leak？
It appears that you are registering multiple event listeners for the same disconnect event. In this code:
nodeServer.on('data', function(data) {
if(aSocket!=null){
aSocket.emit('pushToWebClient',useData);
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
}
You appear to be registering a new disconnect event listener every time you get a data message. So, if you have multiple listeners, then each one will get called when the socket disconnects and the result is that you will log the same message multiple times all for the same socket.
You can verify this is what is happening by moving your disconnect handler into the connection handler so it is only ever attached just once for each socket.
In addition putting asocket into a global or module-level variable means that your server code would only ever work with one single client at a time. It is not clear exactly what you are trying to do when you get data on the nodeserver connection - whether you're trying to send that data to only one specific client or to all connected clients.
I try to delete the code:
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
or moving it out of nodeServer handler,
it turn into normal and never suggest me to setMaxlisener.
I think maybe it is incorrect put one API into a API
And the envent maybe not release the socket,so it console multiple times .
EDIT: I'm moving this to the top because I saw that someone already provided my solution but you were having a problem managing the data sent to the client. Your aSocket variable will be overwritten by every new client that connects to your app. If you want to send data to a specific client using your server nodeServer, you should create a global variable (an array) that keeps track of all of your client socket connections. So instead of using one global variable aSocket do the following:
var net=require('net');
var nodeServer = new net.Socket();
var clients = [];
io.on('connection', function (socketIO) {
clients.push(socketIO);
var clientNum = clients.length-1;
aSocket.on('disconnect', function () {
clients.splice(clientNum, 1);
console.log('DISCONNECTED FROM CLIENT: '+socketIO.id);
});
};
nodeServer.on('data', function(data) {
//have your data object contain an identifier for the client that caused the handler to fire
//for the sake of the answer I just use data.id
var clientID = data.id;
if(clients[clientID]!=null){
clients[clientID].emit('pushToWebClient', useData);
}
}
Let me know how it goes! My original answer is below:
Try moving
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
out of your nodeServer.on('data', ...) event listener into the io.on('connection', ...) event listener like so:
io.on('connection', function (socketIO) {
aSocket=socketIO;
aSocket.on('disconnect', function () {
console.log('DISCONNECTED FROM CLIENT');
});
};
socket.io is designed to keep polling for the presence of the server/client. If either the server or the client are disconnected, the remaining 'side' continues to receive polling requests and, consequently, will continuously print an error.
You can see this effect on the client side in your browser when you disconnect your server and leave the client page open. If you look at the browser's error/console log what you should see is a continuous stream of net::ERR_CONNECTION_REFUSED errors. By placing the disconnect event handler in the .on('data', ...) handler for your server, you are seeing the converse of this situation.
net:ERR_CONNECTION_REFUSED example
This is basic code for socket.io
The following example attaches socket.io to a plain Node.JS HTTP
server listening on port 3000.
var server = require('http').createServer();
var io = require('socket.io')(server);
io.on('connection', function(client){
client.on('event', function(data){});
client.on('disconnect', function(){});
});
server.listen(3000);
I think, you should try.
Am not able to call socket-client listener using sails.sockets.js onConnect event on server side..
E.g
onConnect: function(session, socket) {
socket.on('chat message', function(msg){
console.log(msg);
console.log("socket.id: " + socket.id);
sails.sockets.broadcast(socket.id, 'chat message', {msg:msg});
});
}
Please let me know whats the correct way of calling back to your socket-client using socket-server events like onConnect..
If you are using standard sails.js socket library:
$(document).ready(function() {
io.socket.on('connect', function() {
});
io.socket.on('chat message', function(data) {
io.socket.post('/routeToAction', {
}, function(data, jwres) {
});
});
});
for newer version, you have to use config/bootstrap.js file for listen events
module.exports.bootstrap = function(cb) {
// handle connect socket first event executes after logged in
sails.io.on('connect', function (socket){
// store facebook token here
});
// handle custom listener for other stuff
sails.io.on('doSomeStuff', function (socket){
// check facebook token match with requested token
});
cb();
};
client : you can simple emit "doSomeStuff" after logged in with facebook and pass token with each request
Finally am become little expert in web sockets who knows back anf forth of push technoligy via websockets..
How to start with websockets :
Step 1: Choose any websocket framework for your application and install socket client on client side and socker server on server side with listeners(imp.).
Step 2: Once you are ready with socket setup on both sides then your client/browser will make a connection after every page load which is listened on server side via onConnect listener or event.
Step 3: Successfull connection on both sides giving you socket object which contains each client socket id which is managed at server side to either join any channel/room or just to make a broadcast or blast.
Remember:
i. Socket object is responsible for defining listeners on both client side and server side. Using socket object you can pass any data to listeners.
ii. Socket connection is very helpful when you trying to push data from client to server and vice-versa.
iii. You can make your small chatter tool with it once you understand as mentioned above.
Will share similar working snippet soon..
//onConnect event on server side
onConnect: function(session, socket) {
console.log("Socket Connect Successfully: " + socket.id );
socket.on('chatAgency', function(data){
sails.sockets.broadcast(data.agencyId,"chatAgency", {message:data.message,agencyId:session.agencyId});
});
},
Whenever I disconnect using socket.disconnect(); and then reconnect using socket.connect();, the server runs my handshake code twice. The strange thing is, even though the server connection code runs twice, there is only one connection in my array after reconnecting. This happens on an accidental disconnection, intentional, or even if the server restarts. Bit of code:
io.on('connection', OnConnect);
function OnConnect(socket) {
var connection = { socket: socket, realIp: ip, token: GenerateConnToken() };
connections.push(connection);
console.log('Connected');
// Client will respond to this by emitting "client-send-info".
// This is emitted once on initial connect, but twice on reconnect.
socket.emit('acknowledge', connection.token);
socket.on('client-send-info', function() {
console.log('Client Sent Info');
});
socket.on('disconnect', function() {
console.log('Disconnected');
});
}
The above code, when a client connects, disconnects, and then reconnects once, will produce the following log:
Connected
Client Sent Info
Disconnected
Connected
Client Sent Info
Client Sent Info
Why is it that, when reconnecting, the connection code will run twice, but only create one connection object?
EDIT: Upon further inspection, it seems that a different piece of my connection code is being performed twice when the client reconnects. The above code is updated to reflect the relevant information.
Strangely, the solution is completely client side. Instead of the following code:
var socket = io.connect();
socket.on('connect' function() {
socket.on('acknowledge', function() {
});
});
You have to use:
var socket = io.connect();
socket.on('connect' function() {
});
socket.on('acknowledge', function() {
});
Otherwise, the server will appear to be sending multiple emits when it is in reality only sending one, and it's the client that falsely receives multiples. With the second code format, the client successfully connects initially, disconnects, and reconnects without receiving multiple emits.
Simply, don't put any additional socket.on('x') calls inside the on('connection') call. Leave them all outside it.
Looking at the example given at the nodejs domain doc page: http://nodejs.org/api/domain.html, the recommended way to restart a worker using cluster is to call first disconnect in the worker part, and listen to the disconnect event in the master part. However, if you just copy/paste the example given, you will notice that the disconnect() call does not shutdown the current worker:
What happens here is:
try {
var killtimer = setTimeout(function() {
process.exit(1);
}, 30000);
killtimer.unref();
server.close();
cluster.worker.disconnect();
res.statusCode = 500;
res.setHeader('content-type', 'text/plain');
res.end('Oops, there was a problem!\n');
} catch (er2) {
console.error('Error sending 500!', er2.stack);
}
I do a get request at /error
A timer is started: in 30s the process will be killed if not already
The http server is shut down
The worker is disconnected (but still alive)
The 500 page is displayed
I do a second get request at error (before 30s)
New timer started
Server is already closed => throw an error
The error is catched in the "catch" block and no result is sent back to the client, so on the client side, the page is waiting without any message.
In my opinion, it would be better to just kill the worker, and listen to the 'exit' event on the master part to fork again. This way, the 500 error is always sent during an error:
try {
var killtimer = setTimeout(function() {
process.exit(1);
}, 30000);
killtimer.unref();
server.close();
res.statusCode = 500;
res.setHeader('content-type', 'text/plain');
res.end('Oops, there was a problem!\n');
cluster.worker.kill();
} catch (er2) {
console.error('Error sending 500!', er2);
}
I'm not sure about the down side effects using kill instead of disconnect, but it seems disconnect is waiting the server to close, however it seems this is not working (at least not like it should)
I just would like some feedbacks about this. There could be a good reason this example is written this way that I've missed.
Thanks
EDIT:
I've just checked with curl, and it works well.
However I was previously testing with Chrome, and it seems that after sending back the 500 response, chrome does a second request BEFORE the server actually ends to close.
In this case, the server is closing and not closed (which means the worker is also disconnecting without being disconnected), causing the second request to be handled by the same worker as before so:
It prevents the server to finish to close
The second server.close(); line being evaluated, it triggers an exception because the server is not closed.
All following requests will trigger the same exception until the killtimer callback is called.
I figured it out, actually when the server is closing and receives a request at the same time, it stops its closing process.
So he still accepts connection, but cannot be closed anymore.
Even without cluster, this simple example illustrates this:
var PORT = 8080;
var domain = require('domain');
var server = require('http').createServer(function(req, res) {
var d = domain.create();
d.on('error', function(er) {
try {
var killtimer = setTimeout(function() {
process.exit(1);
}, 30000);
killtimer.unref();
console.log('Trying to close the server');
server.close(function() {
console.log('server is closed!');
});
console.log('The server should not now accepts new requests, it should be in "closing state"');
res.statusCode = 500;
res.setHeader('content-type', 'text/plain');
res.end('Oops, there was a problem!\n');
} catch (er2) {
console.error('Error sending 500!', er2);
}
});
d.add(req);
d.add(res);
d.run(function() {
console.log('New request at: %s', req.url);
// error
setTimeout(function() {
flerb.bark();
});
});
});
server.listen(PORT);
Just run:
curl http://127.0.0.1:8080/ http://127.0.0.1:8080/
Output:
New request at: /
Trying to close the server
The server should not now accepts new requests, it should be in "closing state"
New request at: /
Trying to close the server
Error sending 500! [Error: Not running]
Now single request:
curl http://127.0.0.1:8080/
Output:
New request at: /
Trying to close the server
The server should not now accepts new requests, it should be in "closing state"
server is closed!
So with chrome doing 1 more request for the favicon for example, the server is not able to shutdown.
For now I'll keep using worker.kill() which makes the worker not to wait for the server to stops.
I ran into the same problem around 6 months ago, sadly don't have any code to demonstrate as it was from my previous job. I solved it by explicitly sending a message to the worker and calling disconnect at the same time. Disconnect prevents the worker from taking on new work and in my case as i was tracking all work that the worker was doing (it was for an upload service that had long running uploads) i was able to wait until all of them are finished and then exit with 0.
Is it possible for client to send a socket data when it gets
disconnected (user closes the browser, or tab)?
Because, I found that default bind on disconnect doesn't take any input data.
//on server side
socket.on('disconnect',function(){
//in other binds, it takes 'data' as an input but this does not
});
I tried to resolve this problem by using the jQuery's unload method
like below
//on client side
$(window).unload(function(){
socket.emit('depart','I am leaving');
});
However, it does not seem to emit at all on unload. (maybe socket gets out of scope on unload?)
Is there a way to send data through websocket to the server when client disconnects?
Secondly, Is there any way that I can store a string data in socket? For instance,
socket.userName = userNameVar;
--update--
Here is how I set up environment on the serverside
io.sockets.on('connection',function(socket){
socket.on('depart',function(data){
console.log(data);
console.log("user left");
});
socket.on('disconnect',function(){
console.log("user disconnected");
});
});
and following code is in the client side.
var socket = io.connect(hostVar);
$(window).unload(function(){
socket.emit('depart','I am leaving');
});
The reason you cannot send data on disconnect is because you are disconnected. What you are asking is somewhat akin to saying "Can i still talk to the person on the phone after they've hung up on me?"
If you want to emit the 'depart' event, then you still have to capture it inside your 'connect' handler on server side:
As in:
io.socket.on('connection', function(socket) {
socket.on('depart', function(msg) {
// you should get depart message here
});
})
Your depart event will come BEFORE the connection is terminated. disconnect is only raised by server upon a successful disconnection and therefore it cannot receive any messages.
Give it a try and tell me if this works :)
Use this instead
$(window).on('beforeunload',()=>{
socket.emit('page_unload');
});
and on server side
io.socket.on('connection', function(socket) {
socket.on('page_unload', function(msg) {
// client has reloaded page or closed page
});
})