I think there may be an issue with the Nodejs v5.3.0 NET api. I am wanting to rely on the socket.remoteAddress field flipping to undefined when the socket is destroyed.
socket.remoteAddress
The string representation of the remote IP address. For example, '74.125.127.100' or '2001:4860:a005::68'. Value may be undefined if the socket is destroyed (for example, if the client disconnected).
The challenge here is the may language above (bold added for emphasis).
Context: I'm writing a MEaN app that uses sockets to communicate with a remote deviec. The connection is often disconnected and I need to seamlessly reconnect it before use. I have the various functions needed to transmit call connect() before they want to transmit to ensure the connection is live.
UPDATED WITH FIX per mscdex:
if ( !client.readable )
client.connect(PORT,HOST);
else
logger.debug('Attempt to reconnect on an active connection. Ignored.');
client.readable provides immediate status on the network connection even if the intent is to write to the connection. client.writable is buffered and thus 'lies' (is overly optimistic) about the connection being present or able to be established.
The below is working code:
var logger = require('winston');
var net = require('net');
var client = new net.Socket();
var init = function() {
logger.info('Calling connect now...' );
connect();
};
exports.init = init;
var output = function(action, id) {
connect();
//Transmit stuff here
};
exports.output = output;
var connect = function() {
// Check to see if remoteAddress is undefined. If so, then connect
logger.debug('Test if connection is active: ' + client.remoteAddress);
if ( typeof (client.remoteAddress) == 'undefined' ) {
client.connect( 2101, '10.10.10.4', function() {
logger.info('Connection now open');
});
}
else {
logger.debug('Attempting reconnect on active connection. Ignore: ' + client.remoteAddress);
}
};
// This events, as expected, when the VPN is connected and data is received.
client.on('data', function() {
logger.debug('Data incoming');
});
// This events, as expected, when the VPN drops
client.on('error', function() {
logger.debug('Connection error so destroy() the client');
client.destroy();
// I *was* expecting destroy() to make typeof (client.remoteAddress) = 'undefined'. It does not.
});
Here's what the resultant log looks like
info: Calling connect now...
debug: Test if connection is active: undefined
info: Connection now open
debug: Data incoming
debug: Data incoming
debug: Test if connection is active: 10.10.10.4
debug: Attempting reconnect on active connection. Ignore: 10.10.10.4
POST /elk/output 200 18.122 ms - 2
debug: Data incoming
I disconnected the VPN
debug: Test if connection is active: 10.10.10.4
debug: Attempting reconnect on active connection. Ignore: 10.10.10.4
POST /elk/output 200 1.546 ms - 2
debug: Connection error so destroy() the client
Now, given the client.destroy(); call, I'd expect client.remoteAddress to become undefined per document but it is not.
debug: Test if connection is active: 10.10.10.4
debug: Attempting reconnect on active connection. Ignore: 10.10.10.4
debug: Connection error so destroy() the client
POST /elk/output 200 1.063 ms - 2
Thoughts?
Thanks
Don't use remote ip to detect if the remote connection has been disconnected. Instead, subscribe to the close event (and depending on the use case, maybe the end event as well):
client.on('close',function(){
// client has been disconnected.
connect();
});
client.on('end',function(){
// client wants to disconnect.
connect();
});
To really close the socket you can set the close (and end) handlers to do nothing:
client.on('close',function(){});
client.destroy();
You could also check if the TCP stream is readable or not by checking client.readable.
Related
Hello community,
Since the morning I am faced with an idea not to say a problem I want to store clients (sockets) in order to re-invoke them later, I know that it is not too clear I will explain in detail:
First I have a server interface (ServerSocket) net.Server() which will receive clients (sockets) net.Socket() and this one will be stored in a Map() with a unique ID for each client, and each time I want to communicate with one of them I call map.get(id).write ... or other function,
Everything works fine until I close the server, automatically the sockets will be killed ... saying that I have found a solution to store the clients for my case (vuex) or localStorage to simplify what I want is when I restart the server and I invoke one of the client it will always be active.
So my main questions:
How can I keep clients still active after the server is closed?
How can I Store sockets and check if they are active after restarting server?
var net = require("net");
var server = new net.Server();
var sockets = new Map();
/**
* This events is called when server is successfully listened.
*/
server.on("listening", () => {
console.log("Server Listen in port 4444");
});
/**
* This events is called when error occur in server
*/
server.on("error", (e) => {
if (e.code === "EADDRINUSE") {
console.log("Address in use, retrying...");
}
});
/**
* This events is called when a new client is connected to server.
*/
server.on("connection", (socket) => {
var alreadyExist = false;
sockets.forEach((soc) => {
if (soc.remoteAddress === socket.remoteAddress) {
alreadyExist = true;
}
});
if (alreadyExist) {
socket.end();
} else {
socket.setKeepAlive(true, Infinity);
socket.setDefaultEncoding("utf8");
socket.id = nanoid(10);
sockets.set(socket.id, socket);
socket.on("error", (e) => {
console.log(e);
if (e.code === "ECONNRESET") {
console.log("Socket end shell with CTRL+C");
console.log("DEL[ERROR]: " + socket.id);
}
});
socket.on("close", () => {
console.log("DEL[CLOSE]: " + socket.id);
});
socket.on("end", () => {
console.log("DEL[END]: " + socket.id);
});
socket.on("timeout", () => {
console.log("timeout !");
});
var child = sockets.get(res.id);
child.write(/* HERE I SEND COMMAND NOT IMPORTANT ! */);
socket.on("data", (data) => {
console.log("Received data from socket " + data);
});
}
});
How can I keep clients still active after the server is closed?
A client can't maintain a connection to a server that is not running. The client is free to do whatever it wants on its own when the server shuts down, but it cannot maintain a connection to that server that is down. The whole definition of a "connection" is between two live endpoints.
How can I Store sockets and check if they are active after restarting server?
You can't store sockets when the server goes down. A socket is an OS representation of a live connection, TCP state, etc... When the server goes down and then restarts, that previous socket is gone. If it wasn't closed by the server before it shut-down, then it was cleaned up by the OS when the server process closed. It's gone.
I would make a suggestion that you're asking for the wrong thing here. Sockets don't outlive their process and don't stay alive when one end of the connection goes down.
Instead, the usual architecture for this is automatic reconnection. When the client gets notified that the server is no longer there, the client attempts to reconnect on some time interval. When, at some future time, the server starts up again, the client can then connect back to it and re-establish the connection.
If part of your connection initiation is an exchange of some sort of clientID, then a client can reconnect, present it's identifier and the server can know exactly which client it is and things can then continue as before with a new socket connection, but everything else proceeding as if the previous socket connection shut-down never happened. You just rebuild your Map object on the server as the clients reconnect.
For scalability reasons, your clients would generally implement some sort of back-off (often with some random jitter added) so that when your server comes back online, it doesn't get immediately hammered by hundreds of clients all trying to connect at the exact same moment.
I have a socket running in nodejs and using this socket in html page this is working fine and some times I'm receiving the error on developer console as like
failed: Connection closed before receiving a handshake response. In this time my update not getting reflect on the user screen. Actually whenever the changes updated in admin screen I written the login in laravel to store this values into the redis and I have used the laravel event broadcast and in node js socket.io read the redis value change and push the values into the user screens.
I have code in laravel as like,
Laravel Controller,
public function updatecommoditygroup(Request $request)
{
$request_data = array();
parse_str($request, $request_data);
app('redis')->set("ssahaitrdcommoditydata", json_encode($request_data['commodity']));
event(new SSAHAITRDCommodityUpdates($request_data['commodity']));
}
In this above controller when the api call receives just store the values into this redis key and broadcast the event.
In my event class,
public $updatedata;
public function __construct($updatedata)
{
$this->updatedata = $updatedata;
}
public function broadcastOn()
{
return ['ssahaitrdupdatecommodity'];
}
Finally I have written my socket.io file as like below,
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var Redis = require('ioredis');
var redis = new Redis({ port: 6379 } );
redis.subscribe('ssahaitrdupdatecommodity', function(err, count) {
});
io.on('connection', function(socket) {
console.log('A client connected');
});
redis.on('pmessage', function(subscribed, channel, data) {
data = JSON.parse(data);
io.emit(channel + ':' + data.event, data.data);
});
redis.on('message', function(channel, message) {
message = JSON.parse(message);
io.emit(channel + ':' + message.event, message.data);
});
http.listen(3001, function(){
console.log('Listening on Port 3001');
});
When I have update the data from admin I'm passing to laravel controller, and controller will store the received data into redis database and pass to event broadcast.And event broadcast pass the values to socket server and socket server push the data whenever the redis key get change to client page.
In client page I have written the code as like below,
<script src="../assets/js/socket.io.js"></script>
var socket = io('http://ip:3001/');
socket.on("novnathupdatecommodity:App\\Events\\NOVNATHCommodityUpdates", function(data){
//received data processing in client
});
Everything working fine in most of the time and some times issue facing like
**VM35846 socket.io.js:7 WebSocket connection to 'ws://host:3001/socket.io/?EIO=3&transport=websocket&sid=p8EsriJGGCemaon3ASuh' failed: Connection closed before receiving a handshake response**
By this issue user page not getting update with new data. Could you please anyone help me to solve this issue and give the best solution for this issue.
I think this is because your socket connection timeout.
new io({
path:,
serveClient:,
orgins:,
pingTimeout:,
pingInterval:
});
The above is the socket configuration. If you are not configuring socket sometime it behaves strangely. I do not know the core reason, but i too have faced similar issues that implementing the socket configuration solved it.
Socket.io Server
Similar configuration should be done on the client side. There is an option of timeout in client side
Socket.io Client
For example.
Say this is your front-end code
You connect to the socket server using the following command:
io('http://ip:3001', { path: '/demo/socket' });
In your server side when creating the connection:
const io = require("socket.io");
const socket = new io({
path: "/demo/socket",
serveClient: false /*whether to serve the client files (true/false)*/,
orgins: "*" /*Supports cross orgine i.e) it helps to work in different browser*/,
pingTimeout: 6000 /*how many ms the connection needs to be opened before we receive a ping from client i.e) If the client/ front end doesnt send a ping to the server for x amount of ms the connection will be closed in the server end for that specific client*/,
pingInterval: 6000 /* how many ms before sending a new ping packet */
});
socket.listen(http);
Note:
To avoid complication start you http server first and then start you sockets.
There are other options available, but the above are the most common ones.
I am just describing what i see in the socket.io document available in github.socket_config. Hope this helps
I am working on Socket IO, the connection between the client and the server is established successfully. I am facing two problems:
1 - When the initial connection is made between the client and the server, the socket.client.id on server and socket.id on client side, both are the same, but when I refresh the client page, the id of the client changes to other one, but on the server it is still the same. Does it makes any issue / problem while communicating with the server or even with the client using sockets, while not having the same ids ? or does the id on the server get changed when the client page is refreshed ?
2 - On the initial connection establishment the socket passes a messages, using socket.emit() from server and receives as socket.on() on client. But when I try to emit anything from client it doesn't get received on server.
Socket Connections
function Globals() {
this.socketConnection = async function() {
let p = new Promise(function(res, rej) {
io.on("connection", function(socket) {
if (socket.connected) {
res(socket);
} else {
rej("Socket Connection Error !");
}
})
})
return await p;
}
}
new Globals().socketConnection().then(function(soc) {
console.log(soc.client.id);
socket = soc;
soc.emit("Hi");
soc.on("Nady", function() {
console.log("I am called");
})
})
Client Side Connection
function Globals() {
this.socketConnection = async function() {
var socket = io('http://localhost:8080');
let p = new Promise(function(res, rej) {
socket.on('connect', function() {
if (socket.connected) {
console.log(socket.id);
res(socket);
}
})
})
return await p;
}
}
var socket;
new App().socketConnection().then(function(s) {
socket = s;
});
function ScrapJobs() {
var socket;
new App().socketConnection().then(function(s) {
socket = s;
});
var _this = this;
this.attachListeners = function() {
qs("#init-scrap").ev("click", _this.startScrapping);
}
this.startScrapping = function() {
console.log("I am cliced");
socket.on("Hi", function() {
console.log("Hi Nadeem");
})
socket.emit("Nady");
}
}
When the initial connection is made between the client and the server, the socket.client.id on server and socket.id on client side, both are the same, but when I refresh the client page, the id of the client changes to other one, but on the server it is still the same. Does it makes any issue
The client side socket.id value is set on the client socket object after the connect event is received and is updated (e.g. modified) upon a reconnect event.
It appears that the socket.io infrastructure will keep them the same on client and server. If the client disconnects and then reconnects, there will be a new connection with a new id on both client and server. It is possible you are attempting to hang onto the old socket object on the server after the client has disconnected it (we can't really see enough of your server code to evaluate that).
On the initial connection establishment the socket passes a messages, using socket.emit() from server and receives as socket.on() on client. But when I try to emit anything from client it doesn't get received on server.
You'd have to show us a reproducible case. This does not happen if you are coding things correctly. I would guess that you do not have the right listeners for messages on the right socket in order to see the messages you are sending. I promise you that sending a message from client to server works just fine when implemented properly.
A general comment about your code. Both code blocks you show appear to be stuffing a socket object into a higher scoped (or perhaps even global) variable. That is likely part the cause of your problem because that socket object can become dead if the client reconnects for any reason. Plus putting any sort of socket object into a global or module level variable makes your server only capable of serving one client - it's simply not how you design multi-client servers.
I'm having a socket.io app that basically receives signals from a frontend in order to kill and start a new ffmpeg process (based on .spawn()).
Everything works like expected, but often I get a 525 error from cloudflare. The error message is: Cloudflare is unable to establish an SSL connection to the origin server.
It works like 9 out of 10 times.I noticed that more of these errors pop up whenever a kill + spawn is done. Could it be the case that something block the event loop and because of this blocks all incoming requests and cloudflare logs these as a handshake failed error?
Contacting cloudflare support gives me back this info (this is the request they do to my server):
Time id host message upstream
2017-08-16T09:14:24.000Z 38f34880faf04433 xxxxxx.com:2096 peer closed connection in SSL handshake while SSL handshaking to upstream https://xxx.xxx.xxx.xxx:2096/socket.io/?EIO=3&transport=polling&t=LtgKens
I'm debugging for some time now, but can't seem to find a solutions myself.
This is how I initialize my socketIO server.
/**
* Start the socket server
*/
var startSocketIO = function() {
var ssl_options = {
key: fs.readFileSync(sslConfig.keyFile, 'utf8'),
cert: fs.readFileSync(sslConfig.certificateFile, 'utf8')
};
self.app = require('https').createServer(ssl_options, express);
self.io = require('socket.io')(self.app);
self.io.set('transports', ['websocket', 'polling']);
self.app.listen(2096, function() {
console.log('Socket.IO Started on port 2096');
});
};
This is the listener code on the server side
this.io.on('connection', function (socket) {
console.log('new connection');
/**
* Connection to the room
*/
socket.on('changeVideo', function (data) {
//Send to start.js and start.js will kill the ffmpeg process and
start a new one
socket.emit('changeVideo');
});
});
Another thing that I observer while debugging (I only got this a few times):
The text new connection displayed on the server and the connected client emits the changevideo event but nothing happens on the server side instead the client just
keeps reconnecting.
This is a simplified version of the nodejs code. If you have more questions, just let me know.
Thanks!
Im having trouble to send the client costum userid to the node.js
For some reason it wont send the userid to the server to submit it. there is no output for it from the node log.
client sided:
var socket = io.connect('http://sitename.eu:1337/');
var user_id = <?echo $data->userid?>;
socket.on('connection',function(user_id) {
socket.emit('setuserid', user_id);
});
server sided:
io.on('connection', function (socket){ // just to prove that the code is inside it
logger.info('SocketIO > Connected socket ' + socket.id);
socket.on('setuserid', function (userId) {
users[userId]=socket;
socket.userid = userId;
logger.info("setting userid...");
});
only output:
2015-07-12T21:09:05.656Z - info: SocketIO > Connected socket E2ghiXGfTJWtgWs4AAAA
2015-07-12T21:09:08.134Z - info: SocketIO > Connected socket XY0c-A_ZveEUs_CuAAAB
2015-07-12T21:09:21.393Z - info: SocketIO > Disconnected socket E2ghiXGfTJWtgWs4AAAA
2015-07-12T21:09:22.610Z - info: SocketIO > Connected socket G3DmRKSymCuaximOAAAC
Change this line:
socket.on('connection',function(user_id) {
into:
socket.on('connect',function() {
Socket.io triggers an event called connect (http://socket.io/docs/client-api/#io#emitter). Since connection is never called, that function never gets run.
In addition, make sure you remove the user_id as a parameter.
Otherwise, you overwrite the global scope and will be sending undefined as a result for userid