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Unable to close tcp socket on event error at node server when client is not gracefully disconnects

I have writen a simple javascript chat application using tcp socket on node.js.
It works fine on local server (Ubuntu 16.04, Node version 8.7), but when deployed at live server (Debian OS, Node version 8.7), application is not working properly.
Problem is that when client's internet disconnects abruptly, or application is crushed, node server does not enter event-error, to remove the client from lobby. If client ends the socket connection gracefully, server calls event-end, event-disconnect, or event-close to remove the socket from lobby and close the socket as well.
NOTE: No issue is faced when same code runs on local server. On local server, when disconnection is abrupt, code enters in "error" event and removes the client from lobby list.
Kindly, help me out, as I might be missing some thing.
var tls = require('tls');
var fs = require('fs');
net = require('net');
var options = {
key : fs.readFileSync('/root/server.key'),
cert : fs.readFileSync('/root/server.cert')
};
// Keep track of devices
var clients = [];
var ip = [,];
var server = tls.createServer(options, function (socket) {
// Identify device
socket.name = socket.remoteAddress + ":" + socket.remotePort
socket.on('uncaughtException', function(er) {
console.error(er.stack);
socket.exit(1);
});
// Remove device from the list when connection dropped
socket.on('error', function(error_inappropriate) {
console.log('Device_Left: ', socket.name);
clients.splice(clients.indexOf(socket), 1);
console.log('Warning:', " " + socket.name + " inappropriate_con_closed. " + error_inappropriate.message);
});
socket.on('close', function() {
console.log('Event:', 'CLOSE event triggered, connection closed');
clients.splice(clients.indexOf(socket), 1);
});
socket.on('disconnect', function() {
console.log('Warning:', 'DISCONNECT event triggered, device disconnected');
clients.splice(clients.indexOf(socket), 1);
});
socket.on('end', function () {
clients.splice(clients.indexOf(socket), 1);
broadcast(socket.name + " left the chat.\n");
});
// Handle incoming messages from devices
socket.on('data', function (data) {
broadcast(socket.name + "says: " + data);
});
// Send a message to all devices
function broadcast(message, sender) {
clients.forEach(function (client) {
// Don't want to send it to sender
if (client === sender) return;
client.write(message);
});
}
}).listen(443);

data received from c# to localhost is not shown in localhost webpage - nodemon app crashed

I'm trying to pass data from c# using console application to webpage using socket.io in real time
here is my c# code:
static void Main(string[] args)
{
int i = 0;
while(true)
{
//String data = Console.ReadLine();
String data = i.ToString();
if(data.Equals("exit", StringComparison.OrdinalIgnoreCase)) break; //If the user types "exit" then quit the program
SendData("127.0.0.1", 41181, data); //Send data to that host address, on that port, with this 'data' to be sent
//Note the 41181 port is the same as the one we used in server.bind() in the Javascript file.
System.Threading.Thread.Sleep(50); //Sleep for 50ms
i++;
}
}
public static void SendData(string host, int destPort, string data)
{
IPAddress dest = Dns.GetHostAddresses(host)[0]; //Get the destination IP Address
IPEndPoint ePoint = new IPEndPoint(dest, destPort);
byte[] outBuffer = Encoding.ASCII.GetBytes(data); //Convert the data to a byte array
Socket mySocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); //Create a socket using the same protocols as in the Javascript file (Dgram and Udp)
mySocket.SendTo(outBuffer, ePoint); //Send the data to the socket
mySocket.Close(); //Socket use over, time to close it
}
this is app.js
var app = require('http').createServer(handler);
var io = require('socket.io').listen(app);
var fs = require('fs');
var mySocket = 0;
app.listen(3000); //Which port are we going to listen to?
function handler (req, res) {
fs.readFile(__dirname + '/index.html', //Load and display outputs to the index.html file
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.on('connection', function (socket) {
console.log('Webpage connected'); //Confirmation that the socket has connection to the webpage
mySocket = socket;
});
//UDP server on 41181
var dgram = require("dgram");
var server = dgram.createSocket("udp4");
server.on("message", function (msg, rinfo) {
console.log("Broadcasting Message: " + msg); //Display the message coming from the terminal to the command line for debugging
if (mySocket != 0) {
mySocket.emit('field', "" + msg);
mySocket.broadcast.emit('field', "" + msg); //Display the message from the terminal to the webpage
}
});
server.on("listening", function () {
var address = server.address(); //IPAddress of the server
console.log("UDP server listening to " + address.address + ":" + address.port);
});
server.bind(41181);
finally this is index.html
<html>
<head>
<script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>
</head>
<body>
<script>
var socket = io();
socket.on('field', function (data) {
$("#field").html(data);
});
</script>
Data from C#: <div id="field"></div>
</body>
</html>
I used this article to implement it, everything, seems work fine for example when I send data to console of node.js it display it but as soon as I run the page (localhost:3000) after several printing "webpage connected" it shows this error in my console:
nodemon app crashed - waiting for file changes
can someone give me a solution?
this my result picture

Error may occure on a different levels. I see that you are not listenning socket errors, both for server and io.
Both of them are based on EventEmiter approach, so both have error event to listen.
Try to listen all possible error places, this will give you additional infromation on why your app crashed.
server.on("error", err => console.error("server error occured", err));
io.on("error", err => console.error("io error occured", err));
Update
Replace in index.html script loading for socket.io with this.
<script src="/socket.io/socket.io.js"></script>.
Then, all re-connection issues should gone. I'm not pretty sure how it is working.

Connecting Client Server in ASP.net MVC Signal R

This is my Signal R Client.
I get this error when i run my client.(0x800a139e - JavaScript runtime error: SignalR: Error loading hubs. Ensure your hubs reference is correct, e.g. .)
The exception comes from line $.connection.hub.start
There is a ServerHub class in a folder HUBS in my Server application which runs fine.
Can anyone help me out..
Thanks
<script src="~/Scripts/jquery.signalR-2.2.0.min.js"></script>
<script src="http://localhost:39670/MySignalRServer/signalr/hubs"></script>
var ChatHubProxy = $.hubConnection("http://localhost:39670/MySignalRServer/signalr/hubs");
var chat = ChatHubProxy.createHubProxy('ServerHub');
chat.on("addNewMessageToPage",function (name, message) {
// Add the message to the page.
$('#discussion').append('<li><strong>' + htmlEncode(name)
+ '</strong>: ' + htmlEncode(message) + '</li>');
});
$.connection.hub.start({jsonp:true}).done(function () {
$('#sendmessage').click(function () {
// Call the Send method on the hub.
chat.server.send($('#displayname').val(), $('#message').val());
alert("hiii");
// Clear text box and reset focus for next comment.
$('#message').val('').focus();
});
});

Try change your code to :
<script src="~/Scripts/jquery.signalR-2.2.0.min.js"></script>
<script src="http://localhost:39670/MySignalRServer/signalr/hubs"></script>
var chat = $.connection.ServerHub; //here
chat.on("addNewMessageToPage", function(name, message) {
// Add the message to the page.
$('#discussion').append('<li><strong>' + htmlEncode(name)
+ '</strong>: ' + htmlEncode(message) + '</li>');
});
$.connection.hub.start().done(function() { //here
$('#sendmessage').click(function() {
// Call the Send method on the hub.
chat.server.send($('#displayname').val(), $('#message').val());
alert("hiii");
// Clear text box and reset focus for next comment.
$('#message').val('').focus();
});
});
And make sure that this address is good - <script src="http://localhost:39670/MySignalRServer/signalr/hubs"></script>
I always use this - <script src="/signalr/hubs"></script>
And add HubName Attribute
[HubName("ServerHub")]
public class ServerHub : Hub
{
public string Send(string name, string message)
{
Clients.All.broadcastMessage(name, message);
return null;
}
}
or change this code :
var chat = $.connection.ServerHub;
to
var chat = $.connection.serverHub;
Demo project : https://github.com/czerwonkabartosz/SignalRDemo

How to save incoming textfile from client from websocket connection

I'm trying to implement a websocket server in node.js without using any framework.
Sending messages from client to server is working fine. But now I tried to send a text file from client to server. I can see the content on the server side by using console.log in the terminal.
But:
how can i get the file information ? (name, created/edited date, etc. ?)
how can i save the file ?
Client code:
(function () {
'use strict';
var output, ws;
//Display logging information in the document
function log(s) {
var p = document.createElement("p");
p.style.wordWrap = "break-word";
p.textContent = s;
output.appendChild(p);
//Also log information on the javascript console
window.console.log(s);
}
//Send a message on the Websocket
function sendMessage(msg) {
console.log(ws.binaryType);
ws.send(msg);
console.log("Message sent");
}
//Initialize WebSocket connection and event handlers
function setup() {
output = document.getElementById("output");
ws = new window.WebSocket("ws://localhost:9999/");
//Listen for the connection open event then call the sendMessage function
ws.onopen = function () {
console.log("Connected");
document.getElementById('fl').onchange = function() {
sendMessage(document.querySelector('input[type="file"]').files[0]);
};
sendMessage("Hello Galileo!");
}
//Listen for the close connection event
ws.onclose = function (e) {
if(this.readyState == 2){
console.log('Connection is closing (Closing Handshake).')
}
else if(this.readyState == 3){
console.log('Connection closed. Has been closed or could not be opened.')
}
else{
console.log('Unhandled ReadyState: ',this.readyState);
}
console.log("Disconnected: " +
' reason:' + e.reason +
' was clean:' + e.wasClean +
' code:' + e.code);
}
//Listen for connection errors
ws.onerror = function (e) {
console.log("Error: " + e);
}
//Listen for new messages arriving at the client
ws.onmessage = function (e) {
console.log("Message received: " + e.data);
//Close the socket once one message has arrived
ws.close();
}
}
//Start running the example
setup();
})();
HTML Code
<!DOCTYPE html>
<html>
<head>
<title>Websocket Echo Client</title>
<meta charset="utf-8"/>
</head>
<body>
<h2>Websocket Echo Client</h2>
<div id="output"></div>
<input type="file" id="fl"/>
<script src="websocket.js"></script>
</body>
</html>
Server code
switch (opcode) {
case opcodes.TEXT:
this.payload = payload.toString("utf8");
winston.log('info','Text:\r\n', this.payload);
break;
case opcodes.BINARY:
console.log('info','File:\r\n', payload.toString("utf8"));

As far as I know the payload you're receiving on the server side does not contain the meta data about the file. I believe the File object is treated as a normal Blob with some extra meta data and the ws.send is only handling it like a Blob (it has no special handling for File).
The meta data can be accessed using
document.querySelector('input[type="file"]').files[0].name
document.querySelector('input[type="file"]').files[0].size
document.querySelector('input[type="file"]').files[0].type
And then send separately.

include socket.io server into my html

I have run my nodeServer and Client sucessfully. But I want to connect its server to a proxy.
Here is the node client:
<html>
<head>
<script src="http://localhost:8000/socket.io/socket.io.js"></script>
<script src="http://code.jquery.com/jquery-1.6.2.min.js"></script>
<script>
var name = '';
var socket = io.connect('http://localhost:8000');
// at document read (runs only ones).
$(document).ready(function(){
// on click of the button (jquery thing)
// the things inside this clause happen only when
// the button is clicked.
$("button").click(function(){
// just some simple logging
$("p#log").html('sent message: ' + $("input#msg").val());
// send message on inputbox to server
socket.emit('chat', $("input#msg").val() );
// the server will recieve the message,
// then maybe do some processing, then it will
// broadcast it again. however, it will not
// send it to the original sender. the sender
// will be the browser that sends the msg.
// other browsers listening to the server will
// recieve the emitted message. therefore we will
// need to manually print this msg for the sender.
$("p#data_recieved").append("<br />\r\n" + name + ': ' + $("input#msg").val());
// then we empty the text on the input box.
$("input#msg").val('');
});
// ask for the name of the user, ask again if no name.
while (name == '') {
name = prompt("What's your name?","");
}
// send the name to the server, and the server's
// register wait will recieve this.
socket.emit('register', name );
});
// listen for chat event and recieve data
socket.on('chat', function (data) {
// print data (jquery thing)
$("p#data_recieved").append("<br />\r\n" + data.msgr + ': ' + data.msg);
// we log this event for fun :D
$("p#log").html('got message: ' + data.msg);
});
</script>
</head>
<body>
<input type="text" id="msg"></input><button>Click me</button>
<p id="log"></p>
<p id="data_recieved"></p>
</body>
</html>
Here is Server:
var check="check";
var io = require('socket.io').listen(8000);
// open the socket connection
io.sockets.on('connection', function (socket) {
// listen for the chat even. and will recieve
// data from the sender.
console.log('hello nahid');
socket.on('chat', function (data) {
// default value of the name of the sender.
var sender = 'unregistered';
check=sender;
// get the name of the sender
socket.get('nickname', function (err, name) {
console.log('Chat message by ', name);
console.log('error ', err);
sender = name;
});
// broadcast data recieved from the sender
// to others who are connected, but not
// from the original sender.
socket.broadcast.emit('chat', {
msg : data,
msgr : sender
});
});
// listen for user registrations
// then set the socket nickname to
socket.on('register', function (name) {
// make a nickname paramater for this socket
// and then set its value to the name recieved
// from the register even above. and then run
// the function that follows inside it.
socket.set('nickname', name, function () {
// this kind of emit will send to all! :D
io.sockets.emit('chat', {
msg : "naay nag apil2! si " + name + '!',
msgr : "mr. server"
});
});
});
});
They work well together. Now I want to have included server file into another html client like this:
<script type="text/javascript" src="nodeServer.js"></script>
In order to access variables in nodeServer.js. But The error "Uncaught ReferenceError: require is not defined "
What can I do to solve this and also I have this line code :
such that it knows what socket.io syntax is. But the error exists.
What should I do to make my html file know socket.io.js.
EDIT:
The last comment on the checked answer is what solved my issue. Thanks to #Houseman.

I'm pretty sure you can't just throw a Node.js file into a html DOM and expect it to work. Node.js files are run by Node.js, not by client-side html javascript.
This line <script src="http://localhost:8000/socket.io/socket.io.js"></script> is sufficient for loading the io object into your DOM, and make it accessible through javascript.
Remove this line:
<script type="text/javascript" src="nodeServer.js"></script>
, and you should be fine, if your server is running on port 8000. Your server code, however, doesn't seem to have the necessary components to actually run.
EDIT:
If you want to pass variables from your client to your server, or the other way around, use sockets, just like you're already doing.