Step 1: server
I've created a simple server with Node & Socket.io which declares a namespace under /my-namespace. Once somebody connects, emit a confirmation msg as CONNECT_ACK and emit 3 seconds later another event (for example SOME_EVENT) with a payload:
const express = require('express');
const http = require('http');
const socketIO = require('socket.io');
let app = express();
let server = http.createServer(app);
server.listen(3000, () => {
console.log('server listening on port 3000');
let io = new socketIO(server);
io.of('/my-namespace').on('connection', (socket) => {
console.log('welcome!');
socket.emit('CONNECT_ACK');
setTimeout(() => {
io.of('/my-namespace').emit('SOME_EVENT', { a: 4 });
}, 3000);
});
});
Step 2: client
Then, I created the smallest client side which just connects to the namespace and logs when it receives CONNECT_ACK or SOME_EVENT
<!doctype html>
<html>
<head>
<title>example</title>
<script src="./node_modules/socket.io-client/socket.io.js"></script>
<script>
const endPoint = "http://localhost:3000/my-namespace";
io(endPoint)
.on('CONNECT_ACK', () => { console.log("I've connected"); })
.on('SOME_EVENT', (data) => { console.dir(data); });
</script>
</head>
<body>
</body>
</html>
Step 3: Checking everything is awesome
Running the client node index.js and serving the html (I use Python Simple Server) I got the desired in both consoles:
Step 4. Understanding whats going on here
Now, when I opened the Network Chrome tab I started writing this long post. These are the requests:
[WebSocket Protocol]: GET to /socket.io (not to /my-channel) receiving some confirmation bits; POST again to /socket.io including those confirmation bits. OK.
[I don't get this]: again a GET to /socket.io including the confirmation bits which now resolves to the CONNECT_ACK event: ÿ40ÿ40/my-namespaceÿ42/my-namespace,["CONNECT_ACK"]. This is the only event I'm going to receive this way.
[WS]: A GET to /socket.io indicating it's a websoket returns me a 101 (Switching Protocols) and I can recieve the msgs as: 42/my-namespace,["SOME_EVENT",{"a":4}]
which is the event I send from the server & some 2s or 3s periodically
[I don't get this too]: again a GET to /socket.io including the confirmation bits which now resolves to this thing: ÿ6
Why does the client asks for socket.io instead of /my-channel?
Why there is a GET after the WS handshake which receives CONNECT_ACK msg?
I understand that the "inmortal" request which resolves in 101 is the socket itself, and those 2s and 3s are just periodical checks.
Why does all the events start by 42 (I've checked this does not change)
What is that final GET? is it part of the WS protocol?
Why does the client asks for socket.io instead of /my-channel?
When setting up socket.io-server, socket.io will set itself to intercept any request to /socket.io in order to work. Namespaces use the same notation as paths in HTTP, but mean completely different things, and connecting to a namespace performs the same HTTP request to /socket.io, but with a different namespace argument in it.
Why there is a GET after the WS handshake which receives CONNECT_ACK msg?
I can't be sure of this one, but this probably arrived to the server before the WS request, and sent the CONNECT_ACK via polling instead.
Why does all the events start by 42 (I've checked this does not change)
According to this GitHub issue, it defines the packet as a message (4) of type event (2). Personally, I suspect the 4 is actually the protocol version, currently 4, as it's the only reference to that number in the docs except in packet types (which must then be 2).
What is that final GET? is it part of the WS protocol?
Not sure again, but possibly a confirmation that the WS connection has been established and a way for socket.io to confirm that it should switch from polling to WS and start sending the events there.
Related
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 have a Node.js script which is supposed to regularly access a SailsJS application via a socket connection. Client and server run on physically different machines on different networks. The SailsJS application is proxied behind nginx. That works in general. However, at random times, the connection is established but the first post request within the websocket connection never reaches its destination.
The code looks basically like this:
var socketIOClient = require('socket.io-client');
var sailsIOClient = require('sails.io.js');
var io = sailsIOClient(socketIOClient);
io.sails.url = 'https://foo.foo:443';
io.sails.rejectUnauthorized = false;
io.socket.on('connect', function() {
console.log("Connected!")
io.socket.post('/someroute', { someOptions: "foo" } ,
function(data) {
console.log(data);
});
});
io.socket.on('disconnect', function(){
console.log("Disconnected!");
});
io.socket.on('connect_error',function () {
console.log("connect_error!");
});
In case of a failure, simply nothing happens after console.log("Connected!"). Nothing appears in nginx's logs (in contrast to successful cases), the callback of io.socket.post never gets executed.
The most important question for me is: At which side is the problem? Client or server?
How can I debug this and narrow down the problem? Could it be a networking issue? Or something wrong the configuration, implementation or with the script itself?
I have a windows application (Built on C# as windows service) that sends data to NodeJs Net Socket, So since Socket.IO helps making a Web Application a live one , without the need of reload. How can i allow Socket.IO stream the received data from NodeJs Net Socket to the Web Application , in the exact moment the Net Socket receives data from C#?
So in the code that receives the socket data from C#:
var net = require('net');
net.createServer(function (socket) {
socket.on('data', function (data) {
broadcast(socket.name + "> \n" + data + " \n", socket);
socket.end("<EOF>");
//send data to web interface , does it work that way?
//SomeFooToSendDataToWebApp(Data)
});
});
Further more for the Socket.IO i have those lines , which i cant really figure out how to deal with them:
//Should it listen to net socket or web socket?
server.listen(8080);
// Loading socket.io
var io = require('socket.io').listen(server);
// It works but only for one request
io.sockets.on('connection', function (socket2) {
socket2.emit('message' , 'Message Text');
});
P.S: I am new to nodejs & socket.io , so if its possible as well to explain their behavior.
Edit 1 : My Front End Javascript to check it if it has any problems:
//for now it listens to http port , which Socket.IO listens to
var socket = io.connect('http://localhost:8080');
var myElement = document.getElementById("news");
socket.on('message', function(message) {
document.getElementById("news").innerHTML = message;
})
Edit 2 : Did follow jfriend00's answer as it seems my previous code tries were trying to send messages to an unknown socket, i only added this since i needed it to be sent to all the connected clients , so only one line fixed it !
socket.on('data', function (data) {
broadcast(socket.name + "> \n" + data + " \n", socket);
socket.end("<EOF>");
//send data to web interface , does it work that way?
//The Added code here:
io.emit('message',data + " more string");
});
It's a bit hard to tell exactly what you're asking.
If you have some data you want to send to all connected socket.io clients (no matter where the data came from), then you can do that with:
io.emit("someMessage", dataToSend);
If you want to send to only one specific connected client, then you have to somehow get the socket object for that specific client and then do:
socket.emit("someMessage", dataToSend);
How you get the specific socket object for the desired connected client depends entirely upon how your app works and how you know which client it is. Every socket connection on the server has a socket.id associated with it. In some cases, server code uses that id to keep track of a given client (such as putting the id in the session or saving it in some other server-side data). If you have the id for a socket, you can get to the socket with the .to() method such as:
io.to(someId).emit("someMessage", dataToSend);
Your question asked about how you send data received from some C# service over a normal TCP socket. As far as sending it to a socket client, it does not matter at all where the data came from or how you received it. Once you have the data in some Javascript variable, it's all the same from there whether it came from a file, from an http request, from an incoming TCP connection in your C# service, etc... It's just data you want to send.
You can try the following, simple server:
const io = require('socket.io')(8080);
io.on('connection', socket => {
console.log('client connected');
socket.on('data', data => {
io.emit('message', data);
});
});
console.log('server started at port 8080');
It should work if I understand the problem correctly.
And maybe document.getElementById("news").innerHTML += message; in the html client code to see what really happens there?
socket2 means your client which just connected. So you can store these connections to send data to them (helpful for broadcast).
If you get data from windows service via some polling mechanism, on this step you can send this message to your connected clients. So keep your connections in a array to send specific messages each client afterwards
I want to serve socket connections from a Flash browser client, and therefore I need to add support for the policy-request-file protocol. I can't run the policy-file-request service on the default port 843 because of firewalls etc. The only option I have is to server the protocol on port 80, beside my HTTP server.
My app is written in node.js and the following code works:
var httpServer = http.createServer();
net.createServer(function(socket){
httpServer.emit('connection', socket);
}).listen(80);
I open a socket server on port 80, and for now I just emit the connection event on the httpServer, no problem so far. Now I want to check if the new socket is a policy-file-request which will just send the plain string <policy-file-request /> over a TCP connection. When I notice this string I know it isn't HTTP and I can return the crossdomain file and close the socket. So what I try now is this:
net.createServer(function(socket){
socket.once('readable', function(){
var chunk = socket.read(1);
// chunk[0] === 60 corresponds to the opening bracket '<'
if(chunk !== null && chunk[0] === 60) {
socket.end(crossdomain);
} else {
socket.unshift(chunk);
httpServer.emit('connection', socket);
}
});
}).listen(80);
Now I check if the first byte is the opening bracket '<' and then write the crossdomain file to the socket. Otherwise I unshift the chunk onto the stream and emit the socket as a connection on the HTTP-server. Now the problem is that the HTTP-server doesn't emit a request event anymore and my regular HTTP-requests aren't handled as a result.
I also tried this solution but with no success either:
httpServer.on('connection', function(socket){
socket.once('data', function(chunk){
if(chunk[0] === 60) {
socket.end(crossdomain);
}
})
});
When the socket emits the data event, the readyState of the socket is already 'closed' and a clientError event is already thrown by the httpServer. I searched everywhere and didn't found a solution. I also don't want to pipe the data through another socket to another port where my HTTP server is running locally, because that adds to many, unnecessary overhead I think. Is there a clean way to do this in node.js? I tested all this on node.js version 0.10.26.
I am trying to enable tcp, http and websocket.io communication on the same port. I started out with the tcp server (part above //// line), it worked. Then I ran the echo server example found on websocket.io (part below //// line), it also worked. But when I try to merge them together, tcp doesn't work anymore.
SO, is it possible to enable tcp, http and websockets all using the same port? Or do I have to listen on another port for tcp connections?
var net = require('net');
var http = require('http');
var wsio = require('websocket.io');
var conn = [];
var server = net.createServer(function(client) {//'connection' listener
var info = {
remote : client.remoteAddress + ':' + client.remotePort
};
var i = conn.push(info) - 1;
console.log('[conn] ' + conn[i].remote);
client.on('end', function() {
console.log('[disc] ' + conn[i].remote);
});
client.on('data', function(msg) {
console.log('[data] ' + conn[i].remote + ' ' + msg.toString());
});
client.write('hello\r\n');
});
server.listen(8080);
///////////////////////////////////////////////////////////
var hs = http.createServer(function(req, res) {
res.writeHead(200, {
'Content-Type' : 'text/html'
});
res.end(['<script>', "var ws = new WebSocket('ws://127.0.0.1:8080');", 'ws.onmessage = function (data) { ws.send(data); };', '</script>'].join(''));
});
hs.listen(server);
var ws = wsio.attach(hs);
var i = 0, last;
ws.on('connection', function(client) {
var id = ++i, last
console.log('Client %d connected', id);
function ping() {
client.send('ping!');
if (last)
console.log('Latency for client %d: %d ', id, Date.now() - last);
last = Date.now();
};
ping();
client.on('message', ping);
});
You can have multiple different protocols handled by the same port but there are some caveats:
There must be some way for the server to detect (or negotiate) the protocol that the client wishes to speak. You can think of separate ports as the normal way of detecting the protocol the client wishes to speak.
Only one server process can be actually listening on the port. This server might only serve the purpose of detecting the type of protocol and then forwarding to multiple other servers, but each port is owned by a single server process.
You can't support multiple protocols where the server speaks first (because there is no way to detect the protocol of the client). You can support a single server-first protocol with multiple client-first protocols (by adding a short delay after accept to see if the client will send data), but that's a bit wonky.
An explicit design goal of the WebSocket protocol was to allow WebSocket and HTTP protocols to share the same server port. The initial WebSocket handshake is an HTTP compatible upgrade request.
The websockify server/bridge is an example of a server that can speak 5 different protocols on the same port: HTTP, HTTPS (encrypted HTTP), WS (WebSockets), WSS (encrypted WebSockets), and Flash policy response. The server peeks at the first character of the incoming request to determine if it is TLS encrypted (HTTPS, or WSS) or whether it begins with "<" (Flash policy request). If it is a Flash policy request, then it reads the request, responds and closes the connection. Otherwise, it reads the HTTP handshake (either encrypted or not) and the Connection and Upgrade headers determine whether it is a WebSocket request or a plain HTTP request.
Disclaimer: I made websockify
Short answer - NO, you can't have different TCP/HTTP/Websocket servers running on the same port.
Longish answer -
Both websockets and HTTP work on top of TCP. So you can think of a http server or websocket server as a custom TCP server (with some state mgmt and protocol specific encoding/decoding). It is not possible to have multiple sockets bind to the same port/protocol pair on a machine and so the first one will win and the following ones will get socket bind exceptions.
nginx allows you to run http and websocket on the same port, and it forwards to the correct appliaction:
https://medium.com/localhost-run/using-nginx-to-host-websockets-and-http-on-the-same-domain-port-d9beefbfa95d