I am trying to make a proxy between sockets and websockets. I receive requests on socket server and I want to proxy them to websocket clients, however websocket.ws.send appears to be undefined. What would be the correct way of doing this? How to call ws.send() from outside of the object?
var WebSocketServer = require('ws').Server,
wss = new WebSocketServer({port: 8001}),
var net = require('net')
websocket = wss.on('connection', function(ws) {
ws.on('message', function(message) {
console.log('received: %s', message);
});
ws.send("NEW USER JOINED");
});
var socketServer = net.createServer(function(socket) {
socket.on("data", function(data){
console.log("Received: "+data)
websocket.ws.send("Message")
});
});
socketServer.listen(1337, '127.0.0.1');
The problem you have is that ws is a single web socket for one connection. It is not a property on the websocket object, but an argument to a callback you define. Each time someone connects you will get a connection event which will execute your callback, allowing you to bind a function to that specific web socket for the message event.
You either need to store the ws object in a variable that the socket server can access or you could broadcast to all clients.
wss.clients.forEach(function each(client) {
client.send(data);
});
This will work fine if you only have one client, however if you have multiple connections to both the websocket and socket server then you need to use a method of identifying connections on both so that you can locate the websocket connection you need to send data to.
Related
I'm building a server which acts as a proxy between a browser and a third party service using websockets. the general sequence is
Browser connects to server via websocket
After authentication , the server connects via websocket to a third party service.
the third party service sends a message to the server which relays it back to the browser
One problem i'm trying to solve is to disconnect the websocket from server -> third party service whenever the socket from the browser disconnects.
To that extent, i'm thinking of maintaining an object like the below
var thirdPartySockets = {};
whenever a client socket connects :
var ServerSocket = connectToThirdParty (clientSocketId, URL);
thirdPartySockets [clientSocketId] = ServerSocket;
The code for connectToThirdParty
var connectToThirdParty = function(clientSocketId, URL){
var client = new WebSocketClient();
client.on('connectFailed', function(err) {
console.log('connection failed')
});
client.on('connect', function(connection) {
connection.on('error', function(err) {
});
connection.on('close', function() {
// attempt reconnection
});
connection.on('message', function(message) {
// send back to client
});
});
client.connect(URL);
return client
}
The problem here is i'm trying to disconnect the server socket whenever the browser socket disconnects. I cannot seem to access the thirdPartySocket list object in the disconnect event.
var thirdPartySockets = {};
io.on('connection', function(socket){
socket.on('disconnect', function(){
// how do i access the thidPartySockets object here?
});
});
Are there better ways to handle this situation?
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.
node.js WebSocket example code snippet
I have a simple node.js application using express. Now everytime a client connects to the node server I see the string 'new client connected' but I would like to know which IP the new client had.
var WebSocketServer = require('ws').Server;
var connIds = [];
var server = require('http').createServer(app).listen(80);
// set up the websocket server
var wss = new WebSocketServer( { server: server } );
wss.clientConnections = {};
// websocket server eventlisteners and callbacks
wss.on('connection', function (connection) {
console.log('wss.on.connection - new client connected');
...
See the code at:
https://github.com/qknight/relais.js/blob/master/relais.js/server.js#L159
question
The object connection has properties but I don't understand how to query them or what they are. All I want is to print the client IP and maybe, if existent, other similar properties as well.
How do I do that?
Remote IP is a property of the pre-upgrade connection:
var wss = new WebSocketServer({port: 9876});
wss.on('connection', function(ws) {
console.log(ws.upgradeReq.connection.remoteAddress);
});
i don't recall how i found it, but i know it took me a while; i wish the docs were as good as the code...
UPDATE:
WS has moved some things around, so here's an updated example of how to get the original HTTP info in current code. Note the 2nd argument to the connection event handler:
wss.on('connection', function conn(ws, req) {
var ip = req.connection.remoteAddress;
console.info(ip);
});
I am trying to make a console based node.js application which simulates 1000/+ clients Connections to an existing node.js based TCP server app.
Update: With the current version of this code^ I am getting an error TypeError: cannot call method 'write' of undefined at: connx[connNos].Write(str). I guess I will have to rethink/rewrite this piece of code; any pointers are welcome.
Till now this is what I came up with but this doesn't work as implied:
var net = require('net');
var HOST = '127.0.0.1';
var PORT = 7000;
var timeout = 30000;
var connx = [];
for(var connNos = 0; connNos < 10; connNos++){
connx[connNos] = net.createConnection(PORT,HOST);
//connx.push(connx[connNos]);
connx[connNos].on('connect', function(err){
console.log('Client: Connected');
});
connx[connNos].on('error', function(data){
console.log('>> ' + data);
});
connx[connNos].on('close', function(){
console.log('Client: Conn Closed');
process.exit();
});
process.stdin.on('data', function(data){
console.log('sending data..');
//connection.write(data);
var str = "486229^4049^1018436^D^2013-04-01 00:02:09^22.715939100^88.374148220^27238^0^308^0^192.168.1.1^1^2013-04-01 19:49:04";
connx[connNos].write(str);
//connection.end();
});
process.stdin.resume();
}
Any help will be appreciated
TIA :D
From the doc
net.createConnection(options, [connectionListener])#
Constructs a new socket object and opens the socket to the given location. When the socket is established, the 'connect' event will be emitted.
For TCP sockets, options argument should be an object which specifies:
port: Port the client should connect to (Required).
host: Host the client should connect to. Defaults to 'localhost'.
localAddress: Local interface to bind to for network connections.
For UNIX domain sockets, options argument should be an object which specifies:
path: Path the client should connect to (Required).
I guess
connx[connNos] = net.createConnection(PORT,HOST);
should be
connx[connNos] = net.createConnection({port:PORT,host: HOST});
Think async, most probably reason is that when you call socket.write socket connection was not estanblished. You should check connection before call or you can put code in connection listener.
I have a socket.io connection to connect to server and client,
It work fine.
Now when I try to reconnect it on disconnect from server it get connected but then socket.on('message' doesnt get fired any more.
I checked it from server side it is pushing that message.
Please suggest me some thing I am out of ideas now.
I am sure that problem is on client side socket.on message
Client side code
var socket = new io.Socket('some host name',{port:80,rememberTransport:true});
socket.on('connect', function(){
clearInterval(socketInterval);
});
socket.on('message', function(obj)
{
alert("meg from server");
});
socket.on('disconnect', function()
{
socketInterval=setInterval("socket.connect()",5000);
});
socket.connect();
I don't know node.js, but it looks like syntax error, haven't you forgot the right paratheses?
socket.on('connect', function(){
clearInterval(socketInterval);
});
socket.on('message', function(obj)
{
alert("meg from server");
});
socket.on('disconnect', function()
{
socketInterval=setInterval("socket.connect()",5000);
});
it would appear that the "problem" most likely is on the server side. The server has two ways to send messages to the client (emit and broadcast). If you are doing a one to one message, most people use emit. I am assuming that you built a chat server which stores the sessionIds of the client. It works fine with the initial connection because the server has the correct sessionId, but let's say connection is lost and you reestablish connection, now the server tries to send a message to the client. If your server stored the initial sessionId, say in an array, and attempts to use the original sessionId to emit a message, it will fail because reconnection causes a new sessionId to be created.
The solution in this case is to remove the previous sessionId from the array and add the new sessionId upon reconnection.