Example:
var WebSocket = require('ws');
var ws = new WebSocket('ws://echo.websocket.org/', {protocolVersion: 8, origin: 'http://websocket.org'});
ws.on('open', function() {
console.log('connected');
ws.send(Date.now().toString(), {mask: true});
});
ws.on('close', function() {
console.log('disconnected');
// What do I do here to reconnect?
});
What should I do when the socket closes to reconnect to the server?
You can wrap all your setup in a function and then call it from the close handler:
var WebSocket = require('ws');
var openWebSocket = function() {
var ws = new WebSocket('ws://echo.websocket.org/', {protocolVersion: 8, origin: 'http://websocket.org'});
ws.on('open', function() {
console.log('connected');
ws.send(Date.now().toString(), {mask: true});
});
ws.on('close', function() {
console.log('disconnected');
openWebSocket();
});
}
openWebSocket();
However, there is likely more logic you want here (what if the close was on purpose? what happens if you try to send a message while its reconnecting?). You're probably better off using a library. This library suggested by aembke in the comments seems reasonable. socket.io is not a bad choice (and it gives you non-WebSocket transports).
Related
when i print client in console logconsole.log(client ${client}); it shows undefined.
I think i should do something in my client code but don't know what.
Server code -
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });
wss.on('connection', function connection(ws, request, client) {
console.log(`client ${client}`);
ws.on('message', function message(msg) {
console.log(`Received message ${msg}`);
});
});
client code-
const Websocket = require('ws');
const ws = new Websocket('ws://localhost:8081');
function noop() {}
ws.on("message", function(event){
console.log(event);
});
const ping = function() {
ws.ping(noop);
}
setInterval(ping, 30000);
ws doesn't support client out of the box.
See: https://www.npmjs.com/package/ws#client-authentication
the gist of it is that you need to use an HTTP server to listen to any connections (not using ws to listen) and "manual" emit the connection event with additional data (like client).
I have a NodeJS web app running. I have a WebSocketServer running. I can communicate with my app via a WebSocket connection made from my javascript on the client machine fine. Here's the nodejs server-side code snippet of relevance:
var WebSocket = require('ws');
var WebSocketServer = require('ws').Server;
var server = app.listen(process.env.VCAP_APP_PORT || 3000, function () {
console.log('Server started on port: ' + server.address().port);
});
wss.on('connection', function (ws) {
ws.on('message', function (message, flags) {
if (flags.binary) {
var value1 = message.readDoubleLE(0);
var value2 = message.readInt16LE(8);
var value3 = message.readInt8(10);
//message.writeDoubleLE(8.5,0);
ws.send(message, {
binary: true
});
} else {
if (message == "injest") {
ws.send("requested: " + message);
} else if (message == "something") {
wss.clients[0].send('server side initiated call');
} else {
ws.send("received text: " + message);
}
}
});
// ws.send('something'); // Sent when connection opened.
});
So you see, all very simple.
Here 's my problem. How can I access this WebServer from the NodeJS code of the server-side app itself?
I tried the below:
var ws = new WebSocket("ws://localhost:443");
ws.on('message', function (message) {
wss.clients[0].send('server side initiated call 1 ');
});
ws.on('close', function (code) {
wss.clients[0].send('server side initiated call 2 ');
});
ws.on('error', function (error) {
wss.clients[0].send(error.toString());
});
ws.send("k");
The error function is triggered with ECONNREFUSED 127.0.0.1:443.
I specified no port when I set the server up. If I do then the calls to the server from my client html page fail.
So in brief how can I set up a WebSocket client in NodeJS to access a WebSocketServer created in that app?
Do not use localhost. Substitute the 127.0.0.1 for it.
Instantiate the Server
let WebSocketServer = require("ws").Server;
let ws = new WebSocketServer({port: 9090});
ws.on('connection', function (ws) {
console.log(nHelp.chalk.red.bold('Server WebSocket was connected.'));
// Add the listener for that particular websocket connection instance.
ws.on('message', function (data) {
//code goes here for what you need
});
ws.on('close', function () {
console.log('websocket connection closed!');
});
});
You can open other ports and routes (example for Express) in the same file, or other ports for WS as well btw.
The above is not code for Secure WS server for TLS. that is a bit different.
I have a Nodejs simple server using ws module.
When client connected to server and then I disconneted internet from PC but in server close event not emitted.
Example is bellow:
var WebSocketServer = require('ws').Server
, wss = new WebSocketServer({port: 8080});
wss.on('connection', function(ws) {
ws.on('message', function(message) {
console.log('received: %s', message);
});
ws.send('something');
ws.on('close', function() {
console.log('closed.');
});
});
Try to add event "error" :
ws.on("error", function(error) {
// Manage error here
console.log(error);
});
If this doesn't work, use Socket.io (npm install socket.io)
I found a simple websocket server in nodejs.
var WebSocketServer = require('ws').Server,
wss = new WebSocketServer({
port: 8080
});
var clientsCount = 0;
console.log('clients,rss,heapTotal,heapUsed');
setInterval(function() {
console.log('%d,%d,%d,%d', clientsCount,
process.memoryUsage().rss,
process.memoryUsage().heapTotal,
process.memoryUsage().heapUsed);
}, 10000);
wss.on('connection', function(ws) {
clientsCount++;
console.log(clientsCount);
ws.on('message', function(message) {
console.log(message);
});
ws.send('something');
ws.on('close', function() {
clientsCount--;
})
});
The script works fine but sometimes when a client connects and sends a data, the server doesn't accept the message; ws.on('message', function(message){...}); doesn't seem to trigger when the event occurs.
I have a socket.io server running and a matching webpage with a socket.io.js client. All works fine.
But, I am wondering if it is possible, on another machine, to run a separate node.js application which would act as a client and connect to the mentioned socket.io server?
That should be possible using Socket.IO-client: https://github.com/LearnBoost/socket.io-client
Adding in example for solution given earlier. By using socket.io-client https://github.com/socketio/socket.io-client
Client Side:
//client.js
var io = require('socket.io-client');
var socket = io.connect('http://localhost:3000', {reconnect: true});
// Add a connect listener
socket.on('connect', function (socket) {
console.log('Connected!');
});
socket.emit('CH01', 'me', 'test msg');
Server Side :
//server.js
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
io.on('connection', function (socket){
console.log('connection');
socket.on('CH01', function (from, msg) {
console.log('MSG', from, ' saying ', msg);
});
});
http.listen(3000, function () {
console.log('listening on *:3000');
});
Run :
Open 2 console and run node server.js and node client.js
After installing socket.io-client:
npm install socket.io-client
This is how the client code looks like:
var io = require('socket.io-client'),
socket = io.connect('http://localhost', {
port: 1337,
reconnect: true
});
socket.on('connect', function () { console.log("socket connected"); });
socket.emit('private message', { user: 'me', msg: 'whazzzup?' });
Thanks alessioalex.
const io = require('socket.io-client');
const socket_url = "http://localhost:8081";
let socket = io.connect(socket_url);
socket.on('connect', function () {
socket.emit("event_name", {});
});
Yes you can use any client as long as it is supported by socket.io. No matter whether its node, java, android or swift. All you have to do is install the client package of socket.io.
Client side code: I had a requirement where my nodejs webserver should work as both server as well as client, so i added below code when i need it as client, It should work fine, i am using it and working fine for me!!!
const socket = require('socket.io-client')('http://192.168.0.8:5000', {
reconnection: true,
reconnectionDelay: 10000
});
socket.on('connect', (data) => {
console.log('Connected to Socket');
});
socket.on('event_name', (data) => {
console.log("-----------------received event data from the socket io server");
});
//either 'io server disconnect' or 'io client disconnect'
socket.on('disconnect', (reason) => {
console.log("client disconnected");
if (reason === 'io server disconnect') {
// the disconnection was initiated by the server, you need to reconnect manually
console.log("server disconnected the client, trying to reconnect");
socket.connect();
}else{
console.log("trying to reconnect again with server");
}
// else the socket will automatically try to reconnect
});
socket.on('error', (error) => {
console.log(error);
});
something like this worked for me
const WebSocket = require('ws');
const ccStreamer = new WebSocket('wss://somthing.com');
ccStreamer.on('open', function open() {
var subRequest = {
"action": "SubAdd",
"subs": [""]
};
ccStreamer.send(JSON.stringify(subRequest));
});
ccStreamer.on('message', function incoming(data) {
console.log(data);
});