I have 2 Raspberry Pi running on the same Network.
I am using one as a local web server for my house, I then have another one connected to some devices. I want them to both be able to communicate to each other via web sockets but am having some problems.
My server looks like this:
express = require('express'); //web server
app = express();
server = require('http').createServer(app);
io = require('socket.io').listen(server); //web socket server
server.listen(8080); //start the webserver on port 8080
app.use(express.static('public')); //tell the server that ./public/ contains the static webpages
io.sockets.on('connection', function (socket) { //gets called whenever a client connects
socket.on('Testing',function(data){
console.log("Testing connection");
});
});
My problem comes with the client connection I am really not sure what code to use to try and connect.
I have installed Express and Socket.io on my client and used this code:
console.log('1');
// Connect to server
var io = require('socket.io')
var socket = io.connect('http://192.168.1.138:8080', {reconnect: true});
console.log('2');
// Add a connect listener
socket.on('connect', function(socket) {
console.log('Connected!');
});
console.log('3');
But this leads to an error on the io.connect is not a function.
I am not really sure how to get the client to work so any advice is appreciated.
I should add that connecting to my webserver directly via the ip and port does load the webpages I have created successfully.
When using socket.io on the server side as a client you need to do var socket = require('socket.io-client')('http://192.168.1.138:8080', ...);. See https://www.npmjs.com/package/socket.io-client
Related
I want to implement Socket.IO in an Electron app, however I have found no documentation and no examples of how this could work.
If someone could explain to me how two or more clients could communicate via the electron app, I would be very grateful!
You know, the electron app will be running at end user.
So you should create Socket server at somewhere sth like Cloud server and your electron app should contain one socket.io client instance.
At Socket server
const app = require('express')();
const server = require('http').createServer(app);
const io = require('socket.io')(server);
io.on('connection', () => { /* … */ });
server.listen(3000);
And at frontend (your case Electron app side)
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io('http://localhost');
socket.on('connect', function(){});
socket.on('event', function(data){});
socket.on('disconnect', function(){});
</script>
or
// with ES6 import
import io from 'socket.io-client';
const socket = io('http://localhost');
So that users can communicate inside your Electron app.
I created my Socket server with Express, SocketIO and Redis
server.js
var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
var redis = require('redis');
server.listen(8890, function (e) {
console.log(e);
});
io.on('connection', function (socket) {
console.log("new client connected");
var redisClient = redis.createClient();
redisClient.subscribe('message');
redisClient.on("message", function(channel, message) {
console.log("mew message in queue "+ message + "channel");
socket.emit(channel, message);
});
socket.on('disconnect', function() {
redisClient.quit();
});
socket.on('connect_error', function() {
redisClient.quit();
});
});
From command line, I run node server.js. Its worked.
I also created a html file to connect to that server.
From Browser Console, I run io.connect('http://localhost:8890'). I got as the result
As I see, too much connections (requests).
What happens? What wrong from my code?
You have mismatched client and server versions causing the initial connection to fail and the older client is dumb enough to just keep trying over and over again. If you are using 2.0.4 on the server, then you must use that version for the client too. If you serve the client version directly from your server with:
<script src="http://localhost:8890/socket.io/socket.io.js"></script>
Then, the socket.io server will automatically give you the right client version.
Or, you can manually link to the right version on your CDN such as https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.4/socket.io.js. But client and server versions MUST match.
The advantage of getting the client directly from your own server is that anytime you update your server version of socket.io, the client version will automatically be upgraded for you and kept in perfect sync since the matching client version is built into the server version.
When I run the server, I wanted to be able to listen to the messages coming in to the server. However, the program/server is only set up to receive the calls without any notice
server.js
var express = require("express"),
program = require("program"),
app = express.createServer();
app.use(express["static"](__dirname + "/../"));
app.listen(5000);
//app.server to clients
program.init({
oscPort: xxxx,
oscHost: "xxx.xxx.xxx"
socketPort: app
});
You should add socket server because HTTP and Socket it's different protocols. There is a bunch of WebSocket servers like ws, socket.io so you could pick the one which is most suitable in your case. Here is an example how to use Socket.io with Express.
I have to make a system using socket.io there is the server in local (without port forwarded) (socket.io listen on the port 6255) and the client (socket.io.js) on a web server online hosted by hostinger.
I try to communicate between this two server but I have a connection timed out every time.
Connection on the server side : http://pastebin.com/xAFkserq
Connection on the client side : http://pastebin.com/ZMvbR3hC
Is it possible to communicate between two "networks" ? Or it's just a coding problem ?
Thanks for the help :)
Aren't you missing this?
io.on('connection', function(socket){
console.log('connected');
});
Also, have you tried following the examples in Socket.IO documentation?
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('a user connected');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
Working with sockets might be tricky, check if your network is blocking the exchange of messages somehow.
You shouldn't call connect on the client side with socket.io
On the client side simply do: var socket = io(); to connect back to the server, once the client JS has been served
Edit:
Since you're not using express and intend to just have a socket.io listener, the examples here should provide the information you need
I am using nodejs and express to create a basic chat app and I'm getting a network 404 error message when trying to initialize the socket.io object.
<script src="/javascripts/socket.io/socket.io.js-client"></script>
<script type="text/javascript">
var socket = io.connect();
</script>
Tha above code results in a 404 error for some polling call
"NetworkError" 404 Not Found - http://localhost:3000/socket.io/?EIO=3&transport=polling&t=1432851505880-89
I need the polling to run using the following url instead: http://localhost:3000/javascripts/socket.io/?EIO=3&transport=polling&t=1432851505880-89
because I am using express, but not sure how to accomplish this.
Server Side Code:
var app = express();
var server = require( "http" ).createServer( app );
var io = require("socket.io").listen(server);
server.listen(8888);
io.sockets.on('connection', function(socket){
socket.on('send message', function(data){
io.sockets.emit('new message', data);
});
});
module.exports = app;
I have been trying to troubleshoot this one for quite a while now with no success. I appreciate any advice. Commenting out the var socket = io.connect() resolves the error. Appreciate any advice.
Thanks
Your web page is apparently running on port 3000, but your socket.io server is listening on port 8888. The two must be the same port so it is no surprise that there is no response for a socket.io request on port 3000 (since your socket.io server is listening on port 8888).
Because the default URL it is trying is port 3000, then that must be the port that your web page is one and it must be served by a different web server. If that is the case, then you will need to do one of two things:
Combine the web server that serves your web pages with the socket.io server so the same server is taking care of both.
Specify the port in the client request and enable your socket.io server for cross-origin requests.
To specify the port in the client request, you can do this:
<script src="http://myserver.com:8888/socket.io/socket.io.js"></script>
<script type="text/javascript">
var socket = io("http://yourserver.com:8888");
</script>
Note, that this is requesting the client socket.io library from the express server where your socket.io server is (so it's using the same port that your socket.io server is running on).
If the HTML where socket.io client javascript is being served is not also being served by express at port 8888 (it looks like the html is coming from port 3000), you may just need to configure the socket.io client to point at the port where the server-side socket.io has been setup to listen (8888):
var socket = io.connect('localhost:8888');