CODEWITHSUNDEEP
node.jswebsocketmessaging
TheLovelySausage
TheLovelySausage

Reputation: 4094

Node.js WebSockets Send Message

I'm trying to come to terms with how WebSockets work in Node.js but I'm having some trouble with sending a message.

I have my WebSocket server configured as follows (index.js)

var ws = require("ws");
var wsserver = new ws.Server ({
   server: httpserver,
   port: 3030
});

wsserver.on (
   "connection", function connection(connection) {
      console.log("connection");
   }
);
wsserver.on (
   "open", function open(open) {
      console.log("open");
   }
);
wsserver.on (
   "message", function message(message) {
      console.log("message");
   }
);

This seems to be working ok because I can establish the connection using

var wscon = new WebSocket("ws://192.168.20.88:3030");

Which then gives me the connection output on the server. If I try to use send though nothing seems to happen and no error messages

wscon.onopen = function(open) {
  wscon.send("test message");
}

I must be missing something but I don't know what

Upvotes: 2

Views: 13523

Answers (2)

TheLovelySausage
TheLovelySausage

Reputation: 4094

I might have an answer for this but I'm not entirely sure just yet, I'm going to put this here just in case.

I think the problem is that the message listener is added to the wrong object (the server object), I tried to add the message listener to the connection object passed to the server and it seems to be working but I'm not 100% sure why

wsserver.on (
   "connection", function connection(connection) {
      console.log("connection");
      connection.on (
         "message", function message(message) {
            console.log("message : " + message);
         }
      );
   }
);

Upvotes: 3

KiwiCoder
KiwiCoder

Reputation: 1534

Which dependency works for me?

I have been using socketIO for a while now and it works perfectly for Node.JS API's / servers. There are millions of tutorials online for this framework and I'll tell you one them.

How to install?

If you use NPM as your package manager in Node.JS just down it with the following command:

npm install --save socket.io

In case you're using yarn you can install socketIO as following:

yarn add socket.io

Setup the socket server:

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

// Used for serving the HTML page (if used)
app.get('/', function(req, res){
  res.sendFile(__dirname + '/index.html');
});

// Listen for new connections
io.on('connection', function(socket){
  console.log('a user connected');
});

http.listen(3000, function(){
  console.log('listening on *:3000');
});

Now in index.html I add the following snippet before the :

<script src="/socket.io/socket.io.js"></script>
<script>
  var socket = io();
</script>

In your front-end you are able to fire of an event via the socket by calling the following function / code:

<script src="/socket.io/socket.io.js"></script>
<script src="https://code.jquery.com/jquery-1.11.1.js"></script>
<script>
  $(function () {
    var socket = io();
    $('form').submit(function(){
      socket.emit('chat message', $('#m').val());
      $('#m').val('');
      return false;
    });
  });
</script>

In our case we emitted an event called chat message. So in order to receive the value send over the socket connection we call the following code in our backend / api:

io.on('connection', function(socket){
  socket.on('chat message', function(msg){
    console.log('message: ' + msg);
  });
});

and that is basically how you use socket with the library SocketIO. Hope this helped fixing your issue!

Upvotes: 1

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