Why am I not getting any response from socket.io connection event
Question
I have just started with socket.io and to practice I wanted to create a server whose output tells me 'A user connected' every time a connection with the client is established. I thought that a connection is established just by starting the server and going to localhost:5000 . After that I would see the output message from the connection in my console.
const express = require('express') const app = express() app.get('/', (req, res) => { res.send('I am alive') }) PORT = process.env.PORT || 5000 const server = app.listen( PORT, () =>{ console.log(`Listening to http://localhost:${PORT}`)}) const io = require('socket.io')(server) io.on('connection', function(socket) { console.log('A user connected');})
For this process, I type node server.js , wait until the message Listening to http://localhost:5000 appears and then I go to the page. But when I navigate to the page I see no console message. Is a html file necessary for the message to appear? Or am I not seeing a important step? I have seen some tutorials but all of them use a html file, and I wanted to avoid that step. Thanks a lot!
2 answers
solution1
1 ACCPTED 2020-06-21 06:28:05
On server by writing this code
io.on('connection', function(socket) {
console.log('A user connected');
})
you are listening to the connection and somebody, somewhere has to connect to the socket of this server on same url as your server is for example like this
var socket = require('socket.io-client')('http://localhost:5000');
socket.on('connect', function () {
socket.on("FromAPI", data => {
setResponse(data);
});
socket.emit("FromAPI")
}
When you make socket connection anywhere either in html or any other code the console.log() will print data on server
solution2
0 2020-06-21 06:22:26
The code you shared is the server end you need to setup client as well.
Client End:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.3.0/socket.io.js"></script>
<script>
var socket = io('http://localhost:<PORT>');
</script>
</body>
</html>
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