This tutorial will walk you through the creation of a simple Node.js and Socket.io example. It includes sending a message from an HTML page to a Node.js server and a message from a Node.js server to an HTML page.
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Create an HTML file with the basic required HTML tags:
<!doctype html> <html> <head> <title>Node.js and Socket.io</title> </head> <body> </body> </html>
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Include the Socket.io CDN in the
headsection:<script src='https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.4/socket.io.js'></script>
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Add a button to the
bodysection:<button id="fromClient">From Client</button>
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Before the close
bodytag add JavaScript that will initialize Socket.io, receive a Socket.io message from the Node.js server, and send a message to the Node.js server when the button is clicked:<script> var socket = io(); socket.on('fromServer', function(data) { console.log( 'ON: fromServer'); }); socket.on('time', function(data) { console.log( 'ON: time'); }); document.getElementById('fromClient').onclick = function(){ socket.emit('fromClient', { "message":"Sent from client!" }); console.log( 'EMIT: fromClient'); } </script>
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Create a
package.jsonfile and add Socket.io as a dependency:{ "name": "nodejs-socket", "version": "0.0.1", "description": "Sample communication from an HTML document to a Node.js server using Socket.io.", "dependencies": { "socket.io": "^2.0.4" } } -
Create a Node.js file names
app.jsand set up a basic http server:var http = require('http'); var fs = require('fs'); var index = fs.readFileSync( 'index.html'); var app = http.createServer(function(req, res) { res.writeHead(200, {'Content-Type': 'text/html'}); res.end(index); }); app.listen(3000);
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Before
app.listen(3000);add JavaScript to intermitantly send a messages to the HTML file and receive any messages sent form the HTML file:var io = require('socket.io').listen(app); setInterval(function sendTime() { io.emit('time', { time: new Date().toJSON() }); console.log( 'EMIT: time'); }, 10000); io.on('connection', function(socket) { socket.on('fromClient',function(data){ console.log( 'ON: fromClient'); socket.emit('fromServer', { message: 'Received message! Returning message!!' }); console.log( 'EMIT: fromServers'); }); });
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Start the Node.js app:
node app.js -
Open the HTML file using
http://localhost:3000, open the browser console, and test.
Full tutorial URL:
https://codeadam.ca/learning/nodejs-socket.html