Depending on your needs, you could allow both secure and unsecure connections and still only use one Socket.io instance.
You simply have to instanciate two servers, one for HTTP and one for HTTPS, then attach those servers to the Socket.io instance.
Server side :
// needed to read certificates from disk
const fs = require( "fs" );
// Servers with and without SSL
const http = require( "http" )
const https = require( "https" );
const httpPort = 3333;
const httpsPort = 3334;
const httpServer = http.createServer();
const httpsServer = https.createServer({
"key" : fs.readFileSync( "yourcert.key" ),
"cert": fs.readFileSync( "yourcert.crt" ),
"ca" : fs.readFileSync( "yourca.crt" )
});
httpServer.listen( httpPort, function() {
console.log( `Listening HTTP on ${httpPort}` );
});
httpsServer.listen( httpsPort, function() {
console.log( `Listening HTTPS on ${httpsPort}` );
});
// Socket.io
const ioServer = require( "socket.io" );
const io = new ioServer();
io.attach( httpServer );
io.attach( httpsServer );
io.on( "connection", function( socket ) {
console.log( "user connected" );
// ... your code
});
Client side :
var url = "//example.com:" + ( window.location.protocol == "https:" ? "3334" : "3333" );
var socket = io( url, {
// set to false only if you use self-signed certificate !
"rejectUnauthorized": true
});
socket.on( "connect", function( e ) {
console.log( "connect", e );
});
If your NodeJS server is different from your Web server, you will maybe need to set some CORS headers. So in the server side, replace:
const httpServer = http.createServer();
const httpsServer = https.createServer({
"key" : fs.readFileSync( "yourcert.key" ),
"cert": fs.readFileSync( "yourcert.crt" ),
"ca" : fs.readFileSync( "yourca.crt" )
});
With:
const CORS_fn = (req, res) => {
res.setHeader( "Access-Control-Allow-Origin" , "*" );
res.setHeader( "Access-Control-Allow-Credentials", "true" );
res.setHeader( "Access-Control-Allow-Methods" , "*" );
res.setHeader( "Access-Control-Allow-Headers" , "*" );
if ( req.method === "OPTIONS" ) {
res.writeHead(200);
res.end();
return;
}
};
const httpServer = http.createServer( CORS_fn );
const httpsServer = https.createServer({
"key" : fs.readFileSync( "yourcert.key" ),
"cert": fs.readFileSync( "yourcert.crt" ),
"ca" : fs.readFileSync( "yourca.crt" )
}, CORS_fn );
And of course add/remove headers and set the values of the headers according to your needs.