HTTPS on same port as HTTP? - node.js

Question

I'm writing an HTTP/HTTPS proxy server in Node.JS, I want the server to handle HTTPS traffic on the same port as HTTP.
The below image explains why I want to do this, the user can just check the box...
I realize that I can't have 2 servers listening on the same port, but is there a way to setup a main server that forwards the traffic to either HTTP or HTTPS traffic?
Something like this:
http.createServer(myHTTPCallback).listen(3129, '127.0.0.1');
https.createServer(myHTTPSCallback).listen(3130, '127.0.0.1');
//Then a main server that will listen for both kinds of traffic
main.createServer(function(req, res){
if(/*Traffic is HTTPS*/){
//Forward to 127.0.0.1:3130
}
else{
//Forward to 127.0.0.1:3129
}
}).listen(3128, '192.168.0.2');
How would I code the above?
EDIT - As per #Chris Jester-Young answer
I created this simple server, but I only receive output for HTTP requests. Also breakpoints or console logs don't trace:
var http = require('http');
http.createServer(function(req, res){
res.write('<h1>Resquest Received</h1>');
res.write('<span>Requested URL = ' + req.url + '</span>');
res.end();
}).listen(3128);

Answer 1

You don't have to listen to both HTTP and HTTPS on the same port, in your specific case of writing a proxy server. Browsers connect to proxy servers via HTTP, whether for proxying HTTP or HTTPS requests. HTTPS requests use the CONNECT HTTP method to open a direct connection to the HTTPS server---that CONNECT request is still done in the unencrypted portion of the proxy traffic.
Edit: Here's what I think your code should look like:
http.createServer(function (request, response) {
// Handle normal requests here
}).on('connect', function (request, socket, head) {
// Handle CONNECT requests here
}).listen(3128);