For nodejs: Find out whether a client connection which might be proxied by front-end apache or nginx server OR is directly terminated by node is protected by SSL / TLS

isClientOnSSl.js

var util = require('utile'),
propUtil = require('./propUtil');

// Find out whether the client connection is encrypted
var isClientOnTls = function(req) {
	var isEncrypted = true;
	if(req.connection.encrypted === undefined) { // Derive from nodejs internals
		isEncrypted = false;
	}
	
	var forwardedHeader = propUtil.get(req, 'headers.x-forwarded-proto');
	if (forwardedHeader === 'https') { // Derive from front-end infrastructure injected header
		isEncrypted = true;
	} else {
		isEncrypted = false;
	}

	return isEncrypted;
}

exports.isClientOnTls = isClientOnTls;