forwarded-host/index.js

Determine the host of the originating request

'use strict';

const debug = require('debug');
const info = debug('forwarded-host');

module.exports = function parse(req) {
	if (!req) {
		throw new TypeError('argument req is required')
	}

	const headers = req.headers;
	info (headers);

	const xForwardedHost = headers['x-forwarded-host'];
	const xForwardedProto = headers['x-forwarded-proto'];
	const xForwardedPort = headers['x-forwarded-port'];
	const headerPort = headers['host'];

	var proto = xForwardedProto || req.protocol;
	var host, url;

	if (xForwardedHost) {
		var port = xForwardedPort;
		if (port) port = +port;

		host = xForwardedHost;
		if (port && port !== 80 && port !== 443) host += ':' + port;
		if (!proto) {
			if (port === 443) proto = 'https';
			else proto = 'http';
		}
	} else {
		host = headers['host'];
		if (!proto) proto = 'http';
	}

	url = proto + '://' + host;

	info(url);
	return url;
}