cors proxy in nodejs

cors-proxy.js

var http = require('http');
var connect = require('connect');
var httpProxy = require('http-proxy');

var proxy = module.exports = function(options){
    return function (req, res) {
        var proxy = new httpProxy.HttpProxy(req, res);
        
        var headerFields = null;
        
        if(req.method === 'OPTIONS') {
            /* CORS Preflight request */
            if(!req.headers.origin) {
                fail;
            }
            
            if(!req.headers['access-control-request-method']) {
                fail;
            }
            
            req.headers['access-control-allow-origin'] = req.headers.origin;
            req.headers['access-control-allow-credentials'] = 'true';
            req.headers['access-control-allow-methods'] = req.method;
            req.headers['access-control-allow-headers'] =
                req.headers['access-control-request-headers']
            
        } else {
            req.headers['Access-Control-Allow-Origin'] = '*';
            req.headers['Access-Control-Allow-Methods'] =
                'GET, OPTIONS, HEAD, POST, PUT, DELETE';
            req.headers['Access-Control-Allow-Headers'] = 
            'X-Requested-With';
        }
        
        // Put your custom server logic here, then proxy
        proxy.proxyRequest(options.port, 'localhost', req, res);
    }
}