proxy.js

// Usage from some other file:
//
// var app = require('./proxy')({proxyUrl: '//your-remote.com', proxyBase: '/api'})

var path = require('path'),
    request = require('request'),
    express = require('express'),
    app = express();

app.use(express.logger('dev'));
app.use(express.favicon());
app.use(express.bodyParser());
app.use(app.router);

module.exports = function (options) {
    var port = options.port || 8000,
        staticRoot = options.staticRoot || 'app',
        proxyUrl = options.proxyUrl || 'http://localhost',
        proxyPath = options.proxyBase + '/*';

    app.use(express.static(path.join(__dirname, staticRoot)));

    app.all(proxyPath, function (req, res) {
        req.url = proxyUrl + req.url;
        req.pipe(request(req.url)).pipe(res);                 
    });

    app.listen(port, function () {
        console.log('Now listening on port ' + port);
    });

    return app;
};