Express 4 middleware to add req.countryCode, which is the ISO alpha 2 country code for a request.
In app.js
var expressGeoIP = require('express-geoip');
app.use(expressGeoIP('US').getCountryCodeMiddleware);
Then, in your routes, check req.countryCode for the looked up country code.
1.2.0 - Added tests, new function signature
1.0.0 - Initial release