Multi-language routes in express.js?

Question

I\'m wondering if there is a best practise example on how to implement multi-lanuage routes in express.js. i want to use the accept-language header to get the b

Answer 1

Middleware recommendation

The answer by @miro is very good but can be improved as in the following middleware in a separate file (as @ebohlman suggests).

The middleware

module.exports = {
  configure: function(app, i18n, config) {
    app.locals.i18n = config;
    i18n.configure(config);
  },
  init: function(req, res, next) {
    var rxLocale = /^\/(\w\w)/i;
    if (rxLocale.test(req.url)){
      var locale = rxLocale.exec(req.url)[1];
      if (req.app.locals.i18n.locales.indexOf(locale) >= 0)
        req.setLocale(locale);
    }
    //else // no need to set the already default
    next();
  },
  url: function(app, url) {
    var locales = app.locals.i18n.locales;
    var urls = [];
    for (var i = 0; i < locales.length; i++)
      urls[i] = '/' + locales[i] + url;
    urls[i] = url;
    return urls;
  }
};

Also in sample project in github.

Explanation

The middleware has three functions. The first is a small helper that configures i18n-node and also saves the settings in app.locals (haven't figured out how to access the settings from i18n-node itself).

The main one is the second, which takes the locale from the url and sets it in the request object.

The last one is a helper which, for a given url, returns an array with all possible locales. Eg calling it with '/about' we would get ['/en/about', ..., '/about'].

How to use

In app.js:

// include
var i18n = require('i18n');
var services = require('./services');

// configure
services.i18nUrls.configure(app, i18n, {
  locales: ['el', 'en'],
  defaultLocale: 'el'
});

// add middleware after static
app.use(services.i18nUrls.init);

// router
app.use(services.i18nUrls.url(app, '/'), routes);

Github link

The locale can be accessed from eg any controller with i18n-node's req.getLocale().

RFC

What @josh3736 recommends is surely compliant with RFC etc. Nevertheless, this is a quite common requirement for many i18n web sites and apps, and even Google respects same resources localised and served under different urls (can verify this in webmaster tools). What I would recommended though is to have the same alias after the lang code, eg /en/home, /de/home etc.