server-side browser detection? node.js

I threw this together using ua-parser-js. I'm sure it can be improved but it's functional.

Install the package:

sudo npm install ua-parser-js

In your routes file require UAParser:

var UAParser = require('ua-parser-js');

Do some stuff with it:

function ensureLatestBrowser(req, res, next) {
  var parser = new UAParser();
  var ua = req.headers['user-agent'];
  var browserName = parser.setUA(ua).getBrowser().name;
  var fullBrowserVersion = parser.setUA(ua).getBrowser().version;
  var browserVersion = fullBrowserVersion.split(".",1).toString();
  var browserVersionNumber = Number(browserVersion);

  if (browserName == 'IE' && browserVersion <= 9)
    res.redirect('/update/');
  else if (browserName == 'Firefox' && browserVersion <= 24)
    res.redirect('/update/');
  else if (browserName == 'Chrome' && browserVersion <= 29)
    res.redirect('/update/');
  else if (browserName == 'Canary' && browserVersion <= 32)
    res.redirect('/update/');
  else if (browserName == 'Safari' && browserVersion <= 5)
    res.redirect('/update/');
  else if (browserName == 'Opera' && browserVersion <= 16)
    res.redirect('/update/');
  else
    return next();
}

and then in your route just call:

app.all(/^(?!(\/update)).*$/, ensureLatestBrowser);

If you want to see what other information you can get with UAParser check out their demo page.

The ua-parser library for node (npm install ua-parser) exposes a big set of regexes for browser user-agent strings. I'd strongly recommend it for your needs.

I wanted to do a simple redirection to a mobile version of my site, so user-agent is reliable enough. I wanted to do it server-side so I didn't waste time loading unnecessary css and js on the client. http://detectmobilebrowsers.com/ had the most robust regex to match. So I threw together some express middleware that will let you do the redirection by just adding two lines of code to your app.

npm install detectmobilebrowsers to install

express = require 'express'
mobile  = require 'detectmobilebrowsers'

app = express()
app.configure () ->
  app.use mobile.redirect 'http://m.domain.com'
app.get '/', (req, res) ->
  res.send 'Not on Mobile'
app.listen 3000

var ua = request.headers['user-agent'],
    $ = {};

if (/mobile/i.test(ua))
    $.Mobile = true;

if (/like Mac OS X/.test(ua)) {
    $.iOS = /CPU( iPhone)? OS ([0-9\._]+) like Mac OS X/.exec(ua)[2].replace(/_/g, '.');
    $.iPhone = /iPhone/.test(ua);
    $.iPad = /iPad/.test(ua);
}

if (/Android/.test(ua))
    $.Android = /Android ([0-9\.]+)[\);]/.exec(ua)[1];

if (/webOS\//.test(ua))
    $.webOS = /webOS\/([0-9\.]+)[\);]/.exec(ua)[1];

if (/(Intel|PPC) Mac OS X/.test(ua))
    $.Mac = /(Intel|PPC) Mac OS X ?([0-9\._]*)[\)\;]/.exec(ua)[2].replace(/_/g, '.') || true;

if (/Windows NT/.test(ua))
    $.Windows = /Windows NT ([0-9\._]+)[\);]/.exec(ua)[1];

That should work for you. Just put it in your response handler.