Express User Agent Redirect

Express UA Redirect is a simple configurable middleware for ExpressJS allowing you to redirect all routes to a configured route based on user agent restrictions. It was create to warn the user that the browser is not compatible, but it can be used for other reasons.

Here is an example to redirect IE 8 and less user to /incompatible-browser route:

app.use(uaRedirect({
  browsers: {
    unauthorized: {
      IE: '8-'
    }
  },
  redirectTo: '/incompatible-browser'
}));

There is also an evergreen mode to accept all automatic updated browsers and redirect all other:

app.use(uaRedirect({
  browsers: {
    evergreen: true
  },
  redirectTo: '/incompatible-browser'
}));

Installation

Install the dependency

npm install --save express-ua-redirect

Install it on your express server

var uaRedirect = require('express-ua-redirect');
//...
app.use(uaRedirect(options));

How to use

1. Proceed to installation has describe before
2. Configure the browsers option
3. Add a route to your server according to the option redirectTo
4. Make what you will with this route
5. You're done!

Exemple

To redirect IE7 to /update-your-browser who it render update-your-browser.ejs template.

server.js

var express = require('express');
var uaRedirect = require('express-ua-redirect');

var app = express();
app.set('view engine', 'ejs');

// Configure uaRedirect
app.use(uaRedirect({
  browsers: {
    unauthorized: {
      IE: 7
    }
  },
  redirectTo: '/update-your-browser'
}));

// ...
// Define your routes
// ...

// Define the associate route to `redirectTo` option
app.get('/update-your-browser', function(req, res) {
  res.render('update-your-browser');
});

update-your-browser.ejs

<h1>Oups your browser is not compatible</h1>
<p>We recommend that you update your browser ...</p>

options

• browsers {Object}
  • unauthorized {Object} Specify unauthorized browser(s) and its version with a browser object described below
  • authorized {Object} Specify authorized browser(s) and its version with a browser object described below
  • evergreen {Boolean} Redirect all not evergreen browser
• redirectTo {String} Route path

Browser object possibilities

{
  IE: 8,         // match the exact version of IE8
  Chrome: '44+', // match chrome 44 and above
  Safari: '8-'   // match safari 8 and below
}

Browser name is not case sensitive an you can use all browser listed on ua-parser-js plugin documentation here

Version condition can be String or Number. With + or - indicator it must be a String.

Priority order

If you specify an unauthorized browser it will override authorized browser and authorized override evergreen browsers.

unauthorized > authorized > evergreen

Use cases

Lock IE8 and below

app.use(uaRedirect({
  browsers: {
    unauthorized: {
      IE: '8-'
    }
  },
  redirectTo: '/incompatible-browser'
}));

Authorized modern browsers

app.use(uaRedirect({
  browsers: {
    authorized: {
      safari: '7+',
      IE: '9+'
    },
    evergreen: true
  },
  redirectTo: '/incompatible-browser'
}));