devicize

devicize is a node.js package that analyses the user agent of the browser and gives information about device type (desktop, tablet or phone).

Using sessions

If you are using express-session middleware, the information about device is stored as a session variable to avoid re-analyzing the user agent and lose precious machine cycles, which make it suitable for big multi-device applications.

var expressSession = require('express-session');

app.use( expressSession({secret:'mySecretKey', cookie: { maxAge: 60000 }, resave:false, saveUninitialized:true}) );

The devicize package can be used in many ways, listed below.

Simple syntax

The simplest way to use it is to get a different string depending on the device type. For example:

app.get( '/size', showDeviceSize );

function showDeviceSize(req,res){
  console.log("Devicize : " , require("devicize")(req , { "M":"mobile/" , "T":"tablet/" , "P":"phone/" }));
}

When no strings specified, default information given is 1 letter:

• D : Desktop
• T : Tablet
• P : Phone

Promise syntax

Another possibility is a promise-like syntax :

require("devicize")(req , { "promise" : true } ).phone( itsPhone ).tablet( itsTablet ).desktop( itsDesktop );
require("devicize")(req , { "promise" : true } ).desktop( itsDesktop ).otherwise( itsNotDesktop );

Middleware

The most interesting use of the package is as a middleware to serve different files depending on the device type:

function renderJade(req, res, filename){
    filename = filename.slice(0,-4)+".jade";
    require("jade").renderFile(filename , function(err,html){if (err) {res.send(500);} else {res.send(200,html);}});
}

function page404(req, res, filename){
    res.send(404);
}

app.use( "/pub", devicize.static( __dirname+"/public/",{
     ".htm":renderJade,
     ".jade":page404
    }) );

The code above permits to serve static files fom different directories when url starting with /pub/... : files are served from /public/desktop/, /public/tablet/ and /public/phone/.

In addition, the url with .htm extension is served from a .jade compiled file and .jade files are excluded from visualisation.