text:     
      var Canvas = require('canvas')
        , Image = Canvas.Image
        , qrcode = require('jsqrcode')(Canvas)
   
      var filename = __dirname + '/qrcode.png'
   
      var image = new Image()
      image.onload = function(){
        var result;
        try{
          result = qrcode.decode(image);
          console.log('result of qr code: ' + result);
        }catch(e){
          console.log('unable to read qr code');
        }
      }
      image.src = filename