qr-image

QR code is this super cool thing you probably have been seeing all over the place lately. It started appearing in North America a few years ago but the actual standard is close to two decades old. It allows you to embed any small amount of data that could be decoded with a basic camera equipped phone. Most common use case here is embedding URLs in printed adverising so that those who are interested could simply point their phone at the add and go to the site instead of having to type in URLs.

qr-image (Github: alexeyten/qr-image, License: MIT) is a module by Alexey Ten to render QR code with node.js and no external dependencies.

npm install qr-image

Overview

• No dependecies. This is a really cool bit, if you look at package.json there are literally no dependencies there.
• Generate image in png, svg, eps and pdf formats.
• Support UTF-8.

Usage

var qr = require('qr-image');
var fs = require('fs');

var code = qr.image('http://blog.nodejitsu.com', { type: 'svg' });
var output = fs.createWriteStream('nodejitsu.svg')

code.pipe(output);

Because we are dealing with streams here, hooking this up to HTTP server is super easy.

var qr = require('qr-image');
var express = require('express');

var app = express();

app.get('/', function(req, res) {
  var code = qr.image(new Date().toString(), { type: 'svg' });
  res.type('svg');
  code.pipe(res);
});

app.listen(3000);

Now, going to http://localhost:3000 will spit out a QR code with current time. Wicked!

Metadata

QR code allows you embed pretty much any text, but with some additional formatting you can tell scanning applications about the data and what you want them to do with it. Here are a few most common formats: