Wednesday, September 24, 2014

PCSC sample in JavaScript (Node.js)

To continue the list of PC/SC wrappers initiated more than four years ago with "PC/SC sample in different languages" I now present a PC/SC sample written in JavaScript using Node.js.

node-pcsclite project

The node-pcsclite project is hosted at github and is quiet active. Support of Windows is not yet available. Support of Mac OS X is now correct after I proposed some patches.

The installation on a Debian unstable or testing (Jessie) system is easy. Just follow the project documentation. Debian stable (Whezzy) do not have the nodejs packages but these packages are available in wheezy-backports.

One potential problem is that the Node.js binary is called nodejs on Debian to avoid a conflict with another node binary. To have a node binary corresponding to Node.js you need to install the Debian package nodejs-legacy. It is not difficult but may be the source of some difficulties at the beginning.

PC/SC accesses from node-pcsclite

The wrapper provides access the following PC/SC functions:
  • connect
  • disconnect
  • transmit
  • control

A reader event (reader removed) is reported as an event.

The card status change is reported as an event.

The reconnect function is missing. A bug #10 is open requesting its addition.

Sample source code

#!/usr/bin/env node

var pcsc = require('./lib/pcsclite');

var pcsc = pcsc();

pcsc.on('reader', function(reader) {

    function exit() {

    cmd_select = new Buffer([0x00, 0xA4, 0x04, 0x00, 0x0A, 0xA0, 0x00, 0x00, 0x00, 0x62, 0x03, 0x01, 0x0C, 0x06, 0x01]);
    cmd_command = new Buffer([0x00, 0x00, 0x00, 0x00]);


    reader.connect(function(err, protocol) {
        if (err) {
            return exit();
        reader.transmit(cmd_select, 255, protocol, function(err, data) {
            if (err) {
                return exit();
            console.log('Data received', data);
            reader.transmit(cmd_command, 255, protocol, function(err, data) {
                if (err) {
                } else {
                    console.log('Data received', data);
                    console.log('Data received', data.toString());
                return exit();

pcsc.on('error', function(err) {
    console.log('PCSC error', err.message);


Node.js is an asynchronous framework. So a typical Node.js design pattern is to use a call-back instead of blocking the execution of a function.

The code can be complex to follow since you have a cascade of call-backs if you need to send a sequence of APDU. In the sample we only need to send 2 consecutive APDU.

The program is not sequential but event based. So without the explicit exit after 1 second the program never terminates and you need to stop it using Control-C. It is strange for me.


Using: Gemalto PC Twin Reader 00 00
Data received <SlowBuffer 90 00>
Data received <SlowBuffer 48 65 6c 6c 6f 20 77 6f 72 6c 64 21 90 00>
Data received Hello world!�

Similar projects

Two other similar projects are also found at github. They have both the same name node-pcsc but are not the same project:

coolbong node-pcsc

The node-pcsc interface from coolbong uses a synchronous API so no call-back are involved for PC/SC calls. You can send a sequence of APDU as you would do in C.

This wrapper is for Windows only and need some work to port it to Unix. I opened a bug #1 requesting Unix support.

jokesterfr node-pcsc

This wrapper is not yet able to send arbitrary APDU to a card. It looks like a work in progress that stopped in November 2013.


If you want to use a smart card from a JavaScript program using Node.js the best choice may be the node-pcsclite project. The project maintainer is nice and reactive.

If you know a PC/SC wrapper that is not yet in my list then please contact me.

Edit, October 3rd 2014

After discussing with Santiago Gimeno (node-pcsclite author) and fixing Mac OS X bugs in node-pcsclite I modified the sample source code to add the clean up exit() function and exit properly from the program when no more callbacks are waiting.