npm package: @martijnthe/nfc-pcsc
Description: Easy reading and writing NFC tags and cards
Author: Martin Endler
Latest version: 0.6.4

# nfc-pcsc

[![npm](https://img.shields.io/npm/v/nfc-pcsc.svg?maxAge=2592000)](https://www.npmjs.com/package/nfc-pcsc)
[![nfc-pcsc channel on discord](https://img.shields.io/badge/discord-join%20chat-61dafb.svg)](https://discord.gg/bg3yazg)

Easy **reading and writing NFC tags and cards** in Node.js

Built-in support for auto-reading **card UIDs** and reading tags emulated with [**Android HCE**](https://developer.android.com/guide/topics/connectivity/nfc/hce.html).

> **NOTE:** Reading tag UID and methods for writing and reading tag content **depend on NFC reader commands support**.
It is tested to work with **ACR122 USB reader** but it should work with **all PC/SC compliant devices**.  
When detecting tags does not work see [Alternative usage](#alternative-usage).

This library uses pcsclite native bindings [pokusew/node-pcsclite](https://github.com/pokusew/node-pcsclite) under the hood.

**Psst!** Problems upgrading to 0.6.0? Check out [this migration note](#migration-from-older-versions-to-060).


<!-- _**Psst!** You are browsing the documentation for the master branch, [look here](https://github.com/pokusew/nfc-pcsc/tree/v0.6.0) to see the usage of latest published version._ -->

## Content

<!-- START doctoc generated TOC please keep comment here to allow auto update -->
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->


- [Installation](#installation)
- [Flow of handling tags](#flow-of-handling-tags)
- [Basic usage](#basic-usage)
	- [Running examples locally](#running-examples-locally)
- [Alternative usage](#alternative-usage)
- [Reading and writing data](#reading-and-writing-data)
- [More examples](#more-examples)
- [FAQ](#faq)
  - [Migration from older versions to 0.6.0](#migration-from-older-versions-to-060)
  - [Can I use this library in my Electron app?](#can-i-use-this-library-in-my-electron-app)
  - [Can I use this library in my angular-electron app?](#can-i-use-this-library-in-my-angular-electron-app)
  - [Do I have to use Babel in my app too?](#do-i-have-to-use-babel-in-my-app-too)
  - [How do I require/import this library?](#how-do-i-requireimport-this-library)
  - [Can I read a NDEF formatted tag?](#can-i-read-a-ndef-formatted-tag)
- [Frequent errors](#frequent-errors)
  - [TypeError: NFC is not a constructor](#typeerror-nfc-is-not-a-constructor)
  - [Transaction failed error when using `CONNECT_MODE_DIRECT`](#transaction-failed-error-when-using-connect_mode_direct)
  - [Mifare Classic: Authentication Error after Multiple Writes](#mifare-classic-authentication-error-after-multiple-writes)
- [License](#license)

<!-- END doctoc generated TOC please keep comment here to allow auto update -->


## Installation

> **Requirements:** **Node.js 7+** (it might work under 6.x but it is not tested)

> **Note:** This library uses system PC/SC API. On **Windows and macOS** it works out of the box, but on Linux you have to do some steps as described [here](https://github.com/pokusew/node-pcsclite#installation)

Using npm:

```bash
npm install nfc-pcsc --save
```

or with yarn:

```bash
yarn add nfc-pcsc
```


## Flow of handling tags

When a NFC tag (card) is attached to the reader, the following is done:

1. it tries to find out the standard of card (`TAG_ISO_14443_3` or `TAG_ISO_14443_4`)

2. it will connect to the card, so any other card specific commands could be send

3. handling of card
	
	- when `autoProcessing` is true (default value) it will handle card by the standard:  
		
		`TAG_ISO_14443_3` *(Mifare Ultralight, 1K ...)*: sends GET_DATA command to retrieve **card UID**  
		`TAG_ISO_14443_4` *(e.g.: Andorid HCE)*: sends SELECT_APDU command to retrive data by file
		
		**then `card` event is fired, for which you can listen and then you can read or write data on the card**  
		see [Basic usage](#basic-usage) how to do it
		
	- when `autoProcessing` is false (default value) it will only fire `card` event  
	  then you can send whatever commands you want using `reader.transmit` method  
	  see [Alternative usage](#alternative-usage) how to do it
	  
4. you can read data, write data and send other commands


## Basic usage

> ### Running examples locally
> If you want see it in action, clone this repository, install dependencies with npm and run `npm run example`.
> ```bash
> git clone https://github.com/pokusew/nfc-pcsc.git
> npm install
> npm run example
> ```

You can use this library in any Node.js 7+ environment (even in an Electron app). 

```javascript
// in ES6
import { NFC } from 'nfc-pcsc';

// without Babel in ES2015
const { NFC } = require('nfc-pcsc');

const nfc = new NFC(); // optionally you can pass logger

nfc.on('reader', reader => {

	console.log(`${reader.reader.name}  device attached`);

	// needed for reading tags emulated with Android HCE
	// custom AID, change according to your Android for tag emulation
	// see https://developer.android.com/guide/topics/connectivity/nfc/hce.html
	reader.aid = 'F222222222';

	reader.on('card', card => {

		// card is object containing following data
		// [always] String type: TAG_ISO_14443_3 (standard nfc tags like Mifare) or TAG_ISO_14443_4 (Android HCE and others)
		// [always] String standard: same as type
		// [only TAG_ISO_14443_3] String uid: tag uid
		// [only TAG_ISO_14443_4] Buffer data: raw data from select APDU response

		console.log(`${reader.reader.name}  card detected`, card);

	});

	reader.on('card.off', card => {
		console.log(`${reader.reader.name}  card removed`, card);
	});

	reader.on('error', err => {
		console.log(`${reader.reader.name}  an error occurred`, err);
	});

	reader.on('end', () => {
		console.log(`${reader.reader.name}  device removed`);
	});

});

nfc.on('error', err => {
	console.log('an error occurred', err);
});
```


## Alternative usage

You can **disable auto processing of tags** and process them yourself.
It may be useful when you are using other than ACR122 USB reader or non-standard tags.

```javascript
// in ES6
import { NFC } from 'nfc-pcsc';

// without Babel in ES2015
const { NFC } = require('nfc-pcsc');

const nfc = new NFC(); // optionally you can pass logger

nfc.on('reader', reader => {

	// disable auto processing
	reader.autoProcessing = false;

	console.log(`${reader.reader.name}  device attached`);

	// needed for reading tags emulated with Android HCE
	// custom AID, change according to your Android for tag emulation
	// see https://developer.android.com/guide/topics/connectivity/nfc/hce.html
	// reader.aid = 'F222222222';

	reader.on('card', card => {

		// card is object containing following data
		// String standard: TAG_ISO_14443_3 (standard nfc tags like Mifare) or TAG_ISO_14443_4 (Android HCE and others)
		// String type: same as standard
		// Buffer atr

		console.log(`${reader.reader.name}  card inserted`, card);

		// you can use reader.transmit to send commands and retrieve data
		// see https://github.com/pokusew/nfc-pcsc/blob/master/src/Reader.js#L291

	});
	
	reader.on('card.off', card => {	
		console.log(`${reader.reader.name}  card removed`, card);
	});

	reader.on('error', err => {
		console.log(`${reader.reader.name}  an error occurred`, err);
	});

	reader.on('end', () => {
		console.log(`${reader.reader.name}  device removed`);
	});

});

nfc.on('error', err => {
	console.log('an error occurred', err);
});
```


## Reading and writing data

You can read from and write to numerous NFC tags including Mifare Ultralight (tested), Mifare Classic, Mifare DESFire, ...

> Actually, you can even read/write any possible non-standard NFC tag and card, via sending APDU commands according card's technical documentation via `reader.transmit`.

Here is **a simple example** showing reading and writing data to simple card **without authenticating** (e.g. Mifare Ultralight):  
_See [Basic usage](#basic-usage) how to set up reader or [look here for full code](/examples/from-readme-3.js)_

```javascript
reader.on('card', async card => {

	console.log();
	console.log(`card detected`, card);

	// example reading 12 bytes assuming containing text in utf8
	try {

		// reader.read(blockNumber, length, blockSize = 4, packetSize = 16)
		const data = await reader.read(4, 12); // starts reading in block 4, continues to 5 and 6 in order to read 12 bytes
		console.log(`data read`, data);
		const payload = data.toString(); // utf8 is default encoding
		console.log(`data converted`, payload);

	} catch (err) {
		console.error(`error when reading data`, err);
	}

	// example write 12 bytes containing text in utf8
	try {

		const data = Buffer.allocUnsafe(12);
		data.fill(0);
		const text = (new Date()).toTimeString();
		data.write(text); // if text is longer than 12 bytes, it will be cut off
		// reader.write(blockNumber, data, blockSize = 4)
		await reader.write(4, data); // starts writing in block 4, continues to 5 and 6 in order to write 12 bytes
		console.log(`data written`);

	} catch (err) {
		console.error(`error when writing data`, err);
	}

});
```

## More examples

📦📦📦 You can find more examples in [examples folder](/examples), including:

* [index.js](/examples/index.js) – detecting, authenticating, reading and writing cards (including instructions for Mifare Classic)
* [led.js](/examples/led.js) – controlling LED and buzzer of ACR122U look
* [desfire.js](/examples/desfire.js) – accessing and authenticating Mifare DESFire cards
* [uid-logger.js](/examples/uid-logger.js)

Feel free to open pull request, if you have any useful example, that you'd like to add. 

## FAQ

### Migration from older versions to 0.6.0

There was a **breaking change in 0.6.0**, as the default export was removed _(because of non-standard behaviour of ES6 modules in ES5 env (see [#12](https://github.com/pokusew/nfc-pcsc/issues/12) and [v0.6.0 release changelog](https://github.com/pokusew/nfc-pcsc/releases/tag/v0.6.0)))_.

You have to **update all requires or imports** of this library to the following _(note the brackets around NFC)_:
```javascript
// in ES6 environment
import { NFC } from 'nfc-pcsc';

// in ES2015 environment
const { NFC } = require('nfc-pcsc');
```

### Can I use this library in my [Electron](https://electron.atom.io/) app?

**Yes, you can!** It works well.

**But please note**, that this library uses [Node Native Modules](https://nodejs.org/api/addons.html) (underlying library [pokusew/node-pcsclite](https://github.com/pokusew/node-pcsclite) which provides access to PC/SC API).

Read carefully **[Using Native Node Modules](https://electron.atom.io/docs/tutorial/using-native-node-modules/) guide in Electron documentation** to fully understand the problematic.

**Note**, that because of Node Native Modules, you must build your app on target platform (you must run Windows build on Windows machine, etc.).  
You can use CI/CD server to build your app for certain platforms.  
For Windows, I recommend you to use [AppVeyor](https://appveyor.com/).  
For macOS and Linux build, there are plenty of services to choose from, for example [CircleCI](https://circleci.com/), [Travis CI](https://travis-ci.com/) [CodeShip](https://codeship.com/).

### Can I use this library in my [angular-electron](https://github.com/maximegris/angular-electron) app?

**Yes, you can!** But as this library uses Node Native Modules, you must change some config in `package.json` and `webpack.config.js` as described in [this comment](https://github.com/pokusew/nfc-pcsc/issues/24#issuecomment-327038188).

### Do I have to use Babel in my app too?

**No, you don't have to.** This library works great **in any Node.js 7+ environment** (even in an **Electron** app).

> Psst! Instead of using **async/await** (like in examples), you can use Promises.
> ```
> reader
>   .read(...)
>   .then(data => ...)
>   .catch(err => ...))
> ```

Internally it uses Babel under the hood to transpile things, that are not supported in Node.js v7 (e.g.: import/export). The transpiled code (in the dist folder) is then published into npm and when you install and require the library, it requires the transpiled code, so you don't have to worry about anything.

### How do I require/import this library?

```javascript
// in ES6 environment
import { NFC } from 'nfc-pcsc';

// in ES2015 environment
const { NFC } = require('nfc-pcsc');
```

If you want to import uncompiled source and transpile it yourself (not recommended), you can do it as follows:

```javascript
import { NFC } from 'nfc-pcsc/src';
```

### Can I read a NDEF formatted tag?

**Yes, you can!** You can read raw byte card data with `reader.read` method, and then you can parse it with any NDEF parser, e.g. [TapTrack/NdefJS](https://github.com/TapTrack/NdefJS).

**Psst!** There is also an example ([ndef.js](/examples/ndef.js)), but it is not finished yet. Feel free to contribute.


## Frequent errors

### TypeError: NFC is not a constructor

No worry, just check that you import/require the library like this _(note the brackets around NFC)_:
```javascript
// in ES6 environment
import { NFC } from 'nfc-pcsc';

// in ES2015 environment
const { NFC } = require('nfc-pcsc');
```

Take a a look at [How do I require/import this library?](#how-do-i-requireimport-this-library) section for more info.

> **Note**, that `const NFC = require('nfc-pcsc');` or `import NFC from 'nfc-pcsc'` (NFC without brackets) won't work, because there is no default export.  
It was removed for non-standard behaviour of ES6 modules in ES5 env (see [#12](https://github.com/pokusew/nfc-pcsc/issues/12) and [v0.6.0 release changelog](https://github.com/pokusew/nfc-pcsc/releases/tag/v0.6.0))

### Transaction failed error when using `CONNECT_MODE_DIRECT`

No worry, just needs a proper configuration, see [explanation and instructions here](https://github.com/pokusew/nfc-pcsc/issues/13#issuecomment-302482621).

### Mifare Classic: Authentication Error after Multiple Writes

No worry, you have probably modified a sector trailer instead of a data block, see [explanation and instructions here](https://github.com/pokusew/nfc-pcsc/issues/16#issuecomment-304989178).


## License

[MIT](/LICENSE.md)