Added examples on how to write or read NDEF messages using nfccard-tool

README.md

@@ -37,7 +37,7 @@ This library uses pscslite native bindings [pokusew/node-pcsclite](https://githu
   - [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)
+  - [How to read or write NDEF messages?](#how-to-read-or-write-ndef-messages)
 - [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)
@@ -332,12 +332,21 @@ If you want to import uncompiled source and transpile it yourself (not recommend
 import { NFC } from 'nfc-pcsc/src';
 ```
 
-### Can I read a NDEF formatted tag?
+### How to read or write NDEF messages?
 
-**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).
+**Yes, you can!** First install nfc-tools:
 
-**Psst!** There is also an example ([ndef.js](/examples/ndef.js)), but it is not finished yet. Feel free to contribute.
+```sh
+npm install nfc-tools --save
+```
+
+Then run the example:
+
+```sh
+npm run example-ndef
+```
 
+Read the doc at https://github.com/somq/nfccard-tool#nfccard-tool
 
 ## Frequent errors
 

examples/ndef.js

@@ -7,3 +7,120 @@
 
 import { NFC, TAG_ISO_14443_3, TAG_ISO_14443_4, KEY_TYPE_A, KEY_TYPE_B } from '../src/index';
 import pretty from './pretty';
+
+const nfcCard = require('nfccard-tool');
+
+
+const nfc = new NFC();
+
+nfc.on('reader', reader => {
+
+	console.log(`${reader.reader.name}  device attached`);
+
+  reader.on('card', async card => {
+
+	console.log(`card detected`, card);
+
+
+	/**
+	 * Write a card
+	 */
+
+    try {
+
+		/**
+		 *  1 - READ HEADER
+		 *  Read header: we need to verify if we have read and write permissions
+		 *               and if prepared message length can fit onto the tag.
+		 */
+		const cardHeader = await reader.read(0, 20);
+
+		const tag = nfcCard.parseInfo(cardHeader);
+
+		  /**
+		   * 2 - WRITE A NDEF MESSAGE AND ITS RECORDS
+		   */
+		  const message = [
+			{ type: 'text', text: 'I\'m a text message', language: 'en' },
+			{ type: 'uri', uri: 'https://github.com/somq/nfccard-tool' },
+			{ type: 'aar', packageName: 'com.github.nfccardtool' },
+		  ]
+
+		  // Prepare the buffer to write on the card
+		  const rawDataToWrite = nfcCard.prepareBytesToWrite(message);
+
+		  // Write the buffer on the card starting at block 4
+		  const preparationWrite = await reader.write(4, rawDataToWrite.preparedData);
+
+		  // Success !
+		  if (preparationWrite) {
+			console.log('Data have been written successfully.')
+		  }
+
+		} catch (err) {
+		console.error(`error when reading data`, err);
+		}
+
+
+		/**
+		 * Read a card
+		 */
+
+		try {
+
+			/**
+			 * READ MESSAGE AND ITS RECORDS
+			 */
+
+			/**
+			 *  1 - READ HEADER
+			 *  Read from block 0 to block 4 (20 bytes length) in order to parse tag information
+			 */
+			// Starts reading in block 0 until end of block 4
+			const cardHeader = await reader.read(0, 20);
+
+			const tag = nfcCard.parseInfo(cardHeader);
+			console.log('tag info:', JSON.stringify(tag));
+
+			/**
+			 *  2 - Read the NDEF message and parse it if it's supposed there is one
+			 */
+
+			// There might be a NDEF message and we are able to read the tag
+			if(nfcCard.isFormatedAsNDEF() && nfcCard.hasReadPermissions() && nfcCard.hasNDEFMessage()) {
+
+				// Read the appropriate length to get the NDEF message as buffer
+				const NDEFRawMessage = await reader.read(4, nfcCard.getNDEFMessageLengthToRead()); // starts reading in block 0 until 6
+
+				// Parse the buffer as a NDEF raw message
+				const NDEFMessage = nfcCard.parseNDEF(NDEFRawMessage);
+
+				console.log('NDEFMessage:', NDEFMessage);
+
+			} else {
+				console.log('Could not parse anything from this tag: \n The tag is either empty, locked, has a wrong NDEF format or is unreadable.')
+			}
+
+		} catch (err) {
+			console.error(`error when reading data`, err);
+		}
+
+	});
+
+	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);
+});