KHQR Generator for Dart #

A Dart library for generating and parsing KHQR codes, based on the Bakong KHQR specification and inspired by the bakong-khqr npm package.

Disclaimer: This library is an independent implementation and is not an official product of the National Bank of Cambodia (NBC) or the Bakong system.

Features #

• Generate KHQR codes for individual and merchant accounts.
• Support for static and dynamic QR codes.
• Verify the validity of KHQR codes.
• Decode KHQR codes to extract the embedded information.
• No external dependencies for core functionality.

Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  khqr_generator: latest_version

Then, run flutter pub get to install the package.

Usage #

Import the library in your Dart file:

import 'package:khqr_generator/khqr_generator.dart';

Generating an Individual QR Code #

To generate a QR code for an individual, use the BakongKHQR.generateIndividual method. You need to provide an IndividualInfo object with the required information.

Example: Static QR Code

final individualInfo = IndividualInfo(
  bakongAccountID: 'test@test',
  merchantName: 'Test Merchant',
  merchantCity: 'Phnom Penh',
);

final response = BakongKHQR.generateIndividual(individualInfo);

if (response.status.code == 0) {
  print('QR Code: ${response.data!.qr}');
  print('MD5: ${response.data!.md5}');
} else {
  print('Error: ${response.status.message}');
}

Example: Dynamic QR Code (with amount)

final individualInfo = IndividualInfo(
  bakongAccountID: 'test@test',
  merchantName: 'Test Merchant',
  merchantCity: 'Phnom Penh',
  amount: 100.0,
  currency: KHQRCurrency.usd.code,
  expirationTimestamp: DateTime.now().millisecondsSinceEpoch + 3600000, // 1 hour from now
);

final response = BakongKHQR.generateIndividual(individualInfo);

if (response.status.code == 0) {
  print('QR Code: ${response.data!.qr}');
} else {
  print('Error: ${response.status.message}');
}

Generating a Merchant QR Code #

To generate a QR code for a merchant, use the BakongKHQR.generateMerchant method with a MerchantInfo object.

final merchantInfo = MerchantInfo(
  bakongAccountID: 'test@test',
  merchantName: 'Test Merchant',
  merchantCity: 'Phnom Penh',
  merchantID: '1234567890',
  acquiringBank: 'Test Bank',
);

final response = BakongKHQR.generateMerchant(merchantInfo);

if (response.status.code == 0) {
  print('QR Code: ${response.data!.qr}');
} else {
  print('Error: ${response.status.message}');
}

Verifying a KHQR Code #

You can verify the integrity of a KHQR code using the BakongKHQR.verify method. This checks the CRC and format of the QR string.

String qrCode = '...'; // The KHQR string
final result = BakongKHQR.verify(qrCode);

if (result.isValid) {
  print('QR Code is valid.');
} else {
  print('QR Code is invalid.');
}

Decoding a KHQR Code #

To decode a KHQR code and extract the embedded information, use the BakongKHQR.decode method.

String qrCode = '...'; // The KHQR string
final response = BakongKHQR.decode(qrCode);

if (response.status.code == 0) {
  final decodedData = response.data!.decodedData;
  print('Decoded Data: $decodedData');
} else {
  print('Error: ${response.status.message}');
}

API Reference #

BakongKHQR #

This class contains the main methods for generating, verifying, and decoding KHQR codes.

• static KHQRResponse generateIndividual(IndividualInfo info)
• static KHQRResponse generateMerchant(MerchantInfo info)
• static VerificationResult verify(String qr)
• static KHQRResponse decode(String qr)

IndividualInfo #

This class holds the information for an individual QR code.

MerchantInfo #

This class extends IndividualInfo and adds merchant-specific fields.

KHQRCurrency #

An enum representing the supported currencies.

• KHQRCurrency.khr (code: 116)
• KHQRCurrency.usd (code: 840)

Error Handling #

The library returns a KHQRResponse object which contains a status field. If status.code is 0, the operation was successful. Otherwise, it contains an error code and message.

You can find the list of error codes in the ErrorCode class.

final response = BakongKHQR.generateIndividual(...);

if (response.status.code != 0) {
  print('Error Code: ${response.status.errorCode}');
  print('Error Message: ${response.status.message}');
}