khqr_generator 0.0.1

KHQR Generator (It's not an official library from NBC)

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.

Parameter	Type	Required	Description
bakongAccountID	String	Yes	The Bakong account ID.
merchantName	String	Yes	The name of the merchant or individual.
merchantCity	String	Yes	The city of the merchant or individual.
amount	double	No	The transaction amount. If provided, the QR becomes dynamic.
currency	int	No	The transaction currency code (from KHQRCurrency). Defaults to KHR.
expirationTimestamp	int	No	The expiration timestamp for dynamic QR codes (in milliseconds since epoch).
billNumber	String	No	The bill number for the transaction.
mobileNumber	String	No	The mobile number associated with the transaction.
storeLabel	String	No	The label for the store.
terminalLabel	String	No	The label for the terminal.
purposeOfTransaction	String	No	The purpose of the transaction.

MerchantInfo

This class extends IndividualInfo and adds merchant-specific fields.

Parameter	Type	Required	Description
merchantID	String	Yes	The ID of the merchant.
acquiringBank	String	Yes	The acquiring bank for the merchant.

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}');
}