QR Code Protocol
The Goldshell hardware wallet uses QR codes for data exchange. Based on the UR protocol, a set of upper-layer protocols are designed for various scenarios and implemented in the SDK. This article will introduce how to use APIs to implement data encoding and decoding.
APIs
UREncoder
The UREncoder class encodes a UR object into the data of animated QR codes. The following code shows how to encode a EVM transaction:
import 'package:gs_ur_dart/gs_ur_dart.dart';
UR ur = GsWalletEthereumSDK.generateSignRequest(
uuid: "6c3633c0-02c0-4313-9cd7-e25f4f296729",
signData:
"337B718878426CA568BA103A5048A8D920945CE651C0A5360A79DA7E872E672D46C224866FEAF80F3D948682CCF31B683C1ACC29FA7D9BF6527BF627F545692A00",
dataType: EthDataType.typedTransaction,
path: "m/44'/60'/0'/0/0",
xfp: "F23F9FD2",
chainId: 1,
origin: "GsWallet");
final UREncoder urEncoder = UREncoder(ur);
String _currentQR = urEncoder.nextPart();
emit(_AnimatedQRDataState(_currentQR));
timer = Timer.periodic(const Duration(milliseconds: 250), (_) {
_currentQR = urEncoder.nextPart();
emit(_AnimatedQRDataState(_currentQR));
});
tip
In order to maintain a smooth QR code scanning speed, UREncoder will keep the generated QR code version to be lower than 15.
URDecoder
The URDecoder class decodes the animated QR codes and convert them into a UR object. The following code shows the process:
import 'package:gs_ur_dart/gs_ur_dart.dart';
final QRViewController controller；
controller.scannedDataStream.listen((event) {
URDecoder urDecoder = URDecoder();
urDecoder.receivePart(event.code); //event.code means page-data of a QR Code
double progress = urDecoder.getProgress();
if (urDecoder.isComplete()) {
final UR result = urDecoder.resultUR();
}
});
Examples
UREncoder
GS-UR-DART/example/animated_qr_code.dart.