README.md

A library to interface with the Witnet Protocol. For more information about Witnet visit witnet.io

Usage

A simple usage example:

import 'package:witnet/node.dart' show NodeClient, SyncStatus;

String nodeIp = '127.0.0.1';
int nodePort = 21338;

main() async{
  print('Connecting to Node at $nodeIp:$nodePort...');
  NodeClient nodeClient = NodeClient(address: nodeIp, port: nodePort);
  SyncStatus syncStatus = await nodeClient.syncStatus();
  if (syncStatus.nodeState == 'Synced'){
    print('Node is synced. Current Epoch ${syncStatus.currentEpoch}');
  } else {
    print('Node is not synced. Current State: [${syncStatus.nodeState}]');
    print('Current Epoch:   [${syncStatus.currentEpoch}]');
    print('Last checkpoint: [${syncStatus.chainBeacon.checkpoint}]');
    print('${(syncStatus.chainBeacon.checkpoint / syncStatus.currentEpoch) * 100} % synced.');
  }
}

Recover Keys

import 'package:witnet/witnet.dart' show WitPrivateKey, Xprv;

void recoverKeys(){
  String xprvStr = 'xprv1qpujxsyd4hfu0dtwa524vac84e09mjsgnh5h9crl8wrqg58z5wmsuqqcxlqmar3fjhkprndzkpnp2xlze76g4hu7g7c4r4r2m2e6y8xlvu566tn6';
  String mnemonic = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about';
  Xprv nodeXprv = Xprv.fromXprv(xprvStr);
  WitPrivateKey nodeKey = nodeXprv.privateKey;
  print('Node Address: ${nodeXprv.address.address}');
  Xprv walletMasterKey = Xprv.fromMnemonic(mnemonic: mnemonic);
  Xprv walletExternalKeychain = walletMasterKey / 3.0 / 4919.0 / 0.0 / 0;
  Xprv walletInternalKeychain = walletMasterKey / 3.0 / 4919.0 / 0.0 / 1;

  for(int i=0; i < 10; i++){
    Xprv external = walletExternalKeychain / i;
    Xprv internal = walletInternalKeychain / i;
    print('${external.path} ${external.address.address}');
    print('${internal.path} ${internal.address.address}');
  }
}

Create a signed VTTransaction from UTXO data.

import 'package:witnet/data_structures.dart' show UtxoSelectionStrategy;
import 'package:witnet/node.dart' show NodeClient, SyncStatus;
import 'package:witnet/schema.dart' show VTTransaction, ValueTransferOutput;
import 'package:witnet/witnet.dart' show Address, Xprv, nanoWitToWit, signMessage, verify;

List<ValueTransferOutput> outputs = [
  ValueTransferOutput.fromJson({'pkh': 'wit174la8pevl74hczcpfepgmt036zkmjen4hu8zzs', 'time_lock': 0, 'value': 1000000000,}),
];
String testXprvStr = 'xprv1qpujxsyd4hfu0dtwa524vac84e09mjsgnh5h9crl8wrqg58z5wmsuqqcxlqmar3fjhkprndzkpnp2xlze76g4hu7g7c4r4r2m2e6y8xlvu566tn6';
String testMnemonic = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about';
String nodeIp = '127.0.0.1';
int nodePort = 21338;


main() async {
  print('Connecting to Node at $nodeIp:$nodePort...');
  NodeClient nodeClient = NodeClient(address: nodeIp, port: nodePort);
  SyncStatus syncStatus = await nodeClient.syncStatus();
  if (syncStatus.nodeState == 'Synced') {
    Xprv nodeXprv = Xprv.fromXprv(testXprvStr);
    Address address = nodeXprv.address;
    await address.getUtxoInfo(source: nodeClient);
    print('${address.address}');
    print('${address.balanceWit} WIT');
    VTTransaction transaction = address.createVTT(
        outputs: outputs,
        privateKey: nodeXprv.privateKey,
        utxoStrategy: UtxoSelectionStrategy.SmallFirst,
        fee: 1,
        networkSource: nodeClient);
    print(transaction.jsonMap);
    print(transaction.body.toRawJson());
    print(transaction.transactionID);
  }
}

Create a KeyedSignature from a Transaction hash with a Private Key.

import 'dart:typed_data';

import 'package:witnet/witnet.dart' show WitPrivateKey;
import 'package:witnet/schema.dart' show KeyedSignature, PublicKey, Secp256k1Signature, Signature;
KeyedSignature signHash(String hash, WitPrivateKey privateKey){
  final sig = privateKey.signature(hash);
  int compressed = privateKey.publicKey.encode().elementAt(0);
  Uint8List key_bytes = privateKey.publicKey.encode().sublist(1);
  return KeyedSignature(
    publicKey: PublicKey(bytes: key_bytes),
    signature: Signature(secp256k1: Secp256k1Signature(der: sig.encode())),
  );
}

Build a VTTransaction from inputs and outputs.

import 'package:witnet/witnet.dart' show WitPrivateKey;
import 'package:witnet/schema.dart' show VTTransaction, Input, ValueTransferOutput, VTTransactionBody;
List<Input> inputs = [
  Input.fromJson({'output_pointer':'0000000000000000000000000000000000000000000000000000000000000000:1'}),
];
List<ValueTransferOutput> outputs = [
  ValueTransferOutput.fromJson({'pkh': 'wit174la8pevl74hczcpfepgmt036zkmjen4hu8zzs', 'time_lock': 0, 'value': 1000000000,}),
];
Future<VTTransaction> basicTransaction({
  required List<Input> inputs,
  required List<ValueTransferOutput> outputs,
  required WitPrivateKey privateKey
}) async {
  VTTransactionBody body = VTTransactionBody(inputs: inputs, outputs: outputs);
  VTTransaction transaction = VTTransaction(body: body, signatures: []);
  return transaction;
}

Send a transaction.

import 'package:witnet/node.dart';
import 'package:witnet/schema.dart' show VTTransaction, VTTransactionBody;

String nodeIp = '127.0.0.1';
int nodePort = 21338;

main() async {
  NodeClient nodeClient = NodeClient(address: nodeIp, port: nodePort);
  SyncStatus syncStatus = await nodeClient.syncStatus();
  if (syncStatus.nodeState == 'Synced') {
    // an empty transaction
    VTTransactionBody body = VTTransactionBody(inputs: [], outputs: []);
    VTTransaction transaction = VTTransaction(body: body, signatures: []);
    String transactionID = transaction.transactionID;
    // change to true if you really want to send the transaction
    var resp = await nodeClient.inventory({'transaction': transaction.jsonMap});
    print(resp);
  }
}

Features and bugs

Please file feature requests and bugs at the issue tracker.

Created by the Witnet Community and released under the GNU General Public License v3.0

Acknowledgment

We would like to express our sincere gratitude to @parody_bit for generously creating and sharing this library for the improvement of the Witnet ecosystem. Thank you for your hard work and dedication.