Qtum Ethers

A module for using Qtum through an Ethers compliant library to make it simpler to use Qtum

Upgrading from 0.x.x => 1.x.x

TLDR: Breaking change in gas price, if you hardcode gas price then update your code otherwise you are probably ok upgrading to this version

This version has a breaking change in gas price Janus has a bug in eth_gasPrice that returns GWEI instead of WEI If you have hardcoded gas price in your code, you will need to update it from 0x9502f9000 to 0x5d21dba000 If you rely on eth_gasPrice then nothing else should be required

This release also works around the bug in Janus and will detect when it is fixed and act correctly The worst case scenario to not upgrading to this release is when the Janus server you talk to gets upgrade your transactions will have higher transaction fees as eth_gasPrice will return a larger number

Keep in mind that Qtum rejects transactions with absurdly high transaction fees, so the network will prevent accidental out of control spending by rejecting transactions - though this bug will not increase fees anywhere near that

We will be deploying bugfixed Janus to our mainnet server fleet

This release also improves transaction fee calculation and will result in lower transaction fees

Upgrading to this version will warn you when creating transactions with Janus instances that have not been upgraded after May 30th, 2022

After August 1st 2022, the warnings will turn into errors and you will be unable to create transactions with old Janus instances

Upgrading from 0.0.3 => 0.1.x

public key address generation now follows QTUM behavior, the same private keys will now generate different addresses

adds support for importing WIF private keys

gas price is now specified in WEI, not Satoshis

Installation

Open a console and run

npm install qtum-ethers-wrapper

Example

import {Contract} from "ethers"
import {
    QtumProvider as Provider,
    QtumWallet as Wallet,
    QtumContractFactory as ContractFactory,
    QTUM_BIP44_PATH, // Compatible with Qtum core wallet and electrum
    SLIP_BIP44_PATH  // Compatible with 3rd party wallets
} from "qtum-ethers-wrapper";
// point Qtum Provider at Janus node https://github.com/qtumproject/janus/
const mainnetProvider = new Provider("https://janus.qiswap.com/api/");
const testnetProvider = new Provider("https://testnet-janus.qiswap.com/api/");
// or deploy your own node locally with a regtest network
// see for a pre-built docker image https://hub.docker.com/r/ripply/janus
const regtestProvider = new Provider("http://localhost:23889");

const provider = testnetProvider;
// create a wallet
const privkey = "99dda7e1a59655c9e02de8592be3b914df7df320e72ce04ccf0427f9a366ec6e"
const signer = new Wallet(
    privkey,
    provider,
    {
        filterDust: true, // optional, will default to true in a future release
    }
)
// or create a random account and get the mnemonic
// const signer = Wallet.createRandom(/*{ path = SLIP_BIP44_PATH }*/}).connect(provider);
// const {locale, path, phrase} = signer._mnemonic();
// QRC20 ABI
const ABI = [{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"owner","type":"address"},{"indexed":true,"name":"spender","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"from","type":"address"},{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Transfer","type":"event"}];
// https://github.com/qtumproject/janus/blob/master/playground/pet-shop-tutorial/contracts/QRC20Token.sol
const BYTECODE = "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"
// QtumContractFactory is required to be used instead of standard ethers ContractFactory due to how contract addresses are computed differently
const simpleStore = new ContractFactory(ABI, BYTECODE, signer);

// simpleStore deployment example, returns address
async function deployToken() {
    const deployment = await simpleStore.deploy({
        gasLimit: "0x7a120", // 500,000
        gasPrice: "0x5d21dba000" // in WEI, not Satoshis
    });
    await deployment.deployed();
    return deployment.address
}
// connect to QRC20 token and interact with it 
async function transferToken(contractAddress, from, to, value) {
    const qrc20 = new Contract(contractAddress, QRC_ABI, signer)
    const name = await qrc20.transfer(from, to, value,
        {
            gasLimit: "0x62521", // 62521
            gasPrice: "0x5d21dba000", // in WEI, not Satoshis
        }
    );
}

const contractAddress = await deployToken();
await transferToken(contractAddress, "0x...", "0x...", 1);

Notes

• Issues

Qtum estimate gas function is not perfect so eth_estimateGas has a 20% buffer for gas limit

Janus doesn't return a transaction receipt for p2pkh tx's

This extension works with p2pk and p2pkh scripts only and asks Janus for p2pk and p2pkh scripts only