Hardhat Conflux Plugin

Hardhat is an exceptional tool for building smart contracts. It serves as a development environment, testing framework, and asset pipeline for Ethereum-like blockchains, such as Conflux. The Hardhat Conflux Plugin adds Conflux Core Space support to Hardhat.

Developers can use Hardhat to compile Solidity code and the Hardhat-Conflux plugin to deploy, interact with, and test contracts on Core Space.

The Hardhat-Conflux plugin is built on top of js-conflux-sdk, making its usage for deployment and interaction very similar to that of js-conflux-sdk.

If you are not familiar with Hardhat, please refer to the Hardhat documentation.

Installation

After installing Hardhat, you can install the plugin with:

npm install hardhat-conflux js-conflux-sdk

Configuration

First, import the plugin in your hardhat.config.js:

require("hardhat-conflux");

Or in hardhat.config.ts:

import "hardhat-conflux";

Then, add the Conflux network to your hardhat.config.js:

const PRIVATE_KEY = "0x0123456789012345678901234567890123456789012345678901234567890123"; // replace with your private key
module.exports = {
    defaultNetwork: "cfxTestnet",
    networks: {
        cfx: {
            url: "https://main.confluxrpc.com",
            accounts: [PRIVATE_KEY],
            chainId: 1029,
        },
        cfxTestnet: {
            url: "https://test.confluxrpc.com",
            accounts: [PRIVATE_KEY],
            chainId: 1,
        },
    }
}

If your configuration file is hardhat.config.ts, the settings are similar.

Ensure that the private key's account you use has enough balance to interact with Core Space. If not, you can use the faucet to obtain some test tokens.

What the Hardhat-Conflux Plugin Provides

Tasks

This plugin provides the verifyCfxContract task, which allows you to verify contracts through ConfluxScan's service.

npx hardhat verifyCfxContract Greeter cfxtest:acba7cvb1k6bhctzsfshybg5zgch39gnpuc8teem53

Environment Extensions

This plugin extends the Hardhat Runtime Environment by adding the following members:

ConfluxSDK

This is the js-conflux-sdk object, which is the same as the one obtained by require('js-conflux-sdk').

conflux object

A Conflux field is added to the Hardhat Runtime Environment, which is a Conflux instance automatically connected to the selected network, with extra Hardhat-specific functionality.

// Get a signer array
function getSigners(): Promise<ConfluxSDK.PrivateKeyAccount[]>;
// Get js-conflux-sdk Contract Factory by name
function getContractFactory(name: string): Promise<ConfluxSDK.Contract>;
// Get js-conflux-sdk Contract Factory by ABI and bytecode
function getContractFactory(abi: any[], bytecode: string): Promise<ConfluxSDK.Contract>;
// Get js-conflux-sdk Contract instance by name and address
function getContractAt(name: string, address: string): Promise<ConfluxSDK.Contract>;
// Get js-conflux-sdk Contract instance by ABI and address
function getContractAt(abi: any[], address: string): Promise<ConfluxSDK.Contract>;

Usage

Developers can write Hardhat scripts to deploy, interact with, and test contracts on Core Space.

Deploy Contract

Here is a simple example of deploying a contract:

async function main() {
    const signers = await hre.conflux.getSigners();
    const defaultAccount = signers[0];

    // Deploy the contract
    const Greeter = await hre.conflux.getContractFactory('Greeter');
    const receipt = await Greeter.constructor('Hello').sendTransaction({
        from: defaultAccount.address,
    }).executed();

    console.log(`Contract deployment ${receipt.outcomeStatus === 0 ? 'succeeded' : 'failed'}`);
    
    if (receipt.outcomeStatus !== 0) {
        console.log(`Error message: ${receipt.outcomeErr}`);
        return;
    }

    const contractAddress = receipt.contractCreated;

    console.log(`Newly deployed contract address: ${contractAddress}`);
}

main().catch(err => {
    console.log(err);
    process.exit(1);
});

Then, you can run this script with:

npx hardhat run scripts/deploy.js --network cfxTestnet

After executing the script, you can view the contract address in the console.

Interact with Contract

Here is a simple example of interacting with a contract:

async function main() {
    const signers = await hre.conflux.getSigners();
    const defaultAccount = signers[0];
    const contractAddress = 'cfxtest:acba7cvb1k6bhctzsfshybg5zgch39gnpuc8teem53'; // replace with your contract address
    
    // Get the contract instance
    const greeter = await hre.conflux.getContractAt('Greeter', contractAddress);
    
    // Read the contract state
    const greet = await greeter.greet();
    
    // Update the contract state by sending a transaction
    const receipt = await greeter.setGreeting('new greet').sendTransaction({
        from: defaultAccount.address,
    }).executed();
    console.log('Update contract state transaction hash: ', receipt.transactionHash);
}

main().catch(err => {
    console.log(err);
    process.exit(1);
});

Then, you can run this script with:

npx hardhat run scripts/interact.js --network cfxTestnet

Verify Contract

Use the verifyCfxContract task to verify contracts through ConfluxScan's service.

npx hardhat verifyCfxContract Greeter cfxtest:acba7cvb1k6bhctzsfshybg5zgch39gnpuc8teem53

Complete Example

A complete example is available at hardhat-conflux-example.

FAQs

Can I use the Hardhat network to test contracts for Conflux Core?

If your contracts do not use any Conflux-specific features (like Internal Contracts, 1820, create2), you can use the Hardhat network to test your contracts. For the VM differences between the Hardhat network and Conflux Core, please refer to VM differences.

Can I use the Hardhat fork feature on Conflux Core?

No. The Hardhat fork feature is not supported on Conflux Core.

When I use helper methods in TypeScript, it shows an error like Property 'getContractFactory' does not exist on 'hre.conflux'

Currently, this plugin does not provide TypeScript type definitions. You can use // @ts-ignore to suppress the error message; it will not affect the code's execution. We plan to provide TypeScript type definitions in the future.