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Hello Smart Contract with web3.js

When developing a smart contract with web3.js on Artela, which is compatible with the Ethereum Virtual Machine (EVM), the typical workflow involves creating the smart contract in Solidity, compiling it, deploying it to the Artela blockchain, and then interacting with it using web3.js. Below is a straightforward example:

Pre-requisites:

1. Create a Smart Contract​

Create your smart contract source files with a .sol extension. For example, create a hello.sol file:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.8.12 <0.9.0;

contract Hello {
    // print hello message
    function say(string calldata name) public pure returns (string memory) {
        return string.concat("hello"," ",name);
    }
}

2. Compile the Smart Contract​

This step relies on solc, first check if solc is installed correctly

solc --version

Compile your contract using:

solc --abi --bin --hashes --overwrite -o ./ hello.sol

✅ Successful compilation will generate Hello.abi and Hello.bin files in present directory.

3. Deploy the Smart Contract​

To deploy a smart contract using web3.js, make sure you have installed the web3 package using the following command:

npm install web3

Next, to create a deploy.mjs file, you can use the following code example to write a script that connects to an Ethereum node, compiles the smart contract, and deploys it.

"use strict";

// import required libs
import {readFileSync} from "fs";
import Web3 from "web3";

async function deploy() {
    //  Replace with the node connection to Artela
    let node = '<Artela TestNet>';

    // Replace with the path to your smart contract abi file
    let abiPath = '<Your Contract ABI File>';

    // Replace with the path to your smart contract byte code file 
    let byteCodePath = '<Your Contract BIN File>';

    // Replace with your private key
    let privateKey = '<Your Private Key>';

    const web3 = new Web3(node);

    const deployParams = {
        data: null,
        arguments: null,
    };

    let byteTxt = readFileSync(byteCodePath, "utf-8").toString().trim();
    if (byteTxt.startsWith("0x")) {
        byteTxt = byteTxt.slice(2);
    }

    deployParams.data = byteTxt.trim();

    let abiTxt = readFileSync(abiPath, "utf-8").toString().trim();
    const contractAbi = JSON.parse(abiTxt);

    let account = web3.eth.accounts.privateKeyToAccount(privateKey.trim());
    web3.eth.accounts.wallet.add(account.privateKey);

    // instantiate an instance of demo contract
    let tokenContract = new web3.eth.Contract(contractAbi);

    // deploy contract
    let tokenDeploy = tokenContract.deploy(deployParams);
    let nonceVal = await web3.eth.getTransactionCount(account.address);

    let tokenTx = {
        from: account.address,
        data: tokenDeploy.encodeABI(),
        nonce: nonceVal,
        gasPrice: 1000,

        gas: 7000000,
    };

    let signedTokenTx = await web3.eth.accounts.signTransaction(tokenTx, account.privateKey);
    await web3.eth.sendSignedTransaction(signedTokenTx.rawTransaction).on("receipt", (receipt) => {
        console.log(receipt);
        console.log("contract address: ", receipt.contractAddress);
    });
}

deploy().then();

Make sure to replace the placeholder values in the script with your actual value.

  • Artela TestNet: The node connection to Artela,You can fill in 'https://betanet-rpc1.artela.network'. For more information about testnet, please refer to TestNet Info.
  • Your Private Key: The private key is crucial for signing and executing transactions linked to its associated account. Obtain it by creating a wallet or importing an existing account. Refer to Wallet Configuration for further details.
  • Your Contract ABI File: The path to your smart contract ABI file. like './Hello.abi'.
  • Contract Byte Code File: The path to your smart contract byte code file. like './Hello.bin'.

Run the deployment script.

node deploy.mjs

If the deployment is successful, the script will display the transaction receipt.

{
  blockHash: '0x101473b29461db4d632a194d8ad5d07dabc258b5a2b27f229c784...',
  blockNumber: 210996n,
  contractAddress: '0x65c5c637326a33df07d520b88c671e...',  // Make a note of this value, you will need it.
  cumulativeGasUsed: 3500000n,
  from: '0x58c1b539b469fd15a02da47b52a3...',
  gasUsed: 7000000n,
  logs: [],
  logsBloom: '0x0000000000000000000....',
  status: 1n,
  transactionHash: '0xd4025995d764f7e1c944bab3f048f346c428ee91225f21....',
  transactionIndex: 0n,
  type: 0n
}

Make note of the contractAddress value after successful deployment, as it is required for calling the smart contract.

4. Call the Smart Contract​

To create a call.mjs file, you can use the following code example to write a script that connects to an Ethereum node,and call it.

"use strict";

// import required libs
import {readFileSync} from "fs";
import Web3 from "web3";

async function call() {

    // Replace with the node connection to Artela
    let node = '<Artela TestNet>';
    
    // Replace with your private key
    let privateKey = '<Your Private Key>';
    
    // Replace with the path to your smart contract abi file
    let abiPath = '<Your Contract ABI File>';

    // Replace with the path to your smart contract address
    let contractAddr = '<Your Contract Address>';


    // init connection to Artela node
    const web3 = new Web3(node);

    let account = web3.eth.accounts.privateKeyToAccount(privateKey.trim());
    web3.eth.accounts.wallet.add(account.privateKey);

    let abiTxt = readFileSync(abiPath, "utf-8").toString().trim();
    const contractAbi = JSON.parse(abiTxt);

    // you can replace 'world' here to say others
    let storageInstance = new web3.eth.Contract(contractAbi, contractAddr);
    let instance = await storageInstance.methods["say"]("world").call();
    console.log("call reuslt: " + instance);
}

call().then();

Make sure to replace the placeholder values in the script with your actual value.

  • Artela TestNet: The node connection to Artela,You can fill in 'https://betanet-rpc1.artela.network'. For more information about testnet, please refer to TestNet Info.
  • Your Private Key: The private key is crucial for signing and executing transactions linked to its associated account. Obtain it by creating a wallet or importing an existing account. Refer to Wallet Configuration for further details.
  • Your Contract ABI File: The path to your smart contract ABI file.
  • Your Contract Address: The contract address generated after deploy.

Run the call script.

node call.mjs

If the smart contract call is successful, the script will display the result:

call reuslt: hello world

Congratulations!