Getting an Ethereum ABI Contract with Ethers.js

Ethereum provides several ways to get the executable Solidity contract bytecode (ABI) from a known smart contract address. In this article, we will explore two methods using Ethers.js, a popular JavaScript library for interacting with the Ethereum blockchain.

Method 1: Using Ethers.js’ loadContract Method

The loadContract method allows you to load an existing Solidity contract bytecode from a URI or file path.

const ethers = require('ethers');
// Load an ABI contract from a known address
async function getAbi(address) {
try {
const contract = new ethers.Contract(address, 'YourContract ABI', { gas: 200000 });
constabi = await contract.getABI();
return abi;
} catch (error) {
console.error(error);
}
}
// Usage example:
getAbi('0x..._known_address_here...')
.then((abi) => console.log(abi))
.catch((error) => console.error(error));

In this example, replace “YourContract ABI” with the actual ABI of your smart contract. The loadContract method returns a new instance of the contract object that can be used to call methods and access properties.

Method 2: Using the abiFromRaw Ethers.js method

The abiFromRaw method allows you to parse existing Solidity contract bytecode from a raw string or file.

const ethers = require('ethers');
// Parse contract ABI from known address
async function getAbi(address) {
try {
const raw = '0x..._known_address_here_raw';
const abi = await ethers.utils.abiFromRaw(raw);
return abi;
} catch (error) {
console.error(error);
}
}
// Usage example:
getAbi('0x..._known_address_here...')
.then((abi) => console.log(abi))
.catch((error) => console.error(error));

This method parses the raw bytecode of the contract and returns a new instance of the ethers.utilsABI module that contains the parsed ABI.

Example Use Case

In your React app, you can use Ethers.js to load an existing smart contract bytecode from a known address. For example:

import React from 'react';
import Web3 from 'web3';
import { ethers } from 'ethers';
const Web3 = new Web3(window.ethereum);
function App() {
const contractAddress = '0x..._known_address_here...';
const contractABI = wait getAbi(contractAddress);
const contractInstance = new ethers.Contract(contractAddress, contractABI, Web3);
// Use the contract instance to call functions and access properties
}
export defaultApp;

Using Ethers.js’ loadContract or abiFromRaw methods, you can easily retrieve the executable Solidity contract bytecode from a known smart contract address and interact with it in your React application.