Ethereum: Get ABI from a known contract address via ethers.js

Getting the Ethereum Contract ABI with Ethers.js

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

Method 1: Using Ethers.js’s 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 contract ABI from 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);

  }

}


// Example usage:

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, which can be used to call methods and access properties.

Method 2: Using Ethers.js’s abiFromRaw method

The abiFromRaw method allows you to parse an 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);

  }

}


// Example usage:

getAbi('0x..._known_address_here...')

  .then((abi) => console.log(abi))

  .catch((error) => console.error(error));

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

Example Use Case

In your React application, 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 = await getAbi(contractAddress);

  const contractInstance = new ethers.Contract(contractAddress, contractABI, Web3);

  // Use the contract instance to call functions and access properties

}


export default App;

By using Ethers.js’s loadContract or abiFromRaw methods, you can easily obtain an executable Solidity contract bytecode from a known smart contract address and interact with it in your React application.

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