Interacting with AAVE Smart Contracts Using Web3

As a blockchain developer, you may want to interact directly with the AAVE smart contracts using the Web3 library. In this article, we’ll provide a detailed guide on how to do this, including examples of common actions such as lending and borrowing assets, getting the current interest rates, and checking the balance of a contract.

Before we begin, make sure you have a Web3 provider set up and connected to the Ethereum network. You can use a local Ethereum node such as Ganache, or a public node such as Infura. You’ll also need the ABI (Application Binary Interface) and contract addresses of the AAVE smart contracts you want to interact with. You can find these in the AAVE documentation.

Lending and Borrowing Assets

To lend or borrow assets using the AAVE smart contracts, you’ll need to use the LendingPool contract for the asset. The LendingPool contract has methods for lending and borrowing both stable (fixed rate) and variable (market rate) loans.

To lend an asset using the stable rate model, you can use the lendStable() method of the LendingPool contract. This method takes three arguments: the asset to lend (in the form of a contract address), the amount to lend (in wei), and the duration of the loan (in seconds). For example:

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.lendStable('0xDAIContractAddress', '100000000', '86400').send({ from: '0xMyWalletAddress' }); // lend 100 DAI for 1 day (86400 seconds)

To borrow an asset using the stable rate model, you can use the borrowStable() method of the LendingPool contract. This method takes the same arguments as the lendStable() method. For example:

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.borrowStable('0xDAIContractAddress', '100000000', '86400').send({ from: '0xMyWalletAddress' }); // borrow 100 DAI for 1 day (86400 seconds)

To lend an asset using the variable rate model, you can use the lendVariable() method of the LendingPool contract. This method takes two arguments: the asset to lend (in the form of a contract address), and the amount to lend (in wei). For example:

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.lendVariable('0xETHContractAddress', '100000000').send({ from: '0xMyWalletAddress' }); // lend 100 ETH

To borrow an asset using the variable rate model, you can use the borrowVariable() method of the LendingPool contract. This method takes the same arguments as the lendVariable() method. For example:

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.borrowVariable('0xETHContractAddress', '100000000').send({ from: '0xMyWalletAddress' }); // borrow 100 ETH

Getting Interest Rates

To get the current interest rate for an asset in the lending pool, you can use the getCurrentVariableInterestRate() method of the LendingPool contract. This method takes no arguments and returns the current interest rate as a BigNumber object. For example:

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
const interestRate = await lendingPool.methods.getCurrentVariableInterestRate().call(); // get the current interest rate for the asset

To get the minimum collateralization ratio for an asset in the price oracle, you can use the getMinimumCollateralizationRatio() method of the PriceOracle contract. This method takes no arguments and returns the minimum collateralization ratio as a BigNumber object. For example:

const priceOracle = new web3.eth.Contract(PriceOracle_ABI, '0xAAvePriceOracleAddress'); // get the PriceOracle contract
const minCollateralizationRatio = await priceOracle.methods.getMinimumCollateralizationRatio().call(); // get the minimum collateralization ratio for the asset

Checking Balances

To check the balance of a contract or wallet address, you can use the balanceOf() method of the ERC20 contract for the asset. This method takes an address as an argument and returns the balance of that address as a BigNumber object. For example:

const erc20 = new web3.eth.Contract(ERC20_ABI, '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE'); // get the ERC20 contract for the asset
const balance = await erc20.methods.balanceOf('0xMyWalletAddress').call(); // get the balance of my wallet address

Conclusion

In this article, we’ve provided a detailed guide on how to interact with the AAVE smart contracts using the Web3 library. We’ve covered common actions such as lending and borrowing assets, getting the current interest rates, and checking the balance of a contract. With this knowledge, you should be able to write your own Ethereum applications that make use of the AAVE protocol and its various smart contracts.

If you have any questions or need further assistance, you can refer to the AAVE documentation or reach out to the AAVE community for support.

As always, make sure to thoroughly test your code and carefully review the contract terms before interacting with any smart contracts on the Ethereum network. Good luck and happy coding!

Exercises

To review these concepts, we will go through a series of exercises designed to test your understanding and apply what you have learned.

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.lendStable('0xDAIContractAddress', '100000000', '86400').send({ from: '0xMyWalletAddress' }); // lend 100 DAI for 1 day (86400 seconds)

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
await lendingPool.methods.borrowStable('0xDAIContractAddress', '100000000', '86400').send({ from: '0xMyWalletAddress' }); // borrow 100 DAI for 1 day (86400 seconds)

const lendingPool = new web3.eth.Contract(LendingPool_ABI, '0xAAveLendingPoolAddress'); // get the LendingPool contract
const interestRate = await lendingPool.methods.getCurrentVariableInterestRate().call(); // get the current interest rate for the asset

const priceOracle = new web3.eth.Contract(PriceOracle_ABI, '0xAAvePriceOracleAddress'); // get the PriceOracle contract
const minCollateralizationRatio = await priceOracle.methods.getMinimumCollateralizationRatio().call(); // get the minimum collateralization ratio for the asset

const erc20 = new web3.eth.Contract(ERC20_ABI, '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE'); // get the ERC20 contract for the asset
const balance = await erc20.methods.balanceOf('0xMyWalletAddress').call(); // get the balance of my wallet address