Getting started with Solidity – Part 3 on the Sepolia testnet | Benjamin Duffield-Harding | Coins | March 2024

transaction log

One last thing before deploying.

I would like to modify the smart contract so that I can view the transaction history in Etherscan (block explorer) later when making a deposit or withdrawal.

Solidity allows you to use events to publish transaction logs to the blockchain.

Now the contract is:

pragma solidity ^0.8.4;
contract owned 
bool public paused;
address owner;
constructor() 
owner = msg.sender;
modifier onlyOwner 
require(msg.sender == owner, "Only contract owner can call this function");
_;

contract pausable is owned 
function setPaused(bool _paused) public onlyOwner 
paused = _paused;

contract Faucet is pausable 
// Events
event Withdrawal(address indexed to, uint amount);
event Deposit(address indexed from, uint amount);
function withdraw(uint withdraw_amount) public 
require(paused == false, "Function paused");
require(withdraw_amount <= 0.1 ether, "Withdrawals are limited to 0.1 ether");
require(address(this).balance >= withdraw_amount, "Insufficient balance in faucet");
payable(msg.sender).transfer(withdraw_amount);
// event data -> transaction logs
emit Withdrawal(msg.sender, withdraw_amount);
function deposit() public payable 
// event data -> transaction logs
emit Deposit(msg.sender,msg.value);

Don’t forget to compile the updated contract.

npx hardhat compile