使用计数器作为 ID - 在智能合约中是个好主意吗？

Question

我编写了以下代码来跟踪智能合约中的存款。 我需要能够在未来的功能中引用个人存款。

pragma solidity ^0.8.4;

contract DepositsWithIds {
    address owner;

    struct Deposit {
        uint256 depositAmount;
        address depositor;
        uint256 counter;
    }

    constructor() payable {
    owner = msg.sender;
    }
  
    Deposit[] public activeDeposits;

    event DepositMade(address, uint256, uint256);

    function deposit() public payable returns (uint256 counter) {

        return ++counter;

        Deposit memory newDeposit = Deposit(

        msg.value,
        msg.sender,
        counter
    );

    activeDeposits.push(newDeposit);

    emit DepositMade(msg.sender, msg.value, counter);

    }
}

使用柜台作为唯一的存款 ID 是个好主意吗？ 在编写下一个函数时，如何将activeDeposits.counter 连接到activeDeposits.depositor？

Answer 1

uint public counter;

mapping(uint = > Deposit) public ids; 

function deposit() public payable {

    Deposit storage _deposit = ids[_counter]; 

    _deposit.depositAmount = msg.value; 

    _deposit.depositor = msg.sender;
    
    activeDeposits.push(_deposit);

    _counter++; 

    emit DepositMade(msg.sender, msg.value);
}

Answer 2

您可以将 counter 移出结构：

struct Deposit {
    uint256 depositAmount;
    address depositor;
}

您将计数器设置为顶级状态变量

uint256 counter;

你可以有一个将 counterId 映射到 Deposit 的映射

mapping(uint156=>Deposti) public idToDeposit;

然后通过id获取押金

function getDepositByID(uint id)public view {
     idToDeposit[id]
}

• 您可能会遇到openzeppelin Counters.sol来使用计数器

你安装npm i @openzeppelin/contracts，导入``Counters

 import "../node_modules/@openzeppelin/contracts/utils/Counters.sol";

在你的合同中：

contract Test{
       // this means all Counters.Counter types in your contract loaded with the methods of Counters library
       using Counters for Counters.Counter;
       Counters.Counter private depositIds;
}