如何在智能合约中存储 ETH？

Question

我正在编写一个 LibraryPortal 智能合约，多个用户可以在其中相互租借他们的书籍。因此，在此合同中，msg.value 包含总金额，即保证金和租金的组合。

我要做的是立即将租金转给图书所有者，并将剩余金额存储在合同中，即保证金。

如果承租人未在指定时间内 return 图书，则保证金将转给图书所有者，否则 return 给承租人。

这是我的片段：

function borrowBook(string _bName) payable returns (string){
    if(msg.sender != books[_bName].owner){
        if(books[_bName].available == true){
            if(getBalance()>=(books[_bName].amtSecurity + books[_bName].rate) ){
                books[_bName].borrower = msg.sender;
                books[_bName].available = false;
                books[_bName].owner.transfer(msg.value - books[_bName].amtSecurity);
                //  Code missing
                //  For storing
                //  ETH into the Contact
                return "Borrowed Succesful";
            }else{
                return "Insufficient Fund";
            }
        }else{
            return "Currently this Book is Not Available!";
        }
    }else{
        return "You cannot Borrow your own Book";
    }
}

Answer 1

您可以通过称为托管合同的东西获得结果。
以下是open-zeppelin对Escrow合约的实现：

contract Escrow is Secondary {
  using SafeMath for uint256;

  event Deposited(address indexed payee, uint256 weiAmount);
  event Withdrawn(address indexed payee, uint256 weiAmount);

  mapping(address => uint256) private _deposits;

  function depositsOf(address payee) public view returns (uint256) {
    return _deposits[payee];
  }

  /**
  * @dev Stores the sent amount as credit to be withdrawn.
  * @param payee The destination address of the funds.
  */
  function deposit(address payee) public onlyPrimary payable {
    uint256 amount = msg.value;
    _deposits[payee] = _deposits[payee].add(amount);

    emit Deposited(payee, amount);
  }

  /**
  * @dev Withdraw accumulated balance for a payee.
  * @param payee The address whose funds will be withdrawn and transferred to.
  */
  function withdraw(address payee) public onlyPrimary {
    uint256 payment = _deposits[payee];

    _deposits[payee] = 0;

    payee.transfer(payment);

    emit Withdrawn(payee, payment);
  }
}

你可以直接在你的合约中实例化合约，然后将资金转发给合约。

要完整实现类似功能，请查看 refundable crowdsale contract

Answer 2

谢谢你们的回答，但后来我才知道随交易一起发送到合约的 VALUE 存储在合约本身中，您可以使用 address(this).balance 访问它始终为您提供合同实例中可用的余额。因此，您不需要任何变量或其他东西来将 ETHER 存储在您的合约中。

如何在智能合约中存储 ETH？

How to store ETH in the Smart Contract?

ethereum

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