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撰写（费用委托）

当您要执行智能合约时，您可以向 feepayer 发送**"交易 "，其中包括支付请求**。

导入 web3 和 @kaiachain/web3js-ext 软件包，在 web3 上添加 kaia 功能

定义发送方、付费方地址和私人密钥

使用指定的 kairos 测试网 URL 设置提供程序。 web3 中的提供者是访问区块链数据的只读抽象。

此外，您还可以将提供商 URL 从 kairos 更改为 quicknode

使用web3.eth.accounts.privateKeyToAccount从定义的私钥创建发送方和缴费方账户

定义合同阿比和合约地址

使用定义了 contractAbi 和 address 的 Web3.eth.Contract创建合约实例。您可以通过该实例读写合约

更新前获取数字的值

使用contract.methods.increment().encodeABI()对合约方法数据进行编码

创建事务以更新编号的值，其类型为 "FeeDelegatedSmartContractExecution"：收费委托智能合约执行

使用 signTransaction 在发送方账户上签署交易

使用 "signTransactionAsFeePayer "以付费方账户签署交易

将交易发送到区块链。它将返回交易收据

获取数字的更新值

smartContractWriteFeeDelegated.js


const { Web3, TxType } = require("@kaiachain/web3js-ext");
const senderAddr = "0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7";
const senderPriv = "0x4a72b3d09c3d5e28e8652e0111f9c4ce252e8299aad95bb219a38eb0a3f4da49";
const feePayerAddr = "0xcb0eb737dfda52756495a5e08a9b37aab3b271da";
const feePayerPriv = "0x9435261ed483b6efa3886d6ad9f64c12078a0e28d8d80715c773e16fc000cff4";
const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");
const web3 = new Web3(provider);
const senderAccount = web3.eth.accounts.privateKeyToAccount(senderPriv);
const feePayerAccount = web3.eth.accounts.privateKeyToAccount(feePayerPriv);
/* compiled in remix.ethereum.org (compiler: 0.8.18, optimizer: false)
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;
contract Counter {
    uint256 public number;
    event SetNumber(uint256 number);
    constructor(uint256 initNumber) {
        number = initNumber;
    }
    function setNumber(uint256 newNumber) public {
        number = newNumber;
        emit SetNumber(number);
    }
    function increment() public {
        number++;
        emit SetNumber(number);
    }
}
*/
const contractAbi = JSON.parse('[{"inputs":[{"internalType":"uint256","name":"initNumber","type":"uint256"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"number","type":"uint256"}],"name":"SetNumber","type":"event"},{"inputs":[],"name":"increment","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"number","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"newNumber","type":"uint256"}],"name":"setNumber","outputs":[],"stateMutability":"nonpayable","type":"function"}]');
const contractAddr = "0x95Be48607498109030592C08aDC9577c7C2dD505";
async function main() {
  const contract = new web3.eth.Contract(contractAbi, contractAddr);
  console.log("number before", (await contract.methods.number().call()).toString());
  const data = contract.methods.increment().encodeABI();
  const tx = {
    type: TxType.FeeDelegatedSmartContractExecution,
    from: senderAddr,
    to: contractAddr,
    data: data,
  };
  // Sign transaction by sender
  const signResult1 = await senderAccount.signTransaction(tx);
  console.log("senderTxHashRLP", signResult1.rawTransaction);
  // Sign and send transaction by fee payer
  const signResult2 = await feePayerAccount.signTransactionAsFeePayer(signResult1.rawTransaction);
  console.log("signedTx", signResult2.transactionHash);
  const receipt = await web3.eth.sendSignedTransaction(signResult2.rawTransaction);
  console.log("receipt", receipt);
  console.log("number after", (await contract.methods.number().call()).toString());
}
main();

output


❯ node smartContractWriteFeeDelegated.js
number before 296
senderTxHashRLP 0x31f8844c850ba43b7400830111939495be48607498109030592c08adc9577c7c2dd505809424e8efd18d65bcb6b3ba15a4698c0b0d69d13ff784d09de08af847f8458207f6a03a9ade9fb5c2e4e513c56341ab64ad0a70613d826479f2117b53d3b57cee5021a07612c8538ee5b895f44b50858164dd67da473e264c29d331437273e581652eea
signedTx 0x66f7d99d2236145baa4bb84f66d283c508639bd6150c68b300323f7aa016676f
receipt {
  blockHash: '0x6b2201b6bcc999395e247fc8b85062b1a9313cc0db53a50a746203c9995af8b9',
  blockNumber: 148743711n,
  cumulativeGasUsed: 38014n,
  effectiveGasPrice: 25000000000n,
  from: '0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7',
  gasUsed: 38014n,
  logs: [
    {
      address: '0x95be48607498109030592c08adc9577c7c2dd505',
      topics: [Array],
      data: '0x0000000000000000000000000000000000000000000000000000000000000129',
      blockNumber: 148743711n,
      transactionHash: '0x66f7d99d2236145baa4bb84f66d283c508639bd6150c68b300323f7aa016676f',
      transactionIndex: 0n,
      blockHash: '0x6b2201b6bcc999395e247fc8b85062b1a9313cc0db53a50a746203c9995af8b9',
      logIndex: 0n,
      removed: false
    }
  ],
  logsBloom: '0x00000000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000001200000002',
  status: 1n,
  to: '0x95be48607498109030592c08adc9577c7c2dd505',
  transactionHash: '0x66f7d99d2236145baa4bb84f66d283c508639bd6150c68b300323f7aa016676f',
  transactionIndex: 0n,
  type: 0n
}
number after 297