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Write (Fee Delegation)

當您要執行智能合約時，您可以向 feepayer 發送**"交易 "，其中包括支付請求**。

導入 ethers 和 @kaiachain/ethers-ext 模塊，在 ethers.js 上添加 kaia 功能。

定義 發件人、繳費人地址和發件人私人密鑰

使用指定的 kairos 測試網 URL 設置提供程序。以太坊中的提供者是訪問區塊鏈數據的只讀抽象。

此外，您還可以將提供商 URL 從 kairos 更改為 quicknode

使用發件人的私人密鑰和提供商創建發件人錢包

使用發送者的私人密鑰和提供者的私人密鑰創建付費者錢包

設置由 solidity 代碼生成的 Abi

定義與之交互的合約地址

使用 ethers.Contract創建合約實例，填寫參數 contractAddr、abi、provider。您可以通過該實例讀寫合約

使用counter.number()方法從合約中獲取數字的值

創建事務數據以更新編號值

用上一步的數據創建一個事務對象

用發件人的錢包簽署交易

使用付費者的錢包將交易發送到區塊鏈上。函數 "sendTransactionAsFeePayer "會在發送者的簽名上添加一個帶有 FeePayer 私鑰的簽名，並將其傳輸到區塊鏈網絡。

使用方法 counter.number() 獲取更新值 number

writeWithFeeDelegation.js

const ethers = require("ethers");

const { Wallet, TxType } = require("@kaiachain/ethers-ext/v5");

const senderAddr = "0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7";

const senderPriv = "0x4a72b3d09c3d5e28e8652e0111f9c4ce252e8299aad95bb219a38eb0a3f4da49";

const feePayerAddr = "0xcb0eb737dfda52756495a5e08a9b37aab3b271da";

const feePayerPriv = "0x9435261ed483b6efa3886d6ad9f64c12078a0e28d8d80715c773e16fc000cff4";

const provider = new ethers.providers.JsonRpcProvider("https://public-en-kairos.node.kaia.io");

const senderWallet = new Wallet(senderPriv, provider);

const feePayerWallet = new Wallet(feePayerPriv, provider);

/* 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 abi = '[{"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 counter = new ethers.Contract(contractAddr, abi, senderWallet);

console.log("number before", (await counter.number()).toString());

const data = (await counter.populateTransaction.increment()).data;

const tx = {

type: TxType.FeeDelegatedSmartContractExecution,

from: senderAddr,

to: contractAddr,

value: 0,

data: data,

};

// Sign transaction by sender

const populatedTx = await senderWallet.populateTransaction(tx);

const senderTxHashRLP = await senderWallet.signTransaction(populatedTx);

console.log("senderTxHashRLP", senderTxHashRLP);

// Sign and send transaction by fee payer

const sentTx = await feePayerWallet.sendTransactionAsFeePayer(senderTxHashRLP);

const receipt = await sentTx.wait();

console.log("receipt", receipt);

console.log("number after", (await counter.number()).toString());

}

main();

output

❯ node writeWithFeeDelegation.js

number before 293

senderTxHashRLP 0x31f88447850ba43b7400830111939495be48607498109030592c08adc9577c7c2dd505809424e8efd18d65bcb6b3ba15a4698c0b0d69d13ff784d09de08af847f8458207f6a0d9d8ebf8d1c2665cf27903234536edc078bf2857a42941a140a8617b2ca1cb7aa05006695b49733abd7dbbb4e5192d81b1f1e84efb1cf919dee6f2d4687aa32fe2

receipt {

to: '0x95Be48607498109030592C08aDC9577c7C2dD505',

from: '0x24e8eFD18D65bCb6b3Ba15a4698c0b0d69d13fF7',

contractAddress: null,

transactionIndex: 0,

gasUsed: BigNumber { _hex: '0x947e', _isBigNumber: true },

logsBloom: '0x00000000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000001200000002',

blockHash: '0x9ab3f98ef92495c3a6c4b7f353ae60459d2d96cf8d3270c3285c398fd3ee912a',

transactionHash: '0xa4ea502904b63b098e650d82c69999c1537ff2426b9f391f2f16b027f00656d4',

logs: [

{

transactionIndex: 0,

blockNumber: 148740703,

transactionHash: '0xa4ea502904b63b098e650d82c69999c1537ff2426b9f391f2f16b027f00656d4',

address: '0x95Be48607498109030592C08aDC9577c7C2dD505',

topics: [Array],

data: '0x0000000000000000000000000000000000000000000000000000000000000126',

logIndex: 0,

blockHash: '0x9ab3f98ef92495c3a6c4b7f353ae60459d2d96cf8d3270c3285c398fd3ee912a'

}

],

blockNumber: 148740703,

confirmations: 2,

cumulativeGasUsed: BigNumber { _hex: '0x947e', _isBigNumber: true },

effectiveGasPrice: BigNumber { _hex: '0x05d21dba00', _isBigNumber: true },

status: 1,

type: 0,

byzantium: true

}

number after 294