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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");

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