Read

您可以通过 "调用 "RPC API 调用智能合约中的函数。 在这里可以调用的功能仅限于视图函数，不会改变合约中的任何状态。

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

使用指定的 kairos 测试网 URL 设置提供程序。 web3js 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

定义合同 Abi 和 addreess，可从编译后的 solidity 代码中获取

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

调用已创建合约的号函数并打印结果

smartContractRead.js

const { Web3 } = require("@kaiachain/web3js-ext");

const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");

const web3 = new Web3(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 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);

const number = await contract.methods.number().call();

console.log("number", number.toString());

}

main();

output

node smartContractRead.js

number 294