使用 replit ，它是一个基于 IDE 进行编程的浏览器。

1.在 repli 上注册一个免费帐户并登录；

2.点击左上角的create创建；

3.选择nods.js

4.npm install ethers got@11.8.2

这将安装 ethers ，一个用于与 Ethereum 一起工作的库， got ，一个用于发出 HTTP 请求的库。 您可能会看到一些关于缺少 package.json 的警告，您可以忽略这些警告。

5.这样就算安装成功.

6.还需要一个以太坊节点来与 Facaster Registry 合约对话。 建议使用 Alchemy 。 如果您是第一次注册，以下步骤可能会略有不同：

7.注册 Alchemy.com ，登录

8.选择以太坊作为区块链，点击get started

9.team name和app name随便取，网络选择Rinkeby，点击Create APP。

10.选择第一个免费的，点击continue。

11.点击跳过。

12.继续点击跳过。

13.点击continue。

14.随便输入什么,点击let‘s go。

15.点击view details。

16.点击view key。

17.复制代码，把箭头标记的xxxxxxxxxxxxxxxxxx处换成你alchemy的api key:

18.把下面代码复制粘贴到index.js这个文件下，run运行。

const { providers, Contract, utils } = require("ethers"); const got = require("got");

const doStuff = async () => { const ALCHEMY_SECRET = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'; const provider = new providers.AlchemyProvider('rinkeby', ALCHEMY_SECRET);

const block = await provider.getBlockNumber();

console.log("The latest Ethereum block is:", block);

const REGISTRY_CONTRACT_ADDRESS = '0xe3Be01D99bAa8dB9905b33a3cA391238234B79D1' const REGISTRY_ABI = [ { name: 'getDirectoryUrl', inputs: [{ internalType: 'bytes32', name: 'username', type: 'bytes32' }], outputs: [{ internalType: 'string', name: '', type: 'string'}], stateMutability: 'view', type: 'function', }, { inputs: [{ internalType: 'address', name: '', type: 'address' }], name: 'addressToUsername', outputs: [{ internalType: 'bytes32', name: '', type: 'bytes32' }], stateMutability: 'view', type: 'function', }, ];

const registryContract = new Contract(REGISTRY_CONTRACT_ADDRESS, REGISTRY_ABI, provider);

const username = 'v'; const byte32Name = utils.formatBytes32String(username); const directoryUrl = await registryContract.getDirectoryUrl(byte32Name); console.log(`${username}'s Host is located at: ${directoryUrl} \n`);

const directoryResponse = await got(directoryUrl); const directory = JSON.parse(directoryResponse.body); console.log(`${username}'s Directory is: `); console.log(directory, '\n');

const addressActivityUrl = directory.body.addressActivityUrl; const addressActivityResponse = await got(addressActivityUrl); const addressActivity = JSON.parse(addressActivityResponse.body); const cast = addressActivity[0]; console.log(`${username}'s most recent Cast was: `) console.log(cast, '\n')

const stringifiedCastBody = JSON.stringify(cast.body); const calculatedHash = utils.keccak256(utils.toUtf8Bytes(stringifiedCastBody)); const expectedHash = cast.merkleRoot;

if (calculatedHash !== expectedHash) { console.log(`FAILED: the calculated hash ${calculatedHash} does not match the one in the cast: ${expectedHash}`); } else { console.log(`PASSED: the calculated hash ${calculatedHash} matches the one in the cast`); }

const recoveredAddress = utils.verifyMessage(cast.merkleRoot, cast.signature); const expectedAddress = cast.body.address;

if (recoveredAddress !== expectedAddress) { console.log( `Failed: the recovered address ${recoveredAddress} does not match the address provided in the cast ${expectedAddress}` ); } else { console.log(`PASSED: the recovered address ${recoveredAddress} matches the one in the cast`); }

const encodedUsername = await registryContract.addressToUsername(expectedAddress); const expectedUsername = utils.parseBytes32String(encodedUsername); const castUsername = cast.body.username;

if (expectedUsername !== castUsername) { console.log(`FAILED: ${expectedAddress} does not own ${castUsername}, it owns ${expectedUsername}`); } else { console.log(`PASSED: ${expectedAddress} owns ${castUsername}`); } }

doStuff();

19.运行得到以下结果，祝贺你成功了。

官网教程：

https://www.farcaster.xyz/docs/fetch-casts

如果有什么不懂得。可以推特私信@LuobuH