百亿项目Alchemy Road to Web3 第二周NFT获取教程

August 12th, 2022

Alchemy是什么项目？

2019年12月，Alchemy完成1500万美元A轮融资，资方为Pantera Capital，斯坦福大学，Coinbase，三星等。

2021年4月，Alchemy以5.05亿美元估值完成8000万美元B轮融资，Coatue和Addition领投，DFJ Growth、K5 Global、Chainsmokers（烟鬼组合）、演员Jared Leto和Glazer家族参投。

2021年10月，Alchemy以35亿美元估值完成2.5亿美元C轮融资，由a16z领投的。

2022年2月，Alchemy以102亿美元估值完成2亿美元融资，Lightspeed与Silver Lake领投。

Alchemy是一个背景强大、经费充足、踏实做事、没有发币的团队，这样的项目不刷，难道去刷土狗吗？

并且，Alchemy计划将新资金用于推广Web3采用，这方面的一些举措包括推出Web3 University，就是现在的 Road to Web3 活动，活动为期10周，每周一个NFT。看了下nft数量极少，估计由于任务难度大，很多小伙伴直接放弃，这样的项目若是空投，绝对是大毛。

手把手第二周教程开始：如何构建“给我买杯咖啡”的 DeFi dapp

官方原版教程链接，其中有长达1小时30分钟的视频教程还有大篇幅的文字教程，并且有错误。我按照我的做法给大家一个易于操作的图文教程。

step1 安装环境

1.2022最新Nodejs下载安装配置步骤（保姆级教程）

先按照上述教程安装Nodejs，共分为5步，前3步做完就正常了，我没有做第4和第5步，不放心可以做一下。最新版本号如下：

2.VScode安装教程（超详细版）

再按照这个教程安装VScode。

step2 对 BuyMeACoffee.sol 智能合约进行编码

1.按win+R调出命令框，输入cmd，进入控制台。

2.输入mkdir BuyMeACoffee-contracts按回车创建文件夹，再输入cd BuyMeACoffee-contracts 按回车进入该文件夹。

3.输入npm init -y 开始新项目。

4.输入npx hardhat创建示例项目。

5.之后连按三下回车，出现下图。

6.按照提示输入下面代码，坐等安装完毕。出现警告不管。

npm install --save-dev "hardhat@^2.10.1" "@nomicfoundation/hardhat-toolbox@^1.0.1"

7.打开vscode，点击file，点击open folder。

8.找到刚才创建的BuyMeACoffee-contracts文件夹，点击选择文件夹。

9.打开后如图所示。

10.右键rename将合约文件lock.sol重命名为 BuyMeACoffee.sol

11.BuyMeACoffee.sol代码替换成下面的并保存！（不保存没用啊，要点保存）

//SPDX-License-Identifier: Unlicense

// contracts/BuyMeACoffee.sol
pragma solidity ^0.8.0;

// Switch this to your own contract address once deployed, for bookkeeping!
// Example Contract Address on Goerli: 0xDBa03676a2fBb6711CB652beF5B7416A53c1421D

contract BuyMeACoffee {
    // Event to emit when a Memo is created.
    event NewMemo(
        address indexed from,
        uint256 timestamp,
        string name,
        string message
    );
    
    // Memo struct.
    struct Memo {
        address from;
        uint256 timestamp;
        string name;
        string message;
    }
    
    // Address of contract deployer. Marked payable so that
    // we can withdraw to this address later.
    address payable owner;

    // List of all memos received from coffee purchases.
    Memo[] memos;

    constructor() {
        // Store the address of the deployer as a payable address.
        // When we withdraw funds, we'll withdraw here.
        owner = payable(msg.sender);
    }

    /**
     * @dev fetches all stored memos
     */
    function getMemos() public view returns (Memo[] memory) {
        return memos;
    }

    /**
     * @dev buy a coffee for owner (sends an ETH tip and leaves a memo)
     * @param _name name of the coffee purchaser
     * @param _message a nice message from the purchaser
     */
    function buyCoffee(string memory _name, string memory _message) public payable {
        // Must accept more than 0 ETH for a coffee.
        require(msg.value > 0, "can't buy coffee for free!");

        // Add the memo to storage!
        memos.push(Memo(
            msg.sender,
            block.timestamp,
            _name,
            _message
        ));

        // Emit a NewMemo event with details about the memo.
        emit NewMemo(
            msg.sender,
            block.timestamp,
            _name,
            _message
        );
    }

    /**
     * @dev send the entire balance stored in this contract to the owner
     */
    function withdrawTips() public {
        require(owner.send(address(this).balance));
    }
}

step3 创建一个 buy-coffee.js 脚本来测试你的合约

1.将deploy.js重命名为buy-coffee.js

并将代码替换成下面的：（不保存没用啊，要点保存）

const hre = require("hardhat");

// Returns the Ether balance of a given address.
async function getBalance(address) {
  const balanceBigInt = await hre.ethers.provider.getBalance(address);
  return hre.ethers.utils.formatEther(balanceBigInt);
}

// Logs the Ether balances for a list of addresses.
async function printBalances(addresses) {
  let idx = 0;
  for (const address of addresses) {
    console.log(`Address ${idx} balance: `, await getBalance(address));
    idx ++;
  }
}

// Logs the memos stored on-chain from coffee purchases.
async function printMemos(memos) {
  for (const memo of memos) {
    const timestamp = memo.timestamp;
    const tipper = memo.name;
    const tipperAddress = memo.from;
    const message = memo.message;
    console.log(`At ${timestamp}, ${tipper} (${tipperAddress}) said: "${message}"`);
  }
}

async function main() {
  // Get the example accounts we'll be working with.
  const [owner, tipper, tipper2, tipper3] = await hre.ethers.getSigners();

  // We get the contract to deploy.
  const BuyMeACoffee = await hre.ethers.getContractFactory("BuyMeACoffee");
  const buyMeACoffee = await BuyMeACoffee.deploy();

  // Deploy the contract.
  await buyMeACoffee.deployed();
  console.log("BuyMeACoffee deployed to:", buyMeACoffee.address);

  // Check balances before the coffee purchase.
  const addresses = [owner.address, tipper.address, buyMeACoffee.address];
  console.log("== start ==");
  await printBalances(addresses);

  // Buy the owner a few coffees.
  const tip = {value: hre.ethers.utils.parseEther("1")};
  await buyMeACoffee.connect(tipper).buyCoffee("Carolina", "You're the best!", tip);
  await buyMeACoffee.connect(tipper2).buyCoffee("Vitto", "Amazing teacher", tip);
  await buyMeACoffee.connect(tipper3).buyCoffee("Kay", "I love my Proof of Knowledge", tip);

  // Check balances after the coffee purchase.
  console.log("== bought coffee ==");
  await printBalances(addresses);

  // Withdraw.
  await buyMeACoffee.connect(owner).withdrawTips();

  // Check balances after withdrawal.
  console.log("== withdrawTips ==");
  await printBalances(addresses);

  // Check out the memos.
  console.log("== memos ==");
  const memos = await buyMeACoffee.getMemos();
  printMemos(memos);
}

// We recommend this pattern to be able to use async/await everywhere
// and properly handle errors.
main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

如果你粘贴的是官网的，记得把第五行那个位置换成ethers！！！（如下图所示）

2.在控制台输入npx hardhat run scripts/buy-coffee.js，出现下图就对了。

step4 使用 Alchemy 和 MetaMask 将您的 BuyMeACoffe.sol 智能合约部署到以太坊 Goerli 测试网

1.右键点击scipts，点击new file，创建一个名为deploy.js的文件。

2.在deploy.js中粘贴以下代码。（不保存没用啊，要点保存）

// scripts/deploy.js

const hre = require("hardhat");

async function main() {
  // We get the contract to deploy.
  const BuyMeACoffee = await hre.ethers.getContractFactory("BuyMeACoffee");
  const buyMeACoffee = await BuyMeACoffee.deploy();

  await buyMeACoffee.deployed();

  console.log("BuyMeACoffee deployed to:", buyMeACoffee.address);
}

// We recommend this pattern to be able to use async/await everywhere
// and properly handle errors.
main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

3.在控制台输入npx hardhat run scripts/deploy.js ，并按回车，出现下面那句BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3就对了。

4.打开你的 hardhat.config.js文件，您将看到一些示例部署代码。删除它并将此版本粘贴到其中。记得保存。

// hardhat.config.js

require("@nomiclabs/hardhat-ethers");
require("@nomiclabs/hardhat-waffle");
require("dotenv").config()

// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more

const GOERLI_URL = process.env.GOERLI_URL;
const PRIVATE_KEY = process.env.PRIVATE_KEY;

/**
 * @type import('hardhat/config').HardhatUserConfig
 */
module.exports = {
  solidity: "0.8.4",
  networks: {
    goerli: {
      url: GOERLI_URL,
      accounts: [PRIVATE_KEY]
    }
  }
};

5.在控制台输入npm install dotenv，安装dotenv。如图所示。

6.在控制台输入echo test>.env 创建一个.env文件

在这里可以看到。

7.将以下代码粘贴进.env

GOERLI_URL=https://eth-goerli.alchemyapi.io/v2/<your api key>
GOERLI_API_KEY=<your api key>
PRIVATE_KEY=<your metamask api key>

注意：第7步的这三行代码不是最终的，三行全部要换成自己对应的链接，在哪里找，往下看。

8.替换GOERLI_URL。

注册一个 Alchemy帐户。进入dashboard，点击create app。

然后如下设置，点击create app。

点击view key

复制HTTPS的框内内容，切换到vscode，粘贴到如下位置。

9.替换GOERLI_API_KEY。

将API KEY框内内容复制，然后切换到vscode粘贴到如下位置。

10.替换PRIVATE_KEY。

点击metamask右上角三个点，然后点击账户详情。

点击导出私钥。

将下图内容复制。

粘贴到这里，然后保存。

11.访问 https://www.goerlifaucet.com 并使用您的 Alchemy 帐户登录以获得一些免费的测试以太币。

12.运行部署脚本npx hardhat run scripts/deploy.js --network goerli ，发现报错，把缺的这个装上去就好了，见13步。

13.直接输入npm install --save-dev @nomiclabs/hardhat-waffle 安装第11步的缺的包。安装时有一堆warn不需要管。

14.再运行npx hardhat run scripts/deploy.js --network goerli ，出现下面那行BuyMeACoffee deployed to: 某个地址（这个地址记得复制粘贴下来）就对了。

step5 实施一个withdraw脚本

1.右键点击script创建withdraw.js文件，将下列代码粘贴进去。

// scripts/withdraw.js

const hre = require("hardhat");
const abi = require("../artifacts/contracts/BuyMeACoffee.sol/BuyMeACoffee.json");

async function getBalance(provider, address) {
  const balanceBigInt = await provider.getBalance(address);
  return hre.ethers.utils.formatEther(balanceBigInt);
}

async function main() {
  // Get the contract that has been deployed to Goerli.
  const contractAddress="0xDBa03676a2fBb6711CB652beF5B7416A53c1421D";
  const contractABI = abi.abi;

  // Get the node connection and wallet connection.
  const provider = new hre.ethers.providers.AlchemyProvider("goerli", process.env.GOERLI_API_KEY);

  // Ensure that signer is the SAME address as the original contract deployer,
  // or else this script will fail with an error.
  const signer = new hre.ethers.Wallet(process.env.PRIVATE_KEY, provider);

  // Instantiate connected contract.
  const buyMeACoffee = new hre.ethers.Contract(contractAddress, contractABI, signer);

  // Check starting balances.
  console.log("current balance of owner: ", await getBalance(provider, signer.address), "ETH");
  const contractBalance = await getBalance(provider, buyMeACoffee.address);
  console.log("current balance of contract: ", await getBalance(provider, buyMeACoffee.address), "ETH");

  // Withdraw funds if there are funds to withdraw.
  if (contractBalance !== "0.0") {
    console.log("withdrawing funds..")
    const withdrawTxn = await buyMeACoffee.withdrawTips();
    await withdrawTxn.wait();
  } else {
    console.log("no funds to withdraw!");
  }

  // Check ending balance.
  console.log("current balance of owner: ", await getBalance(provider, signer.address), "ETH");
}

// We recommend this pattern to be able to use async/await everywhere
// and properly handle errors.
main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

如图所示，记得保存。