Web3之路——如何开发“Buy Me a Coffee” DeFi dapp

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mkdir BuyMeACoffee-contracts
cd BuyMeACoffee-contracts

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npm init -y

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thatguyintech@albert BuyMeACoffee-contracts % npm init -y
Wrote to /Users/thatguyintech/Documents/co/videos/week2/BuyMeACoffee-contracts/package.json:

{
  "name": "buymeacoffee-contracts",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

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npx hardhat

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npm install --save-dev hardhat@^2.9.3 @nomiclabs/hardhat-waffle@^2.0.0 ethereum-waffle@^3.0.0 chai@^4.2.0 @nomiclabs/hardhat-ethers@^2.0.0 ethers@^5.0.0

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thatguyintech@albert BuyMeACoffee-contracts % tree -C -L 1
.
├── README.md
├── contracts
├── hardhat.config.js
├── node_modules
├── package-lock.json
├── package.json
├── scripts
└── test

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//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));
    }
}

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const hre = require("hardhat");

// Returns the Ether balance of a given address.
async function getBalance(address) {
  const balanceBigInt = await hre.waffle.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);
  });

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npx hardhat run scripts/buy-coffee.js

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thatguyintech@albert BuyMeACoffee-contracts % npx hardhat run scripts/buy-coffee.js
Compiled 1 Solidity file successfully
BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
== start ==
Address 0 balance:  9999.99877086625
Address 1 balance:  10000.0
Address 2 balance:  0.0
== bought coffee ==
Address 0 balance:  9999.99877086625
Address 1 balance:  9998.999752902808629985
Address 2 balance:  3.0
== withdrawTips ==
Address 0 balance:  10002.998724967892122376
Address 1 balance:  9998.999752902808629985
Address 2 balance:  0.0
== memos ==
At 1652033688, Carolina (0x70997970C51812dc3A010C7d01b50e0d17dc79C8) said: "You're the best!"
At 1652033689, Vitto (0x3C44CdDdB6a900fa2b585dd299e03d12FA4293BC) said: "Amazing teacher"
At 1652033690, Kay (0x90F79bf6EB2c4f870365E785982E1f101E93b906) said: "I love my Proof of Knowledge"

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// 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);
  });

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npx hardhat run scripts/deploy.js

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BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3

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thatguyintech@albert BuyMeACoffee-contracts % npx hardhat run scripts/deploy.js
BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
thatguyintech@albert BuyMeACoffee-contracts % npx hardhat run scripts/deploy.js
BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
thatguyintech@albert BuyMeACoffee-contracts % npx hardhat run scripts/deploy.js
BuyMeACoffee deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3

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// 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]
    }
  }
};

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npm install dotenv

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touch .env

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

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node_modules
.env
coverage
coverage.json
typechain

#Hardhat files
cache
artifacts

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npx hardhat run scripts/deploy.js --network goerli

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BuyMeACoffee deployed to: 0xDBa03676a2fBb6711CB652beF5B7416A53c1421D

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// 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);
  });

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// Withdraw funds if there are funds to withdraw.
  if (contractBalance !== "0.0") {
    console.log("withdrawing funds..")
    const withdrawTxn = await buyMeACoffee.withdrawTips();
    await withdrawTxn.wait();
  }

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thatguyintech@albert BuyMeACoffee-contracts % npx hardhat run scripts/withdraw.js
current balance of owner:  0.039608085986833815 ETH
current balance of contract:  0.001 ETH
withdrawing funds..
current balance of owner:  0.040562731986622163 ETH

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const provider = new hre.ethers.providers.AlchemyProvider(
    "goerli",
    process.env.GOERLI_API_KEY
);