ERC721 (NFT) - skka3134

用 Wizard 开发合约
https://docs.openzeppelin.com/contracts/4.x/wizard
可铸造 : mint nft
自动增量 Ids : id 自动增持
可销毁：销毁 nft
可暂停：暂停 nft 转移
可枚举：查看总发行量
URI 存储 : nft 的 uri
可拥有：所有权控制，一个管理员
角色：所有权控制，多个管理员
透明：透明代理
UUPS : 代理合约解决可冲突问题

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721EnumerableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721URIStorageUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/security/PausableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/cryptography/draft-EIP712Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/extensions/draft-ERC721VotesUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/utils/CountersUpgradeable.sol";

/// @custom:security-contact [email protected]
contract Dragon is Initializable, ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable, PausableUpgradeable, OwnableUpgradeable, ERC721BurnableUpgradeable, EIP712Upgradeable, ERC721VotesUpgradeable {
    using CountersUpgradeable for CountersUpgradeable.Counter;

    CountersUpgradeable.Counter private _tokenIdCounter;

    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }

    function initialize() initializer public {
        __ERC721_init("Dragon", "Drag");
        __ERC721Enumerable_init();
        __ERC721URIStorage_init();
        __Pausable_init();
        __Ownable_init();
        __ERC721Burnable_init();
        __EIP712_init("Dragon", "1");
        __ERC721Votes_init();
    }

    function pause() public onlyOwner {
        _pause();
    }

    function unpause() public onlyOwner {
        _unpause();
    }

    function safeMint(address to, string memory uri) public onlyOwner {
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function _beforeTokenTransfer(address from, address to, uint256 tokenId, uint256 batchSize)
        internal
        whenNotPaused
        override(ERC721Upgradeable, ERC721EnumerableUpgradeable)
    {
        super._beforeTokenTransfer(from, to, tokenId, batchSize);
    }

    // The following functions are overrides required by Solidity.

    function _afterTokenTransfer(address from, address to, uint256 tokenId, uint256 batchSize)
        internal
        override(ERC721Upgradeable, ERC721VotesUpgradeable)
    {
        super._afterTokenTransfer(from, to, tokenId, batchSize);
    }

    function _burn(uint256 tokenId)
        internal
        override(ERC721Upgradeable, ERC721URIStorageUpgradeable)
    {
        super._burn(tokenId);
    }

    function tokenURI(uint256 tokenId)
        public
        view
        override(ERC721Upgradeable, ERC721URIStorageUpgradeable)
        returns (string memory)
    {
        return super.tokenURI(tokenId);
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}

remix https://remix.ethereum.org/
去掉 safeMint 的 onlyOwner，所有人都可 mint

    function safeMint(address to, string memory uri) public onlyOwner {
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function safeMint(address to, string memory uri) public  {
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

定义一个最大发行量

    uint256 MAX = 1000;
    function safeMint(address to, string memory uri) public  {
        require(_tokenIdCounter.current() <= MAX, "exceed");
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

上传元数据到 IPFS
https://console.filebase.com/
元数据的格式是 JSON

{
    "description": "dragon", 
    "external_url": "https://openseacreatures.io/3", 
    "image": "https://ipfs.filebase.io/ipfs/QmewcWVm6zmnCEwDzZSanrzdFNdzCF8X4Tfo5Qi87Qdhrf", 
    "name": "dragon",
    "attributes": [
      {
        "trait_type": "Base", 
        "value": "Starfish"
      }, 
      {
        "trait_type": "Eyes", 
        "value": "Big"
      }, 
      {
        "trait_type": "Mouth", 
        "value": "Surprised"
      }, 
      {
        "trait_type": "Level", 
        "value": 5
      }   
    ]
  }

7. 修改代码

    string  uri="ipfs://QmPHcbAwnaGkGm939xRzhwXuYVe12iqCKezDccJcmqf8p5";
    function safeMint(address to) public {
        require(_tokenIdCounter.current() <= MAX, "exceed");
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

创一个 Alchemy 账户，选择 Sepolia 测试网
https://dashboard.alchemy.com/
Sepolia 水龙头 https://sepoliafaucet.com/):
在 MetaMask 中添加 Alchemy 节点
编译并开启优化
部署
在测试 OpenSea 上查看 https://testnets.opensea.io/