ERC721 (NFT) - skka3134

用 Wizard 開發 contract
https://docs.openzeppelin.com/contracts/4.x/wizard
Mintable : mint nft
Auto increment Ids : id 自動增持
Burnable : 銷毀 nft
Pausable : 暫停 nft 轉移
Enumerable : 查看總發行量
URI storage : nft 的 uri
Ownable: 所有權控制，一個管理員
Roles: 所有權控制，多個管理員
Transparent: 透明代理
UUPS: 代理合約解決可衝突問題

// 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);
    }

定義一個最大发行量

    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);
    }

上傳元數據到 ipfs
https://console.filebase.com/
元數據的格式是 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. 修改代碼

    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);
    }

創建一個 alchemy 賬戶，選擇 Sepolia 測試網
https://dashboard.alchemy.com/
Sepolia 水龍頭 https://sepoliafaucet.com/):
在 metamask 中添加 alchemy 節點
編譯並開啟優化
部署
在 test opensea 上查看 https://testnets.opensea.io/