ERC721 (NFT) - skka3134

ウィザードを使って契約を開発
https://docs.openzeppelin.com/contracts/4.x/wizard
Mintable : NFT をミント
Auto increment Ids : id 自動増加
Burnable : NFT を焼却
Pausable : NFT の転送を一時停止
Enumerable : 総発行量を確認
URI storage : NFT の URI
Ownable: 所有権管理、1 人の管理者
Roles: 所有権管理、複数の管理者
Transparent: 透明なプロキシ
UUPS: プロキシ契約の衝突問題を解決

// 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);
    }

    // 以下の関数はSolidityによって必要なオーバーライドです。

    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/
safeMint の onlyOwner を削除し、誰でもミントできるようにする

    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);
    }

最大発行量を定義する

    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);
    }

メタデータを IPFS にアップロード
https://console.filebase.com/
メタデータの形式は JSON

{
    "description": "ドラゴン", 
    "external_url": "https://openseacreatures.io/3", 
    "image": "https://ipfs.filebase.io/ipfs/QmewcWVm6zmnCEwDzZSanrzdFNdzCF8X4Tfo5Qi87Qdhrf", 
    "name": "ドラゴン",
    "attributes": [
      {
        "trait_type": "ベース", 
        "value": "ヒトデ"
      }, 
      {
        "trait_type": "目", 
        "value": "大きい"
      }, 
      {
        "trait_type": "口", 
        "value": "驚いた"
      }, 
      {
        "trait_type": "レベル", 
        "value": 5
      }   
    ]
  }

7. コードを修正

    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);
    }

Alchemy アカウントを作成し、Sepolia テストネットを選択
https://dashboard.alchemy.com/
Sepolia ファ aucet https://sepoliafaucet.com/):
MetaMask に Alchemy ノードを追加
コンパイルして最適化を有効にする
デプロイ
テスト OpenSea で確認する https://testnets.opensea.io/