百亿项目 Alchemy Road to Web3 第五周 NFT 获取教程

2022-08-16 20:29

Greta

2022-08-16 20:29

Greta

2022-08-16 20:29

来源链接

订阅此专栏

收藏此文章

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。

手把手第五周教程开始：使用 Chainlink 预言机构建基于市场数据变化的动态 NFT

什么是动态 NFT？这一课很有趣。

NFT 会变化，就像下面一样，我们开始吧！

step1 领取测试币

1.小狐狸钱包调整到 rinkey 测试网，进 faucets.chain.link ，领取测试币。

step2 编译合约

1.进入remix.ethereum.org ,如图新建一个工作台，随意命名。

2.右键删除 contract 下面的三个文件。

3.在 contracts 下面新建名为 Bull&Bear.sol 的文件夹。

4.将下面的代码复制粘贴进来。

// SPDX-License-Identifier: GPL-3.0pragma solidity ^0.8.4;import "@openzeppelin/contracts/token/ERC721/ERC721.sol";import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";import "@openzeppelin/contracts/access/Ownable.sol";import "@openzeppelin/contracts/utils/Counters.sol";import "@openzeppelin/contracts/utils/Strings.sol";// Chainlink Importsimport "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";// This import includes functions from both ./KeeperBase.sol and// ./interfaces/KeeperCompatibleInterface.solimport "@chainlink/contracts/src/v0.8/KeeperCompatible.sol";import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";// Dev imports. This only works on a local dev network// and will not work on any test or main livenets.import "hardhat/console.sol";contract BullBear is ERC721, ERC721Enumerable, ERC721URIStorage, Ownable, VRFConsumerBaseV2, KeeperCompatibleInterface  {    using Counters for Counters.Counter;    Counters.Counter private _tokenIdCounter;    uint public interval;    uint public lastTimeStamp;    AggregatorV3Interface public priceFeed;    int256 public currentPrice;    // IPFS URIs for the dynamic nft graphics/metadata.    // NOTE: These connect to my IPFS Companion node.    // You should upload the contents of the /ipfs folder to your own node for development.    string[] bullUrisIpfs = [        "https://ipfs.io/ipfs/QmRXyfi3oNZCubDxiVFre3kLZ8XeGt6pQsnAQRZ7akhSNs?filename=gamer_bull.json",        "https://ipfs.io/ipfs/QmRJVFeMrtYS2CUVUM2cHJpBV5aX2xurpnsfZxLTTQbiD3?filename=party_bull.json",        "https://ipfs.io/ipfs/QmdcURmN1kEEtKgnbkVJJ8hrmsSWHpZvLkRgsKKoiWvW9g?filename=simple_bull.json"    ];    string[] bearUrisIpfs = [        "https://ipfs.io/ipfs/Qmdx9Hx7FCDZGExyjLR6vYcnutUR8KhBZBnZfAPHiUommN?filename=beanie_bear.json",        "https://ipfs.io/ipfs/QmTVLyTSuiKGUEmb88BgXG3qNC8YgpHZiFbjHrXKH3QHEu?filename=coolio_bear.json",        "https://ipfs.io/ipfs/QmbKhBXVWmwrYsTPFYfroR2N7NAekAMxHUVg2CWks7i9qj?filename=simple_bear.json"    ];    // random    VRFCoordinatorV2Interface COORDINATOR;    // Your subscription ID.    uint64 s_subscriptionId;    // Goerli coordinator. For other networks,    // see https://docs.chain.link/docs/vrf-contracts/#configurations    address vrfCoordinator = 0x6168499c0cFfCaCD319c818142124B7A15E857ab;    // The gas lane to use, which specifies the maximum gas price to bump to.    // For a list of available gas lanes on each network,    // see https://docs.chain.link/docs/vrf-contracts/#configurations    bytes32 keyHash = 0xd89b2bf150e3b9e13446986e571fb9cab24b13cea0a43ea20a6049a85cc807cc;    // Depends on the number of requested values that you want sent to the    // fulfillRandomWords() function. Storing each word costs about 20,000 gas,    // so 100,000 is a safe default for this example contract. Test and adjust    // this limit based on the network that you select, the size of the request,    // and the processing of the callback request in the fulfillRandomWords()    // function.    uint32 callbackGasLimit = 100000;    // The default is 3, but you can set this higher.    uint16 requestConfirmations = 3;    // For this example, retrieve 2 random values in one request.    // Cannot exceed VRFCoordinatorV2.MAX_NUM_WORDS.    uint32 numWords =  2;    uint256[] public s_randomWords;    uint256 public s_requestId;    event TokensUpdated(string marketTrend);    constructor(uint updateInterval, address _priceFeed, uint64 subscriptionId) ERC721("Bull&Bear", "BBTK") VRFConsumerBaseV2(vrfCoordinator) {        interval = updateInterval;        lastTimeStamp = block.timestamp;        // https://rinkeby.etherscan.io/address/0xECe365B379E1dD183B20fc5f022230C044d51404        priceFeed = AggregatorV3Interface(_priceFeed);        currentPrice = getLatestPrice();        COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);        s_subscriptionId = subscriptionId;    }    function safeMint(address to) public {        // Current counter value will be the minted token's token ID.        uint256 tokenId = _tokenIdCounter.current();        // Increment it so next time it's correct when we call .current()        _tokenIdCounter.increment();        // Mint the token        _safeMint(to, tokenId);        // Default to a bull NFT        string memory defaultUri = bullUrisIpfs[s_randomWords[0]%3];        _setTokenURI(tokenId, defaultUri);        console.log(            "DONE!!! minted token ",            tokenId,            " and assigned token url: ",            defaultUri        );    }    function checkUpkeep(bytes calldata) external view override returns (bool upkeepNeeded, bytes memory /*performData*/){        upkeepNeeded = (block.timestamp - lastTimeStamp) > interval;    }    function performUpkeep(bytes calldata) external override{        if((block.timestamp - lastTimeStamp) > interval){            lastTimeStamp = block.timestamp;            int latestPrice = getLatestPrice();            if(latestPrice == currentPrice){                return;            }else if(latestPrice < currentPrice){                updateAllTokenUris("bears");            }else{                updateAllTokenUris("bull");            }            currentPrice = latestPrice;        }    }    function getLatestPrice() public view returns(int256){        (,        int price,        ,        ,) = priceFeed.latestRoundData();        return price;    }    function updateAllTokenUris(string memory trend) internal{        if(compareStrings("bears", trend)){            for(uint i=0; i< _tokenIdCounter.current(); i++){                _setTokenURI(i,bearUrisIpfs[s_randomWords[0]%3]);            }        }else {            for(uint i=0; i< _tokenIdCounter.current(); i++){                _setTokenURI(i,bullUrisIpfs[s_randomWords[0]%3]);            }        }        emit TokensUpdated(trend);    }    function setInterval(uint256 newInterval) public onlyOwner{        interval = newInterval;    }    function setPriceFeed(address newFeed) public onlyOwner{        priceFeed = AggregatorV3Interface(newFeed);    }    function compareStrings(string memory a, string memory b) internal pure returns (bool){        return keccak256(abi.encodePacked(a)) == keccak256(abi.encodePacked(b));    }    // The following functions are overrides required by Solidity.    function _beforeTokenTransfer(        address from,        address to,        uint256 tokenId    ) internal override(ERC721, ERC721Enumerable) {        super._beforeTokenTransfer(from, to, tokenId);    }    function _burn(uint256 tokenId)        internal        override(ERC721, ERC721URIStorage)    {        super._burn(tokenId);    }    function tokenURI(uint256 tokenId)        public        view        override(ERC721, ERC721URIStorage)        returns (string memory)    {        return super.tokenURI(tokenId);    }    function supportsInterface(bytes4 interfaceId)        public        view        override(ERC721, ERC721Enumerable)        returns (bool)    {        return super.supportsInterface(interfaceId);    }        // Assumes the subscription is funded sufficiently.    function requestRandomWords() external onlyOwner {        // Will revert if subscription is not set and funded.        s_requestId = COORDINATOR.requestRandomWords(        keyHash,        s_subscriptionId,        requestConfirmations,        callbackGasLimit,        numWords        );    }    function fulfillRandomWords(        uint256, /* requestId */        uint256[] memory randomWords    ) internal override {        s_randomWords = randomWords;    }}

5.点击左侧的编译器菜单，版本选 0.8.4，然后点击编译。