Created
August 14, 2021 21:48
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Versioned NFT
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| //SPDX-License-Identifier: Unlicense | |
| pragma solidity ^0.8.0; | |
| import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol"; | |
| import "@openzeppelin/contracts/utils/Counters.sol"; | |
| contract Versioned is ERC721URIStorage { | |
| using Counters for Counters.Counter; | |
| using Strings for uint256; | |
| Counters.Counter private _tokenIds; | |
| // mapping of keccak256(tokenId, tokenVersion) to version URIs. | |
| mapping(bytes32 => string) private _tokenVersionURIs; | |
| // mapping of tokenId to array of version names. | |
| mapping(uint256 => string[]) private _tokenVersionNames; | |
| // Published event is emitted when a new token version is published. | |
| event Published(address indexed _from, uint256 indexed _tokenId, string _tokenVersion, string _tokenURI); | |
| constructor() ERC721("Versioned", "V") {} | |
| /** | |
| * Returns the total number of versions for the token with the given tokenId. | |
| */ | |
| function versionCount(uint256 tokenId) public view returns (uint256) { | |
| require(_exists(tokenId), "token does not exist"); | |
| return _tokenVersionNames[tokenId].length; | |
| } | |
| /** | |
| * Returns the version name of the token with the given tokenId at the given index. | |
| */ | |
| function versionNameByIndex(uint256 tokenId, uint256 index) public view returns (string memory) { | |
| require(index < _tokenVersionNames[tokenId].length, "index out of bounds"); | |
| return _tokenVersionNames[tokenId][index]; | |
| } | |
| /** | |
| * Returns the URI of the token with the given tokenId at the given version. | |
| */ | |
| function versionURI(uint256 tokenId, string memory tokenVersion) public view returns (string memory) { | |
| require(_exists(tokenId), "token does not exist"); | |
| bytes32 selector = keccak256(abi.encodePacked(tokenId, tokenVersion)); | |
| return _tokenVersionURIs[selector]; | |
| } | |
| /** | |
| * Create a new versioned token with an initial version and URI. | |
| */ | |
| function create(string memory tokenVersion, string memory tokenURI) public returns (uint256) { | |
| require(bytes(tokenVersion).length > 0, "invalid token version"); | |
| require(bytes(tokenURI).length > 0, "invalid token URI"); | |
| _tokenIds.increment(); | |
| uint256 tokenId = _tokenIds.current(); | |
| _mint(msg.sender, tokenId); | |
| publish(tokenId, tokenVersion, tokenURI); | |
| return tokenId; | |
| } | |
| /** | |
| * Publish a new version of an existing token. | |
| */ | |
| function publish(uint256 tokenId, string memory tokenVersion, string memory tokenURI) public { | |
| require(_isApprovedOrOwner(msg.sender, tokenId), "publish caller is not owner nor approved"); | |
| require(bytes(tokenVersion).length > 0, "invalid token version"); | |
| require(bytes(tokenURI).length > 0, "invalid token URI"); | |
| bytes32 selector = keccak256(abi.encodePacked(tokenId, tokenVersion)); | |
| require(bytes(_tokenVersionURIs[selector]).length == 0, "version already exists"); | |
| _tokenVersionURIs[selector] = tokenURI; | |
| _tokenVersionNames[tokenId].push(tokenVersion); | |
| _setTokenURI(tokenId, tokenURI); | |
| emit Published(msg.sender, tokenId, tokenVersion, tokenURI); | |
| } | |
| } |
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