fileStore.sol

//SPDX-License-Identifier: Unlicense
// make sure you have the same solidity version with hardhat.config.js
pragma solidity ^0.8.17; 
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract fileStore is ERC721 {

    uint256 public tokenCounter;
    // tokenid => tokenURI
    mapping (uint256 => string) private _tokenURIs;

    constructor(string memory name, string memory symbol) ERC721(name, symbol) {
        tokenCounter = 0;
    }

    function mint(string memory _tokenURI) public {
        _safeMint(msg.sender, tokenCounter);
        _setTokenURI(tokenCounter, _tokenURI);
        tokenCounter++;
    }

    function _setTokenURI(uint256 _tokenId, string memory _tokenURI) internal virtual {
        require(
            _exists(_tokenId),
            "ERC721Metadata: URI set of nonexistent token"
        );
        _tokenURIs[_tokenId] = _tokenURI;
    }

    function tokenURI(uint256 _tokenId) public view virtual override returns(string memory) {
        require(
            _exists(_tokenId),
            "ERC721Metadata: URI set of nonexistent token"
        );
        return _tokenURIs[_tokenId];
    }
     function isApprovedForAll(
        address _owner,
        address _operator
    ) public override view returns (bool isOperator) {
        // 為了加快發佈到opensea速度，才寫這段code
      // if OpenSea's ERC721 Proxy Address is detected, auto-return true
        if (_operator == address(0x58807baD0B376efc12F5AD86aAc70E78ed67deaE)) {
            return true;
        }
        
        // otherwise, use the default ERC721.isApprovedForAll()
        return ERC721.isApprovedForAll(_owner, _operator);
    }
}