Simple way to concatenate tokenID to tokenURI-CodePudding

I am doing a project for my Honours year at the University of Cape Town using solidity and openzeppelin for my NFTs. I have uploaded a folder of json/png for the metadata. I need to now use the tokenID .json to set the tokens correct uri when minting them. Below is the simple contract:

    //SPDX-License-Identifier: MIT
pragma solidity ^0.8;
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
contract ImpactCollection is ERC721URIStorage {
    uint256 public tokenCounter;
    constructor () ERC721 ("Impact Tokens", "COLLECTION_TICKER"){
        tokenCounter = 0;
    }
    function concatenate(string memory a,uint256 memory b,string memory c) public pure returns (string memory){
        return string(abi.encodePacked(a,b,c));
    }

    function createCollectible() public returns (uint256) {
        uint256 newItemId = tokenCounter;
        string urinumber = string(abi.encodePacked(newItemId.toString()))
        tokenURI = "https://ipfs.io/ipfs/QmQh54Rb8ZFY33P9bWUzgonRvA7XeChVWaAWG3nMqQ19xW/"   urinumber   ".json";
        _safeMint(msg.sender, newItemId);
        _setTokenURI(newItemId, tokenURI);
        tokenCounter = tokenCounter   1;
        return newItemId;
    }

}

I have the folder url above and i just need to add the token id and then add a .json. My C# brain says: "ipfsurl" newItemId.toString() ".json";

What is the remix (solidity) equivalent?

CodePudding user response：

From solidity version 0.8.12 you can use string.concat(s1,s2) for concatenate the strings. I adjusted and put some notes in your smart contract code:

//SPDX-License-Identifier: MIT
pragma solidity ^0.8;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/utils/Strings.sol";

contract ImpactCollection is ERC721URIStorage {
  uint256 public tokenCounter;
  using Strings for *;
  
  constructor () ERC721 ("Impact Tokens", "COLLECTION_TICKER"){
    tokenCounter = 0;
  }

  function concatenate(string memory a,uint256 b,string memory c) public pure returns (string memory){
    return string(abi.encodePacked(a,b,c));
  }

  function createCollectible() public returns (uint256) {
    uint256 newItemId = tokenCounter;
    // NOTE: Use Strings.toString for convert a uint to string datatype
    string memory urinumber = Strings.toString(newItemId);
    // NOTE: I declared a new variable for contain token URI
    string memory tokenURI = "https://ipfs.io/ipfs/QmQh54Rb8ZFY33P9bWUzgonRvA7XeChVWaAWG3nMqQ19xW/";
    // NOTE: I declare a new variable for contain tokenURI concatenated    
    string memory fullTokenURI = string.concat("https://ipfs.io/ipfs/QmQh54Rb8ZFY33P9bWUzgonRvA7XeChVWaAWG3nMqQ19xW/", urinumber, ".json");
    _safeMint(msg.sender, newItemId);
    _setTokenURI(newItemId, tokenURI);
    tokenCounter = tokenCounter   1;
    return newItemId;
  }

}

CodePudding user response：

This will work!

_setTokenURI(newItemId, string(abi.encodePacked(_uri, '/', newItemId.toString(), '.json')));