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Is there a way a smart contract can automatically generate tokenURI using the tokenIDs of erc721 tokens, if we dont want to use other methods. I am a newbie so need some guidance.

mzaidi
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1 Answers1

2

Yes, it is possible as you have the functions _mint() & _setTokenURI().

Following is a simple example, which is intended to do the same:

Solidity

// contracts/GameItem.sol
// SPDX-License-Identifier: MIT
pragma solidity <0.8.0;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/utils/Counters.sol";


contract GameItem is ERC721 {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;


string private tempURI;

constructor(
    string memory name,
    string memory symbol,
    string memory _tempURI
) ERC721(name, symbol) {
    tempURI = _tempURI;
}

function awardItem(address player) public returns (uint256) {
    _tokenIds.increment();

    uint256 newItemId = _tokenIds.current();
    _mint(player, newItemId);
    _setTokenURI(
        newItemId,
        string(abi.encodePacked(tempURI, uintToString(newItemId)))
    );

    return newItemId;
}

function uintToString(uint256 v) internal pure returns (string memory str) {
    uint256 maxlength = 100;
    bytes memory reversed = new bytes(maxlength);
    uint256 i = 0;
    while (v != 0) {
        uint256 remainder = v % 10;
        v = v / 10;
        reversed[i++] = bytes1(uint8(48 + remainder));
    }
    bytes memory s = new bytes(i);
    for (uint256 j = 0; j &lt; i; j++) {
        s[j] = reversed[i - 1 - j];
    }
    str = string(s);
}



}

Truffle test

const GameItem = artifacts.require("GameItem");

contract("Redroad", async (addresses) => {
  const [admin, _] = addresses;


it("works correctly.", async () => {
    let id = [];
    const gItem = await GameItem.new(
      "Invincible Collectible",
      "ICB",
      "http://www.myserver.com/tokenId="
    );


await gItem.awardItem(admin);
await gItem.awardItem(admin);

console.log(await gItem.tokenURI(&quot;1&quot;));
console.log(await gItem.tokenURI(&quot;2&quot;));



});
});

Following is the output for the truffle test:

 Contract: GameItem
http://www.myserver.com/tokenId=1
http://www.myserver.com/tokenId=2
    ✓ works correctly. (229ms)

References take from:

Anupam
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