OpenZeppelin Issues – tokenId (uint256) Not Returning Correctly

openzeppelinreturndatauint256

In my tokenURI function, I have it setup to return the tokenId that is being called for, but when I run the method I get a symbol.

function tokenURI(uint256 _tokenId) public view virtual override returns (string memory) {
    require(_exists(_tokenId), "ERC721Metadata: URI query for nonexistent token");
    return string(abi.encodePacked(_baseURI(), "/", _tokenId, ".json"));

Here is the response I get when I call this function in Etherscan.

Is it not possible to return tokenId as a uint256 off chain?

Best Answer

The problem is that abi.encodePacked() encodes uint256 as a raw bytes sequence. In order to make it output /1234.json you have to convert an uint256 to an decimal string.

For example using uint2str from this question Conversion of uint to string it will look like this:

return string(
    abi.encodePacked(_baseURI(), 
        "/",
        uint2str(_tokenId),
        ".json"));

Related Solutions

Bytes32 Uint256 – Converting Between Bytes32 and Uint256

Assuming

genes.test.call(0x000063169218f348dc640d171b000208934b5a90189038cb3084624a50f7316c)

is JavaScript, your problem is probably that the parameter is getting interpreted as a JavaScript number, which does not have enough precision to handle numbers as grand as the one you are using. The solidity call therefore gets fed a less precise number, which it correctly casts to bytes32 and returns.

Try quoting the parameter, eg

genes.test.call("0x000063169218f348dc640d171b000208934b5a90189038cb3084624a50f7316c")

Alternatively you could pass a BN or BigNumber instance, eg

genes.test.call(new BigNumber("0x000063169218f348dc640d171b000208934b5a90189038cb3084624a50f7316c"))

The exact syntax you need varies a little bit depending on the web3.js versions and BigNumber / BN.js libraries you're using, but since native JavaScript numbers can't handle the full 256 bits you always need to handle them either as BigNumber/BN objects or as strings of hex beginning with "0x".

[Ethereum] converting uint256 to string

oraclize helped

 pragma solidity ^0.5.3;

        uint public degrees= 40;

        function getString() public view returns(string memory){
                string memory a = "today is ";
                string memory b = uint2str(degrees);
                string memory c = "degrees outside";
                string memory sentence = string(abi.encodePacked(a, b, c));
                return sentence;
        }

Best Answer

Related Solutions

Bytes32 Uint256 – Converting Between Bytes32 and Uint256

[Ethereum] converting uint256 to string

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