EIP Draft : mint arbitrary number of tokens(ERC-721) via EIP-2309

sciNFTist.eth · November 3, 2022, 2:08pm

EIP Draft : ERC721FancyMint

eip: eip-draft_ERC721FancyMint
title: ERC721FancyMint
author: scinftist.eth (shypink@protonmail.com)
status: draft not submitted
type: ERC
created: 2022-11-3
requires (*optional): <EIP 165 721 2309>

Abstract

This standard proposes another implementation to IERC721 Non-Fungible Tokens (NFTs) to eliminate minting fee of fixed length collection.

Motivation

As of today there is 3 way to create a collection.

Minting the tokens ahead so people can see it and find it trough market places. this includes minting fee for creators!
create a contract and people mint the tokens, with first come first served strategy.
people cant see the Tokens before hand. and users don’t know what they get.
using just in time minting or Lazy minting. that is only accessible trough one platform.
this limits the creators to one platform.

this implementation is like creator minted arbitrary number of tokens before hand without using gas fee on minting process.

benefits:

no minting fee, any number of token mint in constructor with O(1) execution.
user can view the tokens before purchasing.
tokens are accessible trough all Ethereum platforms.

caveat

any number of tokens should be minted at deployment time, an there is no further _mint() or _safeMint() function available.
this token does not support _burn() function.

Specification

maxSupply is desired number of token that we want to mint
preOwner is the address that all tokens will be transferred to

Interface

this interface is needed for Enumerable extension (IERC721Enumerable) of this contract.

// get the preOwner of a tokens
function preOwner() public view returns(address);


// get the maxSupply of a token
function maxSupply() public view returns(uint256);

The maxSupply_ MUST NOT be 0.
The preOwnwer_ MUST NOT be 0x0 (i.e. zero address).

Implementation

proposed changes to
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)
for full Implementation see Reference Implementation.

//proposed changes

contract ERC721FancyMint is
    Context,
    ERC165,
    IERC721,
    IERC721Metadata,
    IERC2309
{
     *@dev my proposal
     */

    //max
    uint256 private _maxSupply;
    //NFT owner
    address private _preOwner;

    
    constructor(
        string memory name_,
        string memory symbol_,
        uint256 maxSupply_,
        address preOwner_
    ) {

        require(preOwner_ != address(0), "preOwner can NOT be address(0)");
        require(0 < maxSupply_, "maxSupply_ should not be zero!");
        _name = name_;
        _symbol = symbol_;

        //@dev my proposal

        _maxSupply = maxSupply_;
        _preOwner = preOwner_;
        // blance of preOwner
        _balances[preOwner_] = maxSupply_;

        // see eip-2309 examples for batch creation
        emit ConsecutiveTransfer(0, maxSupply_ - 1, address(0), preOwner_);
    }

    function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
        address owner = _owners[tokenId];
        if (owner == address(0) && (tokenId < _maxSupply)) {
            return _preOwner;
        }
        return owner;
    }


    //-----------------------
    function maxSupply() public view returns (uint256) {
        return _maxSupply;
    }

    function preOwner() public view returns (address) {
        return _preOwner;
    }

// and _mint() _safeMint() _burn() are removed from openZeppelin ERC721 Implementation V4.7.0



}

Rationale

since EIP-2309 make the creation of arbitrary number of Tokens possible.

this changes make this possible.

since the default value of _balances mapping is 0.

At creation time we assigned maxSupply to _balances[preOwner] from IERC721 interface point of view, preOwner has maxSupply number of tokens as it’s balance.
this contract consider tokenIds range from 0 to ( maxSupply - 1 ).
to handle owners addresses, _ownerOf(tokenId) has been changed, If the _owners[tokenId] is the defualt value 0x0 (i.e address(0) ) & the tokenId is smaller than maxSupply it returns preOwner. else it returns the value that is stored in mapping.

these changes wont affect the functionality of IERC721.

the interface is consist of two public functions, they are necessary for Enumerable (IERC721Enumerable) extension of this standard.

/**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _ownerOf(tokenId);
        require(owner != address(0), "ERC721: invalid token ID");
        return owner;
    }



    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _ownerOf(tokenId) != address(0);
    }

for values greater equal than maxSupply, _ownerOf(tokenId) will alweys return 0x0 i.e address(0). therefore token _exist() is false for these values.

for values smaller than maxSupply, if _owners[tokenId] is not 0x0 address(0) the owner is the returned value.

since there is no other function that uses _ownerOf(tokenId), the behavior of the contract is the same as ERC721 implementation of ERC721 by OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)

these function that where omitted

_burn(uint256 tokenId)
_mint(address to, uint256 tokenId)
_safeMint(address to, uint256 tokenId, bytes memory data)
_safeMint(address to, uint256 tokenId)

Backwards Compatibility

this standard is fully compatible with all IERC721.

since this implementation does not support any _burn function event Transfer() to 0x0 (i.e. address(0) ) will never happen.
Transfer() event from account from address 0x0 (i.e. address(0) ) won’t happen because there will be only 1 minting event that happens in constructor() and token creation emits via ConsecutiveTransfer() event

ConsecutiveTransfer(0, maxSupply_ - 1, address(0), preOwner_)

Test Cases

Test cases were Implemented in PR:
…/assets/eip-draft_ERC721FancyMint/testCase.sol

some of the tokens has been listed for sale for testing

Test Case 1 on goerli testnet with 5000 tokens

Test case 1 on OpenSea with 5000 tokens

some of the tokens has been listed for sale for testing but this test case includes 6000 token but opensea fails to show some tokens (tokenId 5000 to 5999), i think it’s due to bad implementation of EIP-2309, I’m getting in touch with them, and I wish to hear about your thoughts on this matter.

see EIP-2309 examples

“Batch token creation:
emit ConsecutiveTransfer(1, 100000, address(0), to Address);”

Test Case 2 on goerli testnet with 6000 tokens

Test case 2 on OpenSea with 6000 tokens

Reference Implementation

Test cases where Implemented in PR:
…/assets/eip-draft_ERC721FancyMint/ERC721FancyMint.sol

Security Considerations

This EIP standard can completely protect the rights of the owner, the owner can change the NFT user and use period at any time.

but if some how user burns a token, the owner of token will be set to 0x0 (i.e. address(0) ) the token won’t be destroyed and it will assigned to preOwner. I don’t know if it occurs or not, since the _burn() function is removed and _trandfer() function has require that prevent transfer _to address(0) 0x0. I wish to hear from you if you can assure me on this.

require(to != address(0), "ERC721: transfer to the zero address");

Copyright

Copyright and related rights waived via CC0.

xinbenlv · January 4, 2023, 5:45pm

Thanks for the draft. Congrats on your first drat.

Some technical feedback

I’ve not figure out a strong rationale why an extra function preOwner is necessary when you could just do

contract FancyMint {
  mapping (uint256 => address) _owners;
  address _preOwner; // initalize in the constructor or set somewhere, or just use the owner from IOwnable
  function ownerOf(uint256 tokenId) view return(address) {
    if (tokenId < _maxSupply {
      return _owners[tokenId] ? _owners[tokenId] : _preOwner;
    }
  }
}

sciNFTist.eth · January 4, 2023, 7:02pm

Thank you for your time and the energy that you gave me.
also thanks for the code it’s elegant.
originally I was thinking about of Enumerable batch minting

ERC721Enumerable /* is ERC721 */ {
    function totalSupply() external view returns (uint256);
    function tokenByIndex(uint256 _index) external view returns (uint256);
    function tokenOfOwnerByIndex(address _owner, uint256 _index) external view returns (uint256);
}

and there was few more steps needed to make this IERC721Enumerable compatible.

function totalSupply() public view virtual override returns (uint256) {
        return ERC721FancyMint.maxSupply();
    }

/**
     * @dev handling tokens index virtualy
     */
    function tokenByIndex(uint256 index)
        public
        view
        virtual
        override
        returns (uint256)
    {
        require(
            index < ERC721FancyMintEnum.totalSupply(),
            "ERC721Enumerable: global index out of bounds"
        );
        return index;
    }

function tokenOfOwnerByIndex(address owner, uint256 index)
        public
        view
        virtual
        override
        returns (uint256)
    {
     
        address _preOwner = ERC721FancyMint.preOwner();

        require(
            index < ERC721FancyMint.balanceOf(owner),
            "ERC721Enumerable: owner index out of bounds"
        );
        if (_preOwner == owner) {
            return preIndex(index);
        } else {
            return _ownedTokens[owner][index];
        }
    }

function _beforeTokenTransfer( address from, address to, uint256 tokenId ) needed some more tweaks with some new functions _addTokenToPreOwner() , _removeTokenFromPreOwner()
the file on the github ERC721FancyMintEnumRef.sol

If you find the time to check this too, I’ll be grateful.

nathanglb · August 21, 2023, 5:14pm

I put out an article on this with some sample code in 2022. Feel free to have a look.

I invented this at Nifty Gateway and they do this at scale (since April 2022). Feel free to check out their official implementation at:

https://etherscan.io/address/0xee2c03ced8b6755e8d76ab144677f5f350203cab#code

sciNFTist.eth · August 23, 2023, 7:58pm

I read your article it was great and I really liked this part

struct CollectionStatus {        
    bool isMinted;
    uint88 amountCreated;
    address defaultOwner;
}

It’s great to find a likeminded friend

nathanglb · September 8, 2023, 3:35am

Thanks! Good luck with this!