ERC721TGNT (NFTs for Token Gating, Non-Transferable)

ERC721 Non-Transferable Implementation, focused on saving gas for Token Gating

Using owner Address as TokenId

The intent of this implementation is to save as much gas as possible by trimming down on storage and evm instructions from the stardard implementations (being OpenZeppelin's the most widely used).

The use of common implementations depend on storing data for owner, id, approved and (multiple) approvedForAll, and using this for common tokenGating wastes a lot of gas on deploying contracts and more importantly minting, which wastes users gas.

Since the objective of token gating is allowing access of an address by checking a token ownership, several use cases don't need this access being exchanged on secondary markets. By removing these transfers, there's no need for approvals or aperators, allowing us to improve gas use on the smart contract thus making deployment, minting and burning far more efficient.

This implementation aims to provide a way for users and developers to take advantage of this and saving gas by inheriting it.

This project was developed using the Foundry smart contract development toolchain.

Installing

npm

If you use npm, you can install by running:

npm i @7i7o/tokengate

Foundry

If you are using Foundry (or Forge)just run:

forge install 7i7o/TokenGate

and add a line in your remappings.txt file (it should sit on your main project folder) with:

@7i7o/tokengate=lib/TokenGate/

Usage

Now you can import it in your solidity files like this:

import "@7i7o/tokengate/src/ERC721TGNT.sol";

To inherit this, you need to implement the contructor on your contract and pass a Name and a Symbol for your NFTs, like this:

contract Contract is ERC721TGNT {

    constructor() ERC721TGNT("Name", "Symbol") {}

}

Dev Instructions

To tinker with the implementation, you only need to fork this repo and start hacking.

To build (compile) you can run:

forge build

to build, run:

forge test

Gas Comparison

To have a estimate of gas savings for users and deployers, i ran basic tests deploying a basic contract that inherited OpenZeppelin's ERC721 and another set that inherited ERC721TGNT, both exposing basic _safeMint functionality.

I ran one test for creating a new contract, and another to create the contract and mint 1 token (to measure only minting gas).

The results of gas spent in each test for each contract can be seen in the table below

| Function | TGNT | OpenZeppelin | % Gas Saved by TGNT | | ------------- |--------------:| -------------:|---------------------:| | deploy | 649500 | 1168364 | 44.41% | | safeMint | 26930 | 49462 | 45.55% |

That's roughly 45% gas saving on both deploy and mint.

MIT License

Copyright (c) 2022 7i7o