Gates

Gates are small contracts with simple checks that can be used on contracts. Similar to OpenZeppelin’s Ownable with the modifier onlyOwner.

TokenGate

TokenGate lets us check the balance of ERC20 or ERC721 tokens.


modifier onlyToken(account, token, amount)

Example


contract GatedRegistryWithMerkleClaim is Allocator, Registry, TokenGate, MerkleClaim {
    address private alloToken;
    address private guildNFT;
 
    constructor(address _alloToken, address _guildNFT) {
        alloToken = _alloToken;
        guildNFT = _guildNFT;
    }
 
    // Only holders of 1 Guild NFT can register projects
    function register(
        address project,
        string memory metadataURI, // Metadata contain Application Details
        bytes memory data
    ) public override onlyToken(msg.sender, guildNFT, 1) {
        _register(project, metadataURI, data);
    }
 
    // Only holders of 10 ALLO tokens can approve projects
    function approve(
        address project,
        string memory metadataURI, // Metadata contains Application Review
        bytes memory data
    ) public override onlyToken(msg.sender, alloToken, 10 ** 18) {
        _approve(project, metadataURI, data);
    }
 
    // Only Owner can update Merkle
    function setMerkle(bytes32 _root) public override onlyOwner {
      _setMerkle(_root);
    }
 
    // This is the same function as in MerkleClaim added here for clarity
    function claim(bytes32[] memory proof, address token, address recipient, uint256 amount) public override {
      if (_verify(proof, token, recipient, amount)) {
        IERC20(token).transfer(recipient, amount);
        emit Claim(recipient, amount, token);
      }
    }
}

EASGate

Check if an account has an attestation for a specific schemaUID and attester. Can be used for example for OP Badgeholders or only approved projects can register projects.


modifier onlyEAS(account, schemaUID, attester)


contract OptimismRetroFunding is Allocator, EASGate, Registry {
  // Only OP Badgeholders can call
  function allocate() public overide onlyEAS(msg.sender, badgeholderSchemaUID, approvedAttester) {
    _allocate(recipient, token, amount);
  }
 
  function register(address project) onlyEAS(project, approvedSchemaUID, approvedAttester) {
    _register(recipient, metadataURI);
  }
}