Create a Module

Create a custom module when the standard library does not cover your validation logic.

If a standard-library module already fits your need, you can skip this page and just register or reuse that module.

Contract base

Custom modules inherit AbstractModuleV2:

import { AbstractModuleV2 } from "@verax-attestation-registry/verax-contracts/contracts/abstracts/AbstractModuleV2.sol";

Then implement:

function run(
  AttestationPayload calldata attestationPayload,
  bytes calldata validationPayload,
  address initialCaller,
  uint256 value,
  address attester,
  address portal,
  OperationType operationType
) public virtual;

run(...) should revert when validation fails.

Minimal example

// SPDX-License-Identifier: MIT
pragma solidity 0.8.21;

import { AbstractModuleV2 } from "@verax-attestation-registry/verax-contracts/contracts/abstracts/AbstractModuleV2.sol";
import { AttestationPayload } from "@verax-attestation-registry/verax-contracts/contracts/types/Structs.sol";
import { OperationType } from "@verax-attestation-registry/verax-contracts/contracts/types/Enums.sol";

contract ExampleModule is AbstractModuleV2 {
  error InsufficientFee();

  function run(
    AttestationPayload calldata,
    bytes calldata,
    address,
    uint256 value,
    address,
    address,
    OperationType
  ) public pure override {
    if (value < 0.001 ether) revert InsufficientFee();
  }
}

Important implementation notes

• Inheriting AbstractModuleV2 already gives you ERC-165 support for registration checks.
• validationPayload is where you pass signatures, proofs, or any module-specific data.
• operationType lets you distinguish attest vs bulk attest vs replace vs bulk replace.
• If you rely on msg.value, remember that only one module in a chain should interpret it.
• Bulk module execution currently passes 0 as value in ModuleRegistry.bulkRunModulesV2(...).

warning

If your module depends on fees or any other payable behavior, remember that bulk module execution currently passes 0 as value.

Next step

Once deployed, register the module in ModuleRegistry.

See Register a Module.