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Hook Modules

Overview​

Hook modules enable custom logic to be executed at specific points in the transaction lifecycle. These hooks can trigger additional actions either before or after a transaction is processed.

  • Module Type ID: MODULE_TYPE_HOOK
  • Interface: Implements IHook.

Interface​

interface IHook is IModule {
    function preCheck(
        address msgSender,
        uint256 msgValue,
        bytes calldata msgData
    ) external returns (bytes memory hookData);

    function postCheck(bytes calldata hookData) external;
}

Sample Hook Modules​

  • GasRefund Hook: Automatically refunds gas costs to the user after a transaction is processed.
  • Logging Hook: Logs transaction details to an off-chain service for record-keeping purposes.

Installation and Uninstallation​

All modules follow a similar installation and uninstallation process. When a module is installed or uninstalled, the corresponding onInstall or onUninstall functions are called with any necessary initialization or cleanup data.

Module Type Verification​

Modules implement the isModuleType function to verify their type (Validator, Executor, Hook, Fallback), as specified by their moduleTypeId.