Auth

source code // tests

Auth implements a multi owner authorization pattern.

An owner is known as a ward of the contract. Wards can make other users wards by calling rely(address usr), or they can demote other wards by calling deny(address usr).

A contract that inherits from Auth will have the auth modifier available, which will revert if the caller is not a ward.

The constructor of Auth takes an address that will be made the initial ward.

Properties

• authed methods can only be called by wards
• wards can only be added and removed by other wards
• all changes to ward status are logged

Reference

Data

• mapping (address => bool): wards status for every ethereum address

Methods

rely(address usr):

• makes usr a ward
• logs a Rely event

deny(address usr):

• removes usr as a ward
• logs a Deny event

Events

• Rely(address usr): usr is now a ward
• Deny(address usr): usr is no longer a ward

Example

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.6;

import {Auth} from "dappsys-v2/auth.sol";

contract Set is Auth {
    uint public value;

    // note that we must call the constructor of Auth to specify the initial ward
    constructor(uint v) Auth(msg.sender) {
        value = v;
    }

    function set(uint v) external auth {
        value = v;
    }
}

contract UseSet {
    function go() external {
        Set set = new Set(10);

        // we are a ward here since we deployed the contract
        require(set.wards(address(this)));

        // since we are a ward we can call `set`
        set.set(11);
        require(set.value() == 11);

        // make vitalik a ward
        set.rely(0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B);
        // revoke our authority
        set.deny(address(this));

        // this fails now since we are no longer a ward
        set.set(12);
    }
}