Solidity - Getting from Factory Pattern to Clone Factory Pattern

Question

Below is an example of a solidity contract that's a factory pattern native approach that's adding crew to the neb starship in the matrix.

What would be the Clone Factory version of this contract?

// SPDX-License-Identifier: MIT
pragma solidity >0.4.23 <0.9.0;

contract NebCrewFactory {

    //Creating an array of neb crew addresses
    NebCrew[] public NebCrewAddresses;

    function addNebCrew() public {

        //Creating a new crew object, you need to pay //for the deployment of this contract everytime - $$$$
        NebCrew nebCrewAddress = new NebCrew();

        //Adding the new crew to our list of crew addresses
        NebCrewAddresses.push(nebCrewAddress);
    }
}

contract NebCrew{

    address public crew;

    constructor() {
        crew = msg.sender;
    }

    function welcomeCrew() public pure returns (string memory _greeting) {
        return "Welcome to the truth...";
    }
}

score 2 · Accepted Answer · answered Mar 09 '22 at 14:54

The clone factory version I am showing uses the OpenZeppelin library here

// SPDX-License-Identifier: MIT
pragma solidity >0.4.23 <0.9.0;

import { Clones } from "@openzeppelin/contracts/proxy/Clones.sol";

contract NebCrewFactory {

    //Creating an array of neb crew addresses
    NebCrew[] public NebCrewAddresses;
    address public implementationAddress;
    function addNebCrew() public {

        //Creating a new crew object, you need to pay //for the deployment of this contract everytime - $$$$
        NebCrew nebCrewAddress = NewCrew(Clones.clone(implementationAddress));

        // since the clone create a proxy, the constructor is redundant and you have to use the initialize function
        nebCrewAddress.initialize(); 

        //Adding the new crew to our list of crew addresses
        NebCrewAddresses.push(nebCrewAddress);
    }
}

contract NebCrew{

    address public crew;

    initialize() {
        require(crew == address(0), "already initialized");
        crew = msg.sender;
    }

    function welcomeCrew() public pure returns (string memory _greeting) {
        return "Welcome to the truth...";
    }
}

Also unrelated but I thought to mention, it's better to use a map in the factory instead of an array if you can since it might cause a problem in the future

Solidity - Getting from Factory Pattern to Clone Factory Pattern

1 Answers1