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ERC20SignatureMint

import "@thirdweb-dev/contracts/extension/SignatureMintERC20.sol";

The SignatureMintERC20 smart contract is an extension meant for distributing ERC20 tokens.

The 'signature minting' mechanism in the SignatureMintERC20 extension uses EIP-712, and is a way for a contract admin to authorize an external party's request to mint tokens on the admin's contract. At a high level, this means you can authorize some external party to mint tokens on your contract and specify what exactly will be minted by that external party.

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Usage

The SignatureMintERC20 extension is an abstract contract, and expects you to implement the following functions by yourself:

NameTypeDescription
_canSignMintRequestinternal view virtualRuns on every attempt to mint tokens with signature on the contract. Returns whether the signer is authorized to issue a signature for minting.
mintWithSignatureexternal payableMints tokens according to the provided mint request.

This is an example smart contract demonstrating how to inherit from this extension and override the functions to add (optional) custom functionality.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
 
import "@thirdweb-dev/contracts/base/ERC20Base.sol";
import "@thirdweb-dev/contracts/extension/SignatureMintERC20.sol";
import "@thirdweb-dev/contracts/lib/CurrencyTransferLib.sol";
 
contract ERC20SignatureMint is ERC20Base, SignatureMintERC20 {
    /*//////////////////////////////////////////////////////////////
                            Constructor
    //////////////////////////////////////////////////////////////*/
 
    constructor(address _defaultAdmin, string memory _name, string memory _symbol)
        ERC20Base(_defaultAdmin, _name, _symbol)
    {}
 
    /// @dev Mints tokens according to the provided mint request.
    function mintWithSignature(
        MintRequest calldata _req,
        bytes calldata _signature
    ) external payable virtual returns (address signer) {
        require(_req.quantity > 0, "Minting zero tokens.");
 
        // Verify and process payload.
        signer = _processRequest(_req, _signature);
 
        address receiver = _req.to;
 
        // Collect price
        _collectPriceOnClaim(
            _req.primarySaleRecipient,
            _req.quantity,
            _req.currency,
            _req.pricePerToken
        );
 
        // Mint tokens.
        _mint(receiver, _req.quantity);
 
        emit TokensMintedWithSignature(signer, receiver, _req);
    }
 
    /// @dev Returns whether a given address is authorized to sign mint requests.
    function _canSignMintRequest(address _signer)
        internal
        view
        virtual
        override
        returns (bool)
    {
        return _signer == owner();
    }
 
    /// @dev Collects and distributes the primary sale value of tokens being claimed.
    function _collectPriceOnClaim(
        address _primarySaleRecipient,
        uint256 _quantityToClaim,
        address _currency,
        uint256 _pricePerToken
    ) internal virtual {
        if (_pricePerToken == 0) {
            return;
        }
 
        uint256 totalPrice = (_quantityToClaim * _pricePerToken) / 1 ether;
        require(totalPrice > 0, "quantity too low");
 
        if (_currency == CurrencyTransferLib.NATIVE_TOKEN) {
            require(msg.value == totalPrice, "Must send total price.");
        }
 
        address saleRecipient = _primarySaleRecipient;
        CurrencyTransferLib.transferCurrency(
            _currency,
            msg.sender,
            saleRecipient,
            totalPrice
        );
    }
}

Base Contracts Implementing This Extension

Full API reference