Source

AUCTION

Simple Nft Auction

• auction type: English auction
• nft type : ERC721 (1 of 1)

how to:

• deploy by using
• • nft erc721 address (you are owner)
• • nft id (you are owner)
• • set the price for starting BID price

test:

• for testing this, you will need erc721 contract like -> here
• remember to call approve for all for using in auction
• for better experiance, in line 74 change value

features:

• add ERC1155
• change nft address function
• custom ERC20 for pay (buy nft)
• seller can not be bidder (require on bid function)

important:

withdraw by using address balance is easiest for hacking, please ensure for using by this term & role

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Review

• Start

function _startAuction() internal returns (bool) {
    require(!started, "started");
    require(msg.sender == seller, "not seller"); // walletOfOwner(address) => seller
    nft.transferFrom(msg.sender, address(this), nftId);
    started = true;
    endAt = block.timestamp + 2 days; // 7 days is a very famous type for artists :)
    _idCounter.increment();
    emit Start(_idCounter.current());
    return true;
}

• Bid

function _bid() internal returns (bool) {
    require(started, "not started");
    require(block.timestamp < endAt, "ended");
    require(msg.value > highestBid, "value < highest");
    if (highestBidder != address(0)) {
        bids[highestBidder] += highestBid;
    }
    highestBidder = msg.sender;
    highestBid = msg.value;
    emit Bid(_idCounter.current(), msg.sender, msg.value);
    return true;
}

• End

function _end() internal returns (bool) {
    require(started, "not started");
    require(block.timestamp >= endAt, "not ended");
    require(!ended, "ended");
    ended = true;
    if (highestBidder != address(0)) {
        nft.safeTransferFrom(address(this), highestBidder, nftId);
        seller.transfer(highestBid);
    } else {
        nft.safeTransferFrom(address(this), seller, nftId);
    }
    emit End(_idCounter.current(), highestBidder, highestBid);
    return true;
}