_nft

_nftId

_startingBid

sender

amount

winner

Start

bidder

Withdraw

bids

endAt

ended

highestBid

highestBidder

nftId

seller

start

started

withdraw

Auction

    1) Seller of NFT deploys this contract.
    2) Auction lasts for 7 days.
    3) Participants can bid by depositing ETH greater than the current highest bidder.
    4) All bidders can withdraw their bid if it is not the current highest bid.

After the auction

    1) Highest bidder becomes the new owner of NFT.
    2) The seller receives the highest bid of ETH.


Adds a bid greater than the current highest bid.

A list of the current bids for an address.

The timestamp at which the auction begins.

Withdraws bids for an account if that address is not the current highest bidder.

English Auction

An English auction is a process of selling goods and the most common form of auction. The price starts low and increases as buyers bid for the item until one buyer is left willing to pay a certain amount and a higher bid isn't received during the given time period.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

interface IERC721 {
    function safeTransferFrom(address from, address to, uint tokenId) external;

    function transferFrom(address, address, uint) external;
}

contract EnglishAuction {
    event Start();
    event Bid(address indexed sender, uint amount);
    event Withdraw(address indexed bidder, uint amount);
    event End(address winner, uint amount);

    IERC721 public nft;
    uint public nftId;

    address payable public seller;
    uint public endAt;
    bool public started;
    bool public ended;

    address public highestBidder;
    uint public highestBid;
    mapping(address => uint) public bids;

    constructor(address _nft, uint _nftId, uint _startingBid) {
        nft = IERC721(_nft);
        nftId = _nftId;

        seller = payable(msg.sender);
        highestBid = _startingBid;
    }

    function start() external {
        require(!started, "started");
        require(msg.sender == seller, "not seller");

        nft.transferFrom(msg.sender, address(this), nftId);
        started = true;
        endAt = block.timestamp + 7 days;

        emit Start();
    }

    function bid() external payable {
        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(msg.sender, msg.value);
    }

    function withdraw() external {
        uint bal = bids[msg.sender];
        bids[msg.sender] = 0;
        payable(msg.sender).transfer(bal);

        emit Withdraw(msg.sender, bal);
    }

    function end() external {
        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(highestBidder, highestBid);
    }
}


English Auction

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ABI

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English Auction

*Visit desktop site to download or deploy

Version

Creator

Recent Use

Last Publish

Get Cookin'Share

ABI

Bytecode

Verification

Recent Use

Last Publish

Solidity Compiler

Version

Creator

Get Cookin'
Share