IDENFTs is a NFT Marketplace start-up that allows users to upload the NFT to IPFS, and allow them to make API requests to fetch all the IPFS blockchain smart contract data.
- Solidity
- Next.js
- React
- OpenZeppelin
- Hardhat
- IPFS
The smart contract for the NFT marketplace is written in Solidity and uses OpenZeppelin libraries for ERC721 tokens and Counters. The contract is named Idenfts and it includes a mapping of token IDs to MarketItem structs, which represent items in the marketplace.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "hardhat/console.sol";
contract Idenfts is ERC721URIStorage {
using Counters for Counters.Counter;
Counters.Counter private _tokenIds;
Counters.Counter private _itemsSold;
uint256 listingPrice = 0.025 ether;
address payable owner;
mapping(uint256 => MarketItem) private idToMarketItem;
struct MarketItem {
uint256 tokenId;
address payable seller;
address payable owner;
uint256 price;
bool sold;
}
event MarketItemCreated(
uint256 indexed tokenId,
address seller,
address owner,
uint256 price,
bool sold
);
modifier onlyOwner() {
require(
msg.sender == owner,
"only owner of the marketplace can change the listing price"
);
_;
}
constructor() ERC721("Metaverse Tokens", "METT") {
owner = payable(msg.sender);
}
/* Updates the listing price of the contract */
function updateListingPrice(uint256 _listingPrice)
public
payable
onlyOwner
{
require(
owner == msg.sender,
"Only marketplace owner can update listing price."
);
listingPrice = _listingPrice;
}
/* Returns the listing price of the contract */
function getListingPrice() public view returns (uint256) {
return listingPrice;
}
/* Mints a token and lists it in the marketplace */
function createToken(string memory tokenURI, uint256 price)
public
payable
returns (uint256)
{
_tokenIds.increment();
uint256 newTokenId = _tokenIds.current();
_mint(msg.sender, newTokenId);
_setTokenURI(newTokenId, tokenURI);
createMarketItem(newTokenId, price);
return newTokenId;
}
function createMarketItem(uint256 tokenId, uint256 price) private {
require(price > 0, "Price must be at least 1 wei");
require(
msg.value == listingPrice,
"Price must be equal to listing price"
);
idToMarketItem[tokenId] = MarketItem(
tokenId,
payable(msg.sender),
payable(address(this)),
price,
false
);
_transfer(msg.sender, address(this), tokenId);
emit MarketItemCreated(
tokenId,
msg.sender,
address(this),
price,
false
);
}
/* allows someone to resell a token they have purchased */
function resellToken(uint256 tokenId, uint256 price) public payable {
require(
idToMarketItem[tokenId].owner == msg.sender,
"Only item owner can perform this operation"
);
require(
msg.value == listingPrice,
"Price must be equal to listing price"
);
idToMarketItem[tokenId].sold = false;
idToMarketItem[tokenId].price = price;
idToMarketItem[tokenId].seller = payable(msg.sender);
idToMarketItem[tokenId].owner = payable(address(this));
_itemsSold.decrement();
_transfer(msg.sender, address(this), tokenId);
}
/* Creates the sale of a marketplace item */
/* Transfers ownership of the item, as well as funds between parties */
function createMarketSale(uint256 tokenId) public payable {
uint256 price = idToMarketItem[tokenId].price;
require(
msg.value == price,
"Please submit the asking price in order to complete the purchase"
);
idToMarketItem[tokenId].owner = payable(msg.sender);
idToMarketItem[tokenId].sold = true;
_itemsSold.increment();
_transfer(address(this), msg.sender, tokenId);
payable(owner).transfer(listingPrice);
payable(idToMarketItem[tokenId].seller).transfer(msg.value);
idToMarketItem[tokenId].seller = payable(address(0));
}
/* Returns all unsold market items */
function fetchMarketItems() public view returns (MarketItem[] memory) {
uint256 itemCount = _tokenIds.current();
uint256 unsoldItemCount = _tokenIds.current() - _itemsSold.current();
uint256 currentIndex = 0;
MarketItem[] memory items = new MarketItem[](unsoldItemCount);
for (uint256 i = 0; i < itemCount; i++) {
if (idToMarketItem[i + 1].owner == address(this)) {
uint256 currentId = i + 1;
MarketItem storage currentItem = idToMarketItem[currentId];
items[currentIndex] = currentItem;
currentIndex += 1;
}
}
return items;
}
/* Returns only items that a user has purchased */
function fetchMyNFTs() public view returns (MarketItem[] memory) {
uint256 totalItemCount = _tokenIds.current();
uint256 itemCount = 0;
uint256 currentIndex = 0;
for (uint256 i = 0; i < totalItemCount; i++) {
if (idToMarketItem[i + 1].owner == msg.sender) {
itemCount += 1;
}
}
MarketItem[] memory items = new MarketItem[](itemCount);
for (uint256 i = 0; i < totalItemCount; i++) {
if (idToMarketItem[i + 1].owner == msg.sender) {
uint256 currentId = i + 1;
MarketItem storage currentItem = idToMarketItem[currentId];
items[currentIndex] = currentItem;
currentIndex += 1;
}
}
return items;
}
/* Returns only items a user has listed */
function fetchItemsListed() public view returns (MarketItem[] memory) {
uint256 totalItemCount = _tokenIds.current();
uint256 itemCount = 0;
uint256 currentIndex = 0;
for (uint256 i = 0; i < totalItemCount; i++) {
if (idToMarketItem[i + 1].seller == msg.sender) {
itemCount += 1;
}
}
MarketItem[] memory items = new MarketItem[](itemCount);
for (uint256 i = 0; i < totalItemCount; i++) {
if (idToMarketItem[i + 1].seller == msg.sender) {
uint256 currentId = i + 1;
MarketItem storage currentItem = idToMarketItem[currentId];
items[currentIndex] = currentItem;
currentIndex += 1;
}
}
return items;
}
}The smart contract is deployed using Hardhat. The deployment script is located in scripts/deploy.js.
To run the project, use the following commands:
- npm run dev: Runs the app in development mode.
- npm run build: Builds the app for production.
- npm run start: Starts the built app in production mode.
Contributions are welcome. Please make sure to update tests as appropriate.