damonpickett/nft-tutorial

NFT Minter

Tutorial from Open Sea Docs

Summary

This app gives me the ability to mint a digital file via my CLI. The NFT.sol file communicates with the rinkeby testnet blockchain while the various /scripts javascript files allow me to use my smart contract via my CLI.

Tech Stack

• Javascript
• Solidity: For writing smart contract.
• ethers.js Library for interacting with the Ethereum Blockchain. Used in helpers.js to get provider and user wallet.
• Hardhat: Through hardhat I'm able to use terminal commands (eg. npx hardhat compile, npx hardhat deploy, npx hardhat mint, etc.) to interact with the testnet. My javascript files deploy.js and mint.js import hardhat to achieve this. E.G.:

const { task } = require("hardhat/config");

task("mint", "Mints from the NFT contract")
.addParam("address", "The address to receive a token")
.setAction(async function (taskArguments, hre) {
    const contract = await getContract("NFT", hre);
    const transactionResponse = await contract.mintTo(taskArguments.address, {
        gasLimit: 500_000,
    });
    console.log(`Transaction Hash: ${transactionResponse.hash}`);
});

The code above allows for the terminal command npx hardhat mint {address}

• Alchemy: My Alchemy project API key is used in my hardhat configuration file.
• nft.storage: This app allows me to upload files (images, metadata) to IPFS and returns a CID which I then use to set the base URI in my smart contract.

1. Setting up a basic project

• Created files scripts and contracts
• Wrote first iteration of NFT.sol
• Created .env file for ALCHEMY_KEY and ACCOUNT_PRIVATE_KEY (MM)
• Wrote first iteration of hardhat.config.js
• First compile with npx hardhat compile
• Wrote first iteration of deploy.js
• Deployed contract

2. Minting from your new contract and improvements

• Refactored deploy.js to use hardhat for CLI commands and to import getAccount() from helpers.js
• Created helpers.js file for commonly used functions
• Created mint.js file to allow us to call mintTo() function from our NFT contract in our CLI
• Minted a token to wallet through CLI npx hardhat mint --address {wallet address}

3. Adding metadata and payments to your contract

• Convert metadata and images folders to .car files via CLI: npx ipfs-car --pack metadata --output metadata.car
• Upload car files to ipfs via nft.storage
• nft.storage provides you with a CID which is used to set your base uri (eg. "https://{CID}.ipfs.dweb.link/metadata/")
• Compile, deploy contract in CLI. Take new contract address and update .env file. Source .env file in CLI: source .env
• Then you set the base token URI, then you mint. All via CLI: npx hardhat set-base-token-uri --base-url https://{CID}.ipfs.dweb.link/metadata/ npx hardhat mint --address {your wallet address} x 3 or however many files are in your metadata folder.
• The metadata, which is saved in IPFS, is what is minted. The metadata contains the link to the image which is also saved on IPFS. 'Minted' simply means that an ERC token, which points to the metadata saved on IPFS, has been assigned to my wallet and this transaction has been recorded on the blockchain.

4. Smart contract improvements

Verifying smart contract on Etherscan

In part 4 of the tutorial we begin learning how to verify your smart contract on Etherscan. This allows us to read and interact with the contract on Etherscan. It's also supposed to help build trust with the community since it allows them to ensure the code written is safe. So I created an Etherscan account and generated an api key and added ETHERSCAN_API_KEY to my .env file. I then entered npx hardhat verify {contract address} in the terminal. This produced an error initially but the contract was verified and I was able to see my contract on Etherscan.

Setting a token supply limit

A constant is added to the top of the contract: uint256 public constant TOTAL_SUPPLY = 10_000;

The following lines of code were added to the mintTo() function in NFT.sol:

uint256 tokenId = currentTokenId.current();
require(tokenId < TOTAL_SUPPLY, "Max supply reached");

If the require line resolves to false then the function will not execute and the the user will not be charged.

Setting a price for minting your NFT

A constant is added to the top of the contract:

uint256 public constant MINT_PRICE = 0.08 ether;

The payable modifier is added to the mintTo() function. And this require line is added to the function:

require(msg.value == MINT_PRICE, "Transaction value did not equal the mint price");

Withdrawing Funds

After adding import "@openzeppelin/contracts/security/PullPayment.sol"; and extending contract with PullPayment (contract NFT is ERC721, PullPayment), and after re-deploying my contract and verifying, I can now navigate to my contract on Etherscan and withdraw payments to an address of my choosing (Contract -> Write Contract)

Roles and Access

To prevent anyone other than myself from withdrawing funds from my contract, I've added import "@openzeppelin/contracts/access/Ownable.sol"; to my imports, extended contract with Ownable and added this function:

function withdrawPayments(address payable payee) public override onlyOwner virtual {
   super.withdrawPayments(payee);
}

The ownership contract also gives me access to helpers such as renounceOwnership(), transferOwnership(), and isOwner().

---

May 23rd, 2022, 1:12pm PST

At present, the primary functions of this app are:

• npx hardhat check-balance: Returns the account balance of the given wallet/network.
• npx hardhat deploy: Deploys the NFT.sol contract. Returns the address that the contract has been deployed to.
• npx hardhat mint --address {wallet address}: Mints a token to the given wallet address. Returns the transaction hash.

These functions are executed through the terminal.

May 24th, 2022

Converted images folder and metadata folder to .car files via terminal and uploaded to IPFS via nft.storage

Added NFT contract functions to mint.js script

Ran terminal commands to mint tokens to my 'NFT Wallet' wallet:

• npx hardhat compile
• npx hardhat deploy
• npx hardhat set-base-token-uri --base-url "https://{CID}.ipfs.dweb.link/metadata/"
• npx hardhat mint --address {wallet address} x 3
• npx hardhat token-uri --token-id {token id number} (returns corresponding metadata)

---

Next Steps

• Learn how to deploy an app with a front-end that charges for minting service.
• Build my own NFT project