Deploying a Contract

Deploying a smart contract on OP_NET using WalletConnect requires careful handling of UTXOs and constructing deployment parameters. This guide explains the process of using TransactionFactory to sign and deploy contracts.

---

Steps to Deploy a Contract

1. Get Required Parameters

Before deploying a contract, ensure you have the following parameters:

• account: Wallet account for transaction signing.

import { useWallet } from "@btc-vision/walletconnect";

const { account } = useWallet();

2. Obtaining Proper UTXOs

Before building a transaction, you need to gather the required UTXOs for funding. Use the utxoManager from the JSONRpcProvider to fetch UTXOs associated with your address.

const utxos = await account.provider.utxoManager.getUTXOs({
  address: account.address.p2tr(account.network),
});

UTXO Management

Ensure you have enough UTXOs to cover the transaction inputs, gas fees, and any additional outputs.

Learn more about UTXO Manager.

3. Fetching Contract Bytecode

Retrieve the contract bytecode (compiled contract code) to be deployed. You can read the bytecode from a compiled .wasm file or use the hex string directly.

const bytecodeArrayBuffer = await fetch("contract.wasm").then((res) =>
  res.arrayBuffer()
);
const bytecode = Buffer.from(new Uint8Array(bytecodeArrayBuffer));
// OR directly define the bytecode as a hex string
// const bytecodeBuffer = Buffer.from("your-contract-bytecode", "hex");

4. Constructing Deployment Parameters

The IDeploymentParameters interface defines the required parameters for contract deployment. Ensure you provide the signer, network, contract bytecode, and other necessary details.

const deploymentParameters: IDeploymentParameters = {
  signer: account.signer!, // OP_WALLET does not require a signer
  network: account.network,
  from: account.address.p2tr(account.network),
  bytecode: bytecode,
  utxos: utxos,
  feeRate: 100,
  priorityFee: 10_000n,
  gasSatFee: 10_000n,
};

5. Signing the Deployment Transaction

Use the signDeployment method from TransactionFactory to sign the deployment transaction. This method returns a DeploymentResult object containing the signed transaction and contract details.

const transactionFactory = new TransactionFactory();
const deploymentResult = await transactionFactory.signDeployment(
  deploymentParameters
);

console.log(deploymentResult); // This is not sent to the blockchain yet

6. Broadcasting the Transaction

After signing the deployment transaction, you can broadcast it to the network using the sendRawTransactions method. This step finalizes the contract deployment process.

const transactionReceipt = await account.provider.sendRawTransactions(
  deploymentResult.transaction
);

const txId = transactionReceipt[1].result;
const contractAddress = deploymentResult.contractAddress;

console.log(`Transaction ID: ${txId}`);
console.log(`Contract Address: ${contractAddress}`);

---

Object Definitions

DeploymentResult Object

Property	Type	Description
transaction	string	Array of raw transaction strings.
contractAddress	string	Contract's Taproot address.
contractPubKey	string	Contract's tweaked public key.
p2trAddress	string	Contract's P2TR address.
utxos	UTXO[]	Array of new UTXOs after deployment.

---

Full Example

import {
  IDeploymentParameters,
  TransactionFactory,
} from "@btc-vision/transaction";
import { SupportedWallets, useWallet } from "@btc-vision/walletconnect";

function DeployContract() {
  const { account, connect, disconnect } = useWallet();

  async function deployContract() {
    if (!account) throw new Error("Connect wallet first");

    const utxos = await account.provider.utxoManager.getUTXOs({
      address: account.address.p2tr(account.network),
    });

    const bytecodeArrayBuffer = await fetch("contract.wasm").then((res) =>
      res.arrayBuffer()
    );
    const bytecode = Buffer.from(new Uint8Array(bytecodeArrayBuffer));

    const deploymentParameters: IDeploymentParameters = {
      signer: account.signer!, // OP_WALLET does not require a signer
      network: account.network,
      from: account.address.p2tr(account.network),
      bytecode: bytecode,
      utxos: utxos,
      feeRate: 100,
      priorityFee: 10_000n,
      gasSatFee: 10_000n,
    };

    const transactionFactory = new TransactionFactory();
    const deploymentResult = await transactionFactory.signDeployment(
      deploymentParameters
    );

    console.log(deploymentResult); // This is not sent to the blockchain yet

    const transactionReceipt = await account.provider.sendRawTransactions(
      deploymentResult.transaction
    );

    const txId = transactionReceipt[1].result;
    const contractAddress = deploymentResult.contractAddress;

    console.log(`Transaction ID: ${txId}`);
    console.log(`Contract Address: ${contractAddress}`);
  }

  return (
    <div>
      {account ? (
        <div>
          <p>Connected Address: {account.address.p2tr(account.network)}</p>
          <button onClick={deployContract}>Deploy Contract</button>
          <button onClick={disconnect}>Disconnect</button>
        </div>
      ) : (
        <button onClick={() => connect(SupportedWallets.OP_WALLET)}>
          Connect Wallet
        </button>
      )}
    </div>
  );
}

export default DeployContract;

---

Best Practices

• Ensure your wallet has sufficient UTXOs to fund the deployment and associated fees.
• Adjust the feeRate and priorityFee parameters based on current network conditions to minimize costs.
• Before deploying on mainnet, test your contract deployment process on regtest or testnet to avoid unnecessary costs.