Deploying a Contract

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

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Steps to Deploy a Contract

1. 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 provider.utxoManager.getUTXOs({
  address: wallet.p2tr,
});

UTXO Management

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

Learn more about UTXO Manager.

2. 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 bytecode = fs.readFileSync("your-contract.wasm");
// Or you can use the hex string directly:
// const bytecode = Buffer.from("your-contract-bytecode", "hex");

3. 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: wallet.keypair,
  network: networks.regtest,
  from: wallet.p2tr,
  utxos,
  bytecode,
  feeRate: 100,
  priorityFee: 10000n,
};

4. 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
);

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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.

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Full Example

import { networks } from "@btc-vision/bitcoin";
import {
  IDeploymentParameters,
  TransactionFactory,
  Wallet,
} from "@btc-vision/transaction";
import fs from "fs";
import { JSONRpcProvider } from "opnet";

// Initialize provider and wallet
const provider = new JSONRpcProvider(
  "https://regtest.opnet.org",
  networks.regtest
);
const wallet = Wallet.fromWif("your-private-key", networks.regtest);

// Fetch UTXOs for funding the deployment
const utxos = await provider.utxoManager.getUTXOs({
  address: wallet.p2tr,
});

// Contract bytecode (compiled contract code)
// You can get it from your wasm file, for example:
const bytecode = fs.readFileSync("your-contract.wasm");
// Or you can use the hex string directly:
// const bytecode = Buffer.from("your-contract-bytecode", "hex");

// Define deployment parameters
const deploymentParameters: IDeploymentParameters = {
  signer: wallet.keypair,
  network: networks.regtest,
  from: wallet.p2tr,
  utxos,
  bytecode,
  feeRate: 100,
  priorityFee: 10000n,
};

// Create and sign the deployment transaction
const transactionFactory = new TransactionFactory();
const deploymentResult = await transactionFactory.signDeployment(
  deploymentParameters
);

// Deployment result
console.log("Deployment Transaction:", deploymentResult.transaction);
console.log("Contract Address:", deploymentResult.contractAddress);
console.log("Tweaked Public Key:", deploymentResult.contractPubKey);
console.log("Taproot Address:", deploymentResult.p2trAddress);

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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.