Bako Safe SDK
Examples
Contract Interaction

Contract Interaction Example

Call smart contract methods from a multi-signature vault.

Overview

This example demonstrates how to:

  1. Connect to a vault using API token authentication
  2. Create a contract call transaction
  3. Sign and execute the transaction

Prerequisites

npm install bakosafe fuels

Complete Example

import { BakoProvider, Vault } from 'bakosafe';
import { Provider, bn, Contract, JsonAbi } from 'fuels';
 
// Your contract ABI
const CONTRACT_ABI: JsonAbi = {
  // ... your contract ABI
};
 
async function callContract() {
  // 1. Setup providers
  const networkUrl = 'https://mainnet.fuel.network/v1/graphql';
  const fuelProvider = new Provider(networkUrl);
 
  const provider = await BakoProvider.create(networkUrl, {
    apiToken: process.env.BAKO_API_TOKEN!
  });
 
  // 2. Load existing vault
  const vaultAddress = 'fuel1your-vault-address...';
  const vault = await Vault.fromAddress(vaultAddress, provider);
 
  console.log('Vault loaded:', vault.address.toB256());
 
  // 3. Create contract instance
  const contractId = '0xYourContractId...';
  const contract = new Contract(contractId, CONTRACT_ABI, fuelProvider);
 
  // 4. Build contract call
  const scope = contract.functions
    .your_method(param1, param2)
    .callParams({
      forward: {
        amount: bn(1000),
        assetId: provider.getBaseAssetId()
      }
    });
 
  // 5. Get transaction request from scope
  const request = await scope.getTransactionRequest();
 
  // 6. Create vault transaction with contract call
  const { tx, hashTxId } = await vault.transaction({
    name: 'Contract Call',
    witnesses: request.witnesses,
    assets: [] // Assets handled by forward in callParams
  });
 
  // 7. Add contract inputs/outputs to transaction
  tx.addContractInputAndOutput(contractId);
 
  console.log('Transaction created:', hashTxId);
 
  // 8. Sign the transaction
  await vault.sign(hashTxId);
  console.log('Transaction signed');
 
  // 9. Check if threshold met (for multi-sig)
  const details = await provider.service.getTransaction(hashTxId);
 
  if (details.status === 'pending_sender') {
    // All signatures collected, ready to send
    const result = await vault.send(hashTxId);
    console.log('Transaction sent:', result.id);
  } else {
    console.log('Waiting for more signatures...');
    console.log('Current status:', details.status);
  }
}
 
callContract().catch(console.error);

Step-by-Step Breakdown

1. Provider Setup

const fuelProvider = new Provider(networkUrl);
const provider = await BakoProvider.create(networkUrl, {
  apiToken: process.env.BAKO_API_TOKEN!
});

Two providers are needed:

  • fuelProvider: Native Fuel provider for contract interactions
  • BakoProvider: Bako provider for vault management

2. Load Vault

const vault = await Vault.fromAddress(vaultAddress, provider);

Recovers an existing vault by its address. The vault contains the multi-sig configuration.

3. Build Contract Call

const scope = contract.functions
  .your_method(param1, param2)
  .callParams({
    forward: {
      amount: bn(1000),
      assetId: provider.getBaseAssetId()
    }
  });

Build the contract call scope with:

  • Method name and parameters
  • Optional forwarded assets

4. Create Vault Transaction

const { tx, hashTxId } = await vault.transaction({
  name: 'Contract Call',
  witnesses: request.witnesses,
  assets: []
});

Creates a Bako transaction that wraps the contract call.

5. Sign and Send

await vault.sign(hashTxId);
await vault.send(hashTxId);

Sign with current signer and send when threshold is met.

With Multiple Signers

// Signer 1 creates and signs
const { tx, hashTxId } = await vault.transaction(params);
await vault.sign(hashTxId);
 
// Share hashTxId with other signers...
 
// Signer 2 signs
const vault2 = await Vault.fromAddress(vaultAddress, provider2);
await vault2.sign(hashTxId);
 
// After all signatures collected
const result = await vault.send(hashTxId);

Error Handling

try {
  const { tx, hashTxId } = await vault.transaction(params);
  await vault.sign(hashTxId);
  await vault.send(hashTxId);
} catch (error) {
  if (error.message.includes('contract')) {
    console.error('Contract execution failed');
  } else if (error.message.includes('gas')) {
    console.error('Insufficient gas');
  } else {
    console.error('Transaction failed:', error);
  }
}

Next Steps

OverviewToken Transfer