bls-wallet-clients

BLS Wallet Clients

Client libraries for interacting with BLS Wallet components

Network Config

Deployed contract addresses and metadata.

import { NetworkConfig, getConfig } from 'bls-wallet-clients';

const netCfg: NetworkConfig = await getConfig(
  '/path/to/network/config',
  async (path) => ... /* fetch, fs.readFile, etc. */
);
// Read from netCfg.addresses.verificationGateway, etc.

Aggregator

Exposes typed functions for interacting with the Aggregator's HTTP API.

Add a bundle to an aggregator

import { Aggregator } from "bls-wallet-clients";

const aggregator = new Aggregator("https://arbitrum-goerli.blswallet.org");
const resp = await aggregator.add(bundle); // See BlsWalletWrapper section below
// Aggregator did not accept bundle
if ("failures" in resp) {
  throw new Error(resp.failures.join(", "));
}

Get the bundle receipt that contains the transaction hash you can lookup on a block explorer

You will have to poll for the bundle receipt once you have added a bundle to an aggregator. The transaction hash is located on the bundle receipt. The property you need is bundleReceipt.transactionHash. This represents the transaction hash for the bundle submitted to the Verification Gatewaty, and can be used in a block explorer.

Note this transaction is reprentative of the entire bundle submitted by the aggregator, and does not represent individual operations. To retrieve information about individual operations, use the get getOperationResults helper method which is explained under the VerificationGateway section below.

import { Aggregator } from "bls-wallet-clients";

const aggregator = new Aggregator("https://arbitrum-goerli.blswallet.org");
const resp = await aggregator.add(bundle); // See BlsWalletWrapper section below
// Aggregator did not accept bundle
if ("failures" in resp) {
  throw new Error(resp.failures.join(", "));
}

let receipt;
while (!receipt) {
  receipt = await aggregator.lookupReceipt(resp.hash);
  // There was an issue submitting the bundle on chain
  if (receipt && "submitError" in receipt) {
    throw new Error(receipt.submitError);
  }
  // Some function which waits i.e. setTimeout
  await sleep(5000);
}

BlsWalletWrapper

Wraps a BLS wallet, storing the private key and providing .sign(...) to produce a Bundle, that can be used with aggregator.add(...). Make sure the bls wallet you're trying to use has enough ETH to send transactions. You can either fund a wallet before it's created, or after the wallet is lazily created from its first transaction (bundle).

import { BlsWalletWrapper } from "bls-wallet-clients";

const wallet = await BlsWalletWrapper.connect(
  privateKey,
  verificationGatewayAddress,
  provider,
);

const bundle = wallet.sign({
  nonce: await wallet.Nonce(),
  actions: [
    {
      ethValue: 0,
      contractAddress: someToken.address, // An ethers.Contract
      encodedFunction: someToken.interface.encodeFunctionData("transfer", [
        "0x...some address...",
        ethers.BigNumber.from(1).pow(18),
      ]),
    },
    // Additional actions can go here. When using multiple actions, they'll
    // either all succeed or all fail.
  ],
});

await aggregator.add(bundle);

Sending a regular ETH transaction

// Follow the same steps as the first BlsWalletWrapper example, but construct the bundle actions like so:
const amountToTransfer = ethers.utils.parseUnits("1");
const reciever = "0x1234...";

const bundle = wallet.sign({
  nonce,
  actions: [
    {
      ethValue: amountToTransfer, // amount of ETH you want to transfer
      contractAddress: reciever, // receiver address. Can be a contract address or an EOA
      encodedFunction: "0x", // leave this as "0x" when just sending ETH
    },
  ],
});

Constructing actions to be agnostic to both ETH transfers and contract interactions

// Follow the same steps as the first BlsWalletWrapper example, but construct the bundle actions like so:
const transactions = [
  {
    value: ethers.utils.parseUnits("1"), // amount of ETH you want to transfer
    to: "0x1234...", // to address. Can be a contract address or an EOA
  },
];

const actions: ActionData[] = transactions.map((tx) => ({
  ethValue: tx.value ?? "0",
  contractAddress: tx.to,
  encodedFunction: tx.data ?? "0x", // in this example, there is no data property on the tx object, so "0x" will be used
}));

const bundle = wallet.sign({
  nonce,
  actions,
});

Estimating and paying fees

User bundles must pay fees to compensate the aggregator. Fees can be paid by adding an additional action to the users bundle that pays tx.origin. For more info on how fees work, see aggregator fees.

Practically, this means you have to first estimate the fee using aggregator.estimateFee, and then add an additional action to a user bundle that pays the aggregator with the amount returned from estimateFee. When estimating a payment, you should include this additional action with a payment of zero wei, otherwise the additional action will increase the fee that needs to be paid. Additionally, the feeRequired value returned from estimateFee is the absolute minimum fee required at the time of estimation, therefore, you should pay slightly extra to ensure the bundle has a good chance of being submitted successfully.

Paying aggregator fees with native currency (ETH)

import { BlsWalletWrapper, Aggregator } from "bls-wallet-clients";

const wallet = await BlsWalletWrapper.connect(
  privateKey,
  verificationGatewayAddress,
  provider,
);
const aggregator = new Aggregator("https://arbitrum-goerli.blswallet.org");

// Create a fee estimate bundle
const estimateFeeBundle = wallet.sign({
  nonce,
  actions: [
    ...actions, // ... add your user actions here (approve, transfer, etc.)
    {
      ethValue: 1,
      // Provide 1 wei with this action so that the fee transfer to
      // tx.origin can be included in the gas estimate.
      contractAddress: aggregatorUtilitiesContract.address,
      encodedFunction:
        aggregatorUtilitiesContract.interface.encodeFunctionData(
          "sendEthToTxOrigin",
        ),
    },
  ],
});

const feeEstimate = await aggregator.estimateFee(estimateFeeBundle);

// Add a safety premium to the fee to account for fluctuations in gas estimation
const safetyDivisor = 5;
const feeRequired = BigNumber.from(feeEstimate.feeRequired);
const safetyPremium = feeRequired.div(safetyDivisor);
const safeFee = feeRequired.add(safetyPremium);

const bundle = wallet.sign({
  nonce: await wallet.Nonce(),
  actions: [
    ...actions, // ... add your user actions here (approve, transfer, etc.)
    {
      ethValue: safeFee, // fee amount
      contractAddress: aggregatorUtilitiesContract.address,
      encodedFunction:
        aggregatorUtilitiesContract.interface.encodeFunctionData(
          "sendEthToTxOrigin",
        ),
    },
  ],
});

Paying aggregator fees with custom currency (ERC20)

The aggregator must be set up to accept ERC20 tokens in order for this to work.

import { BlsWalletWrapper, Aggregator } from "bls-wallet-clients";

const wallet = await BlsWalletWrapper.connect(
  privateKey,
  verificationGatewayAddress,
  provider,
);
const aggregator = new Aggregator("https://arbitrum-goerli.blswallet.org");

// Create a fee estimate bundle
const estimateFeeBundle = wallet.sign({
  nonce,
  actions: [
    ...actions, // ... add your user actions here (approve, transfer, etc.)
    {
      ethValue: 0,
      contractAddress: tokenContract.address,
      encodedFunction: tokenContract.interface.encodeFunctionData("approve", [
        aggregatorUtilitiesContract.address,
        1,
      ]),
    },
    {
      ethValue: 0,
      contractAddress: aggregatorUtilitiesContract.address,
      encodedFunction: aggregatorUtilitiesContract.interface.encodeFunctionData(
        "sendTokenToTxOrigin",
        [tokenContract.address, 1],
      ),
    },
  ],
});

const feeEstimate = await aggregator.estimateFee(estimateFeeBundle);

// Add a safety premium to the fee to account for fluctuations in gas estimation
const safetyDivisor = 5;
const feeRequired = BigNumber.from(feeEstimate.feeRequired);
const safetyPremium = feeRequired.div(safetyDivisor);
const safeFee = feeRequired.add(safetyPremium);

const bundle = wallet.sign({
  nonce: await wallet.Nonce(),
  actions: [
    ...actions, // ... add your user actions here (approve, transfer, etc.)

    // Note the additional approve action when transfering ERC20 tokens
    {
      ethValue: 0,
      contractAddress: tokenContract.address,
      encodedFunction: tokenContract.interface.encodeFunctionData("approve", [
        aggregatorUtilitiesContract.address,
        safeFee, // fee amount
      ]),
    },
    {
      ethValue: 0,
      contractAddress: aggregatorUtilitiesContract.address,
      encodedFunction: aggregatorUtilitiesContract.interface.encodeFunctionData(
        "sendTokenToTxOrigin",
        [
          tokenContract.address,
          safeFee, // fee amount
        ],
      ),
    },
  ],
});

VerificationGateway

Exposes VerificationGateway and VerificationGateway__factory generated by typechain to enable typed interactions with the VerificationGateway.

import { VerificationGateway__factory } from "bls-wallet-clients";

const verificationGateway = VerificationGateway__factory.connect(
  verificationGatewayAddress,
  signer, // An ethers signer
);

await verificationGateway.processBundle(bundle);

You can get the results of the operations in a bundle using getOperationResults.

import { getOperationResults, decodeError } from 'bls-wallet-clients';

...

const txn = await verificationGateway.processBundle(bundle);
const txnReceipt = txn.wait();
const opResults = getOperationResults(txnReceipt);

// Includes data from WalletOperationProcessed event,
// as well as parsed errors with action index
const { error } = opResults[0];
console.log(error?.actionIndex); // ex. 0 (as BigNumber)
console.log(error?.message); // ex. "some require failure message"

// If you want more granular ability to decode an error message
// you can use the decodeError function.
const errorData = '0x5c66760100000000.............000000000000';
const opResultError = decodeError(errorData);
console.log(opResultError.actionIndex); // ex. 0 (as BigNumber)
console.log(opResultError.message); // ex. "ERC20: insufficient allowance"

Signer

Utilities for signing, aggregating and verifying transaction bundles using the bls signature scheme. Bundles are actioned in contracts.

Useful in the aggregator for verification and aggregation, and in the extension for signing and aggregation.

import ethers from "ethers";
import { initBlsWalletSigner } from "bls-wallet-clients";

(async () => {
  const privateKey = "0x...256 bits of private hex data here";

  const signer = await initBlsWalletSigner({ chainId: 10, privateKey });

  const someToken = new ethers.Contract(
    ...
    // See https://docs.ethers.io/v5/getting-started/
  );

  const bundle = signer.sign(
    {
      nonce: ethers.BigNumber.from(0),
      ethValue: ethers.BigNumber.from(0),
      contractAddress: someToken.address,

      // If you don't want to call a function and just send `ethValue` above,
      // use '0x' to signify an empty byte array here
      encodedFunction: someToken.interface.encodeFunctionData("transfer", [
        "0x...some address...",
        ethers.BigNumber.from(10).pow(18),
      ]),
    },
  );

  // Send bundle to an aggregator or use it with VerificationGateway directly.
})();

Local Development

Setup

yarn install

Build

yarn build

Tests

yarn test

Use in Extension or another project

yarn build
yarn link
cd other/project/dir
yarn "link bls-wallet-clients"

Troubleshooting tips

• Make sure your bls-wallet-clients package is up-to-date and check out our releases page for info on breaking changes.
• Check network values such as the verification gateway address or the aggregator url are up-to-date. The most up-to-date values are located in the relevant network config file. If you're deploying to a custom network, you'll have to check these against your own records as these won't be in the network directory.