BLS Snap ·

The MetaMask Snap for BLS Wallet

bls-snap-demo.mov

Terminology

1. Action - Smart contract calldata (includes target contract, data and value).
2. Operation - Ordered list of actions.
3. Bundle - Ordered list of operations.
4. Aggreegator - Service which accepts BLS signed transactions and bundles them into one for submission.

Prerequisites

1. Chrome browser

2. MetaMask Flask

   Install MetaMask Flask in your Chrome browser. If you have MetaMask installed, you need to disable it because MetaMask does not support Snaps and cannot work with MetaMask Flask at the same time. Take a look FAQ

3. Node.js v16+

4. Yarn

Getting Started

1. Clone the repository

   mkdir ./bls-snap
   cd ./bls-snap
   git clone https://github.com/aquiladev/bls-snap.git .
   

2. Install dependencies

   yarn install
   

3. Run snap with UI

   yarn start
   

   Note: If you have issues on the snap installation, take a look Troubleshooting block.
4. Run tests

   yarn test
   

Snap APIs

The snap has APIs which allow dapps communicate with it.

A dapp must request MetaMask, in order to invoke snap API

await ethereum.request({
  method: 'wallet_invokeSnap',
  params: {
    snapId,
    request: {
      method: {SNAP_API},
      params: {SNAP_API_PARAMS},
    },
  },
})

List of APIs

• ping - Test API, dapp can hit the API and receive pong in response.
• bls_getNetworks - Returns list of supported networks with their configurations.
• bls_recoverAccounts - Returns list of accounts from snap state.
• bls_createAccount - Creates and returns new account. Snap uses seedprase from MetaMask through its API snap_getBip44Entropy in order to generate accounts. It allows to re-create the same accounts after snap re-installation.
• bls_addErc20Token - Adds ERC20 token to snap state.
• bls_getErc20Tokens - Returns list of ERC20 tokens from snap state.
• bls_removeErc20Token - Removes ERC20 token from snap state.
• bls_getErc20TokenBalance - Returns ERC20 token balance from snap state.
• bls_getActions - Returns list of actions from snap state.
• bls_addAction - Adds new action to snap state.
• bls_removeAction - Removes action from snap state.
• bls_getBundles - Returns list of bundles from snap state.
• bls_getBundle - Returns the bundle from snap state with status check.
• bls_sendBundle - Signs and sends new bundle with ordered list of operations to an aggreegator.

API params

API	Required	Optional
ping
bls_getNetworks
bls_recoverAccounts	chainId
bls_createAccount	chainId	addressIndex
bls_addErc20Token	chainId, tokenAddress, tokenName, tokenSymbol	tokenDecimals (default: 18)
bls_getErc20Tokens	chainId
bls_removeErc20Token	chainId, tokenAddress
bls_getErc20TokenBalance	chainId, tokenAddress, userAddress
bls_getActions	chainId, senderAddress
bls_addAction	chainId, senderAddress, contractAddress, encodedFunction	value (default: 0), functionFragment
bls_removeAction	chainId, id
bls_getBundles	chainId, senderAddress
bls_getBundle	chainId, bundleHash
bls_sendBundle	chainId, senderAddress, actionIds

Troubleshooting

1. mcl-wasm has strange behaviour during execution in snap sandbox. one line changed in file mcl_c.js:

   if (scriptDirectory.indexOf("blob:") !== 0) {
   

   to

   if (typeof scriptDirectory === 'string' && scriptDirectory.indexOf("blob:") !== 0) {
   

   Note: This fix requires snap re-installation. You need to build the snap, remove it from MetaMask and install it again.