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Account Abstraction for iOS

Particle Network’s AA SDK, existing at the center of its Smart Wallet-as-a-Service, facilitates flexible end-to-end utilization of ERC-4337 account abstraction, natively supporting modular smart account implementations, Paymasters, and natural Bundler usage. Within iOS applications, the Particle Network AA SDK can be used (in tandem with Particle Auth or Particle Connect) to refine user experience through account abstraction.

Details on configuration, initialization, and utilization are listed below.

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Getting Started

To get started, you’ll need to have already integrated either Particle Connect or Particle Auth within your iOS application. If you haven’t, head over to those pages, follow the configuration process, and return here. Otherwise, you can begin by including ParticleAA within your Podfile, as shown below:

Podfile
pod 'ParticleAA'

This new addition to your Podfile can then be settled and installed by running the command below:

Terminal
pod install --repo-update

Important details before initialization

Before initializing the SDK, there are a few points to keep in mind, specifically regarding the utilization of Paymasters (to sponsor gas fees, pay for gas in ERC-20 tokens, etc.)

- All Testnets automatically have the Verifying Particle Network Omnichain Verifying Paymaster enabled. Transactions requesting it will automatically be sponsored and thus gasless.

- On the occasion that you’d like to use the Particle Network Omnichain Verifying Paymaster for Mainnets, you’ll need to deposit USDT on either Ethereum or BNB Chain within the Particle dashboard. This USDT will then automatically be converted as needed into the native token of the network you’re requesting (and qualifying for) sponsorship on.

- The Particle Network AA SDK automatically uses Biconomy’s Token Paymaster; transactions that request it will be able to leverage it without additional configuration.

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Initialization

To begin, before using the SDK, you’ll need to initialize it; without this, the setAAService within ParticleNetwork will fail or raise issues down the line.

You can initialize the SDK through AAService.initialize, which requires the following parameters:

Once AAService.initialize has been called, you’ll need to use ParticleNetwork.setAAService, passing in an instance of AAService. This will tell Particle Auth to use your smart account rather than your EOA. Either before or after doing this, you’ll also need to call aaService.enableAAMode.

AAService.initialize(name: .biconomyV1)

let aaService = AAService()
aaService.enableAAMode()

ParticleNetwork.setAAService(aaService)

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Examples of Utilization

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Disable AA Mode

If you’d like to disable AA mode (stop using account abstraction) after enabling it during the initialization process (through enableAAMode), then you’ll need to call aaService.disableAAMode, with aaService being an instance of AAService.

However, if you aren’t sure whether AA mode is enabled or not, you can call aaService.isAAModeEnable, which returns a Boolean representing this status.

E.g.:

aaService.disableAAMode() 

let isEnable = aayService.isAAModeEnable()

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Get Smart Account

You can also retrieve the address of the smart account, among other details, by calling the getSmartAccount method on aaService (which can be defined by ParticleNetwork.getAAService if needed), in which you can pass by (your Signer/owner address, which should be an EOA), and chainInfo, which should be a ChainInfo object representing the chain on which you’re querying account information. E.g.:

FieldTypeDescription
publicAddressStringEOA address.
chainInfoChainInfo?(Optional) default is current chainInfo.
let smartAccount = try await aaService.getSmartAccount(by: eoaAddress, chainInfo: chainInfo).value

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Send Transaction

Sending a transaction (UserOperation) is also quite simple, primarily just deviating in the fee mechanism being used for it. There are three ways to send transactions with the AA SDK:

The auth.evm.sendTransaction method, defined in ParticleAuthCore, is used to send a single transaction to the network.

The adapter.signAndSendTransaction method, defined in ConnectAdapter, is used to send a single transaction to the network.

The aaService.quickSendTransactions method, defined in ParticleAA, is used to send batched transactions within a single UserOperation.

auth.evm.sendTransaction takes the following parameters:

  • transaction, a stringified standard transaction object.
  • feeMode, the mechanism to be used for paying gas fees, can be:
    • .gasless, for sponsored transactions; this will happen automatically for Testnets, and will pull from your previously defined (or configured) Paymaster for Mainnets.
    • .native, paying for gas fees in a native token (such as ETH).
    • .token, paying for gas fees in an ERC-20 token (such as USDC), and thus takes one parameter:
      • feeQuote, to be used when leveraging a Token Paymaster.
  • Optionally, chainInfo: a ChainInfo object representing the chain on which this transaction will be executed.

adapter.signAndSendTransaction takes the following parameters:

  • publicAddress, the connected public address, if adapter.WalletType is .authCore, you can pass an empty string, for other walletTypes, you need pass a connected public address.
  • transaction, a stringified standard transaction object.
  • feeMode, the mechanism to be used for paying gas fees, can be:
    • .gasless, for sponsored transactions; this will happen automatically for Testnets, and will pull from your previously defined (or configured) Paymaster for Mainnets.
    • .native, paying for gas fees in a native token (such as ETH).
    • .token, paying for gas fees in an ERC-20 token (such as USDC), and thus takes one parameter:
      • feeQuote, to be used when leveraging a Token Paymaster.
  • Optionally, chainInfo: a ChainInfo object representing the chain on which this transaction will be executed.

Alternatively, for aaService.quickSendTransactions, the parameters will be the same with the following exceptions:

  • transactions being an array of transactions.
  • feeMode is same with upon.
  • messageSigner, which is the Signer/owner authenticating the transaction.
  • wholeFeeQuote, which for each feeMode should be passed with a complete fee quote object.
  • Optionally, chainInfo is same with upon.

E.g.:

// Gasless
let txHash = try await auth.evm.sendTransacton(transaction, feeMode: .gasless, chainInfo: chainInfo)

let txHash =  try await aaService.quickSendTransactions([transaction], feeMode: .gasless, messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value

// Native
let txHash = try await auth.evm.sendTransacton(transaction, feeMode: .native, chainInfo: chainInfo) 

let txHash = try await aaService.quickSendTransactions([transaction], feeMode: .native, messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value

// ERC-20 Token
let txHash = try await auth.evm.sendTransacton(transaction, feeMode: .token(feeQuote), chainInfo: chainInfo)

let txHash = try await aaService.quickSendTransactions([transaction], feeMode: .token(feeQuote), messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value

Implement MessageSigner protocol

class YourViewController {
  var publicAddress: String = ""
}

extension YourViewController: MessageSigner {
    func signMessage(_ message: String, chainInfo: ParticleNetworkBase.ParticleNetwork.ChainInfo?) -> RxSwift.Single<String> {
        // If you are using ParticleAuthService
        return Single<String>.fromAsync { [weak self] in
            guard let self = self else { throw ParticleNetwork.ResponseError(code: nil, message: "self is nil") }
            return try await self.evm.personalSign(message, chainInfo: chainInfo)
        }
        
        // If you are using ParticleConnectService
        // Get current adapter by walletType and publicAddress
        // Here we assume currentWalletType is Metamask
        
        let currentWalletType = WalletType.metaMask
        let adapters = ParticleConnect.getAllAdapters().filter {
            $0.walletType == currentWalletType
        }
        if let adapter = adapters.first {
            return adapter.signMessage(publicAddress: self.publicAddress, message: message)
        } else {
            return .error(NSError(domain: "", code: 0))
        }
    }
    
    func getEoaAddress() -> String {
        // If you are using ParticleAuthCore
        return auth.evm.getAddress() ?? ""
        
        // If you are using ParticleConnectService
        return self.publicAddress
    }
}
// Add this single extension to support converting rxswift function to combine function
extension Single {
    static func fromAsync<T>(_ fn: @escaping () async throws -> T) -> Single<T> {
        .create { observer in
            let task = Task {
                do { try await observer(.success(fn())) }
                catch { observer(.failure(error)) }
            }
            return Disposables.create { task.cancel() }
        }.observe(on: MainScheduler.instance)
    }
}

Check if you can send gasless/native/token.

extension YourViewController {
    func sendTransactionInAA() async throws {
        let aa = ParticleNetwork.getAAService()!
                
        let chainInfo = ParticleNetwork.getChainInfo()
        let eoaAddress = ""
        let transaction = ""
        let wholeFeeQuote = try await aa.rpcGetFeeQuotes(eoaAddress: eoaAddress, transactions: [transaction], chainInfo: chainInfo).value
            
        if wholeFeeQuote.gasless != nil {
            // There are two ways to sponsor transactions
            // 1, call adapter or ParticleAuthService, requires one transaction
            let txHash1 = try await auth.evm.sendTransaction(transaction, feeMode: .gasless, chainInfo: chainInfo)
            // 2, call AA, supports batched transactions, requires implementation of MessageSigner delegate.
            let txHash2 = try await aa.quickSendTransactions([transaction], feeMode: .gasless, messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value
        } else {
            // Gasless wouldn't be possible in this condition.
        }
            
        let nativeFeeQuote = AA.FeeQuote(json: wholeFeeQuote.native.feeQuote, tokenPaymasterAddress: nil)
        if nativeFeeQuote.isEnoughForPay {
            // There are two ways to send, pay token
            // 1, call adapter or ParticleAuthService, requires one transaction
            let txHash1 = try await auth.evm.signAndSendTransaction(transaction, feeMode: .native, chainInfo: chainInfo)
            // 2, call AA, supports batched transactions, requires implementation of MessageSigner delegate.
            let txHash2 = try await aa.quickSendTransactions([transaction], feeMode: .native, messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value
        } else {
            // User can't afford transaction
        }

        if let token = wholeFeeQuote.token {
            let tokenPaymasterAddress = token.tokenPaymasterAddress
            let tokenFeeQuotes = token.feeQuotes.map {
                AA.FeeQuote(json: $0, tokenPaymasterAddress: tokenPaymasterAddress)
            }.filter {
                // Filter out balance >= fee
                $0.isEnoughForPay
            }
            if tokenFeeQuotes.count > 0 {
                // Select a feeQuote, here we select the first one.
                let feeQuote = tokenFeeQuotes[0]
                // There are two ways to send, pay token
                // 1, call adapter or ParticleAuthService, requires one transaction
                let txHash1 = try await auth.evm.signAndSendTransaction(transaction, feeMode: .token(feeQuote), chainInfo: chainInfo)
                // 2, call AA, supports batched transactions, requires implementation of MessageSigner delegate.
                let txHash2 = try await aa.quickSendTransactions([transaction], feeMode: .token(feeQuote), messageSigner: self, wholeFeeQuote: wholeFeeQuote, chainInfo: chainInfo).value
            } else {
                // You can't select a token to pay
            }
        }
    }
}

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Manually Deploy Smart Account

An undeployed smart account will automatically be deployed upon the first transaction (UserOperation) it sends through the SDK (the deployment transaction is bundled/batched with the other). If you’d like to initiate deployment manually, bypassing automatic deployment, then you can use aaService.deployWalletContract, which will create, request signature for, and send a deployment transaction. This method requires messageSigner (the Signer of the transaction), and the feeMode of the deployment transaction.

The status of deployment can be retrieved with smartAccount.isDeploy, which takes an owner/Signer eoaAddress.

E.g.:

let isDeploy = try await aaService.isDeploy(eoaAddress: eoaAddress).value

aaService.deployWalletContract(messageSigner: signer, feeMode: .gasless)