TrustSDK

Getting Started

The TrustSDK lets you sign Ethereum transactions and messages so that you can bulid a native DApp without having to worry about keys or wallets. Follw these instructions to integrate TrustSDK in your native DApp.

Demo

Installation

TrustSDK is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'TrustSDK'

Run pod install.

Configuration

Follow the next steps to configure TrustSDK in your app.

Schema Configuration

Open Xcode an click on your project. Go to the ‘Info’ tab and expand the ‘URL Types’ group. Click on the + button to add a new scheme. Enter a custom scheme name in ‘URL Scemes’.

Initialization

Open AppDelegate.swift file and initialize TrustSDK inapplication(_:didFinishLaunchingWithOptions:) method:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    TrustSDK.initialize(with: TrustSDK.Configuration(scheme: "trustexample"))
    return true
}

Handling Callbacks

Let TrustSDK capture deeplink responses by calling TrustSDK in application(_:open:options:) method:

func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
  return TrustSDK.application(app, open: url, options: options)
}

API

To use TrustSDK you have to import TrustSDK and TrustWalletCore modules.

Sign Transaction

TrustSDK comes with an easy to use generic API to sign transactions. Each blockchain accept a SigningInput object and respond with a SigningOutput that can be broadcasted directly to the node. Each input and output object is a Swift implementation of wallet-core’s protobuf messages. To sign an Ethereum transaction you have the following SigningInput:

let input = EthereumSigningInput.with {
    $0.toAddress = "0x3D60643Bf82b928602bce34EE426a7d392157b69"
    $0.chainID = BigInt("1").serialize()!
    $0.nonce = BigInt("464").serialize()!
    $0.gasPrice = BigInt("11500000000").serialize()!
    $0.gasLimit = BigInt("21000").serialize()!
    $0.amount = BigInt("1000000000000000").serialize()!
}

TrustSDK comes with some handy extensions to handle Data and BigInt serialization with ease.

Once you have the input defined, you just have to call the blockchain signer to sign the transaction:

TrustSDK.signers.ethereum.sign(input: input) { result in
  switch result {
  case .success(let output):
      // Handle the signing output
  case .failure(let error):
      // Handle failres like user rejections
  }
}

Sign Messages

To request signing message, you have to encode or hash your message in hex-encoded format first, and then call sign(message:) from TrustSDK.signers, below is an Ethereum example message:

let data = Data("Some message".utf8)
let message = Data("\u{19}Ethereum Signed Message:\n\(data.count)".utf8) + data
let hash = message.sha3(.keccak256)
TrustSDK.signers.ethereum.sign(message: hash) { result in
    switch result {
    case .success(let signature):
        // Handle the signature
    case .failure(let error):
        // Handle failure
    }
}

Get Addresses

To get users addresses, you just need to call getAccounts(for:) directly from TrustSDK and pass an array of CoinType:

TrustSDK.getAccounts(for: [.ethereum, .bitcoin]) { result in
    switch result {
    case .success(let addresses):
        // Handle the address array
    case .failure(let error):
        // Handle failure
    }
}

Wallet Developers

If your wallet already uses TrustWalletCore and want to integrate with TrustSDK you just need to follow the steps below:

Install WalletSDK

Add the following line to your Podfile:

pod 'TrustSDK/Wallet'

Run pod install.

Handling TrustSDK Commands

Import TrustSDK and implement WalletSDKRequestHandler.handle(request:callback:). Commands must handled asyncronously, once
finished, your implementation have to call the callback parameter with the command’s response.

class WalletSDKRequestHandlerImplementation: WalletSDKRequestHandler {
  func handle(request: WalletSDK.Request, callback: @escaping ((WalletSDK.Response) -> Void)) {
    switch request.command {
    case .getAccounts(let coins):
      // Handle get accoutns command
      let accounts = ...
      callback(.accounts(accounts))
    case .sign(let coin, let input):
      // Handle sign command
      let output = ...
      callback(.sign(coin: coin, output: output))
    }    
    // You can respond with a failure response in case of exception
    callback(.failure(.unknown))
  }
}

On your app initialization method, set the handler implemention WalletSDK.handler then let WalletSDK handle deeplinks by calling it in application(_:open:options:) method:

func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
  return WalletSDK.application(app, open: url, options: options)
}

If you have your app already handles deeplinks, or you have to parse WalletSDK.Request struct by yourself and dispatch is
using WalletSDK.dispatch(request:) method.

Supporting Your Wallet

Once you have WalletSDK configured for your wallet, tell dApp developers to set thewalletApp attribute in TrustSDK.Configureation with your wallet’s scheme and installURL:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let wallet = WalletApp(
      scheme: "walletscheme",
      installURL: URL(string: "https://apps.apple.com/app/walletapp")!
    )
    TrustSDK.initialize(with: TrustSDK.Configuration(scheme: "trustexample", walletApp: wallet))
    return true
}

Example

Trust SDK includes an example project with the above code. To run the example project clone the repo and run pod install from the Example directory. Open TrustSDK.xcworkspace and run. Make sure that you have Trust Wallet installed on the device or simulator to test the full callback flow.

Author

• Leone Parise
• Viktor Radchenko

License

TrustSDK is available under the MIT license. See the LICENSE file for more info.