Overview

WalletConnect Dart v2 library for Flutter, heavily inspired by the WalletConnect V2 Javascript Monorepo.

Original work for this library is attributed to Eucalyptus Labs and Sterling Long for Koala Wallet, a wallet built for the Kadena blockchain.

To Use

Pair, Approve, and Sign/Auth

dApp Flow

// To create both an Auth and Sign API, you can use the Web3App
// If you just need one of the other, replace Web3App with SignClient or AuthClient
// SignClient wcClient = await SignClient.createInstance(
// AuthClient wcClient = await AuthClient.createInstance(
Web3App wcClient = await Web3App.createInstance(
  core: Core(
    relayUrl: 'wss://relay.walletconnect.com', // The relay websocket URL
    projectId: '123',
  ),
  metadata: PairingMetadata(
    name: 'dApp (Requester)',
    description: 'A dapp that can request that transactions be signed',
    url: 'https://walletconnect.com',
    icons: ['https://avatars.githubusercontent.com/u/37784886'],
  ),
);

// For a dApp, you would connect with specific parameters, then display
// the returned URI.
ConnectResponse resp = await wcClient.connect(
  requiredNamespaces: {
    'eip155': RequiredNamespace(
      chains: ['eip155:1'], // Ethereum chain
      methods: ['eth_signTransaction'], // Requestable Methods
    ),
    'kadena': RequiredNamespace(
      chains: ['kadena:mainnet01'], // Kadena chain
      methods: ['kadena_quicksign_v1'], // Requestable Methods
    ),
  }
)
Uri? uri = resp.uri;

// Once you've display the URI, you can wait for the future, and hide the QR code once you've received session data
final SessionData session = await resp.session.future;

// Now that you have a session, you can request signatures
final dynamic signResponse = await wcClient.request(
  topic: session.topic,
  chainId: 'eip155:1',
  request: SessionRequestParams(
    method: 'eth_signTransaction',
    params: 'json serializable parameters',
  ),
);
// Unpack, or use the signResponse.
// Structure is dependant upon the JSON RPC call you made.


// You can also request authentication
final AuthRequestResponse authReq = await wcClient.requestAuth(
  params: AuthRequestParams(
    aud: 'http://localhost:3000/login',
    domain: 'localhost:3000',
    chainId: 'eip155:1',
    nonce: AuthUtils.generateNonce(),
    statement: 'Sign in with your wallet!',
  ),
  pairingTopic: resp.pairingTopic,
);

// Await the auth response using the provided completer
final AuthResponse authResponse = await authResponse.completer.future;
if (authResponse.result != null) {
  // Having a result means you have the signature and it is verified.
}
else {
  // Otherwise, you might have gotten a WalletConnectError if there was un issue verifying the signature.
  final WalletConnectError? error = authResponse.error;
  // Of a JsonRpcError if something went wrong when signing with the wallet.
  final JsonRpcError? error = authResponse.jsonRpcError;
}


// You can also respond to events from the wallet, like session events
wcClient.onSessionEvent.subscribe((SessionEvent? session) {
  // Do something with the event
});
wcClient.registerEventHandler(
  namespace: 'kadena',
  method: 'kadena_transaction_updated',
);

Wallet Flow

Web3Wallet wcClient = await Web3Wallet.createInstance(
  core: Core(
    relayUrl: 'wss://relay.walletconnect.com', // The relay websocket URL
    projectId: '123',
  ),
  metadata: PairingMetadata(
    name: 'Wallet (Responder)',
    description: 'A wallet that can be requested to sign transactions',
    url: 'https://walletconnect.com',
    icons: ['https://avatars.githubusercontent.com/u/37784886'],
  ),
);

// For a wallet, setup the proposal handler that will display the proposal to the user after the URI has been scanned.
late int id;
wcClient.onSessionProposal.subscribe((SessionProposal? args) async {
  // Handle UI updates using the args.params
  // Keep track of the args.id for the approval response
  id = args!.id;
})

// Also setup the methods and chains that your wallet supports
wcClient.onSessionRequest.subscribe((SessionRequestEvent? request) async {
  // You can respond to requests in this manner
  await clientB.respondSessionRequest(
    topic: request.topic,
    response: JsonRpcResponse<String>(
      id: request.id,
      result: 'Signed!',
    ),
  );
});
wcClient.registerRequestHandler(
  namespace: 'kadena',
  method: 'kadena_sign',
);

// Setup the auth handling
clientB.onAuthRequest.subscribe((AuthRequest? args) async {

  // This is where you would 
  // 1. Store the information to be signed
  // 2. Display to the user that an auth request has been received

  // You can create the message to be signed in this manner
  String message = clientB.formatAuthMessage(
    iss: TEST_ISSUER_EIP191,
    cacaoPayload: CacaoRequestPayload.fromPayloadParams(
      args!.payloadParams,
    ),
  );
});

// Then, scan the QR code and parse the URI, and pair with the dApp
// On the first pairing, you will immediately receive onSessionProposal and onAuthRequest events.
Uri uri = Uri.parse(scannedUriString);
final PairingInfo pairing = await wcClient.pair(uri: uri);

// Present the UI to the user, and allow them to reject or approve the proposal
final walletNamespaces = {
  'eip155': Namespace(
    accounts: ['eip155:1:abc'],
    methods: ['eth_signTransaction'],
  ),
  'kadena': Namespace(
    accounts: ['kadena:mainnet01:abc'],
    methods: ['kadena_sign_v1', 'kadena_quicksign_v1'],
    events: ['kadena_transaction_updated'],
  ),
}
await wcClient.approveSession(
  id: id,
  namespaces: walletNamespaces // This will have the accounts requested in params
);
// Or to reject...
// Error codes and reasons can be found here: https://docs.walletconnect.com/2.0/specs/clients/sign/error-codes
await wcClient.rejectSession(
  id: id,
  reason: Errors.getSdkError(Errors.USER_REJECTED_SIGN),
);

// For auth, you can do the same thing: Present the UI to them, and have them approve the signature.
// Then respond with that signature
String sig = 'your sig here';
await wcClient.respondAuthRequest(
  id: args.id,
  iss: 'did:pkh:eip155:1:0x06C6A22feB5f8CcEDA0db0D593e6F26A3611d5fa',
  signature: CacaoSignature(t: CacaoSignature.EIP191, s: sig),
);
// Or rejected
// Error codes and reasons can be found here: https://docs.walletconnect.com/2.0/specs/clients/sign/error-codes
await wcClient.respondAuthRequest(
  id: args.id,
  error: Errors.getSdkError(Errors.USER_REJECTED_AUTH),
);

// You can also emit events for the dApp
await wcClient.emitSessionEvent(
  topic: sessionTopic,
  chainId: 'eip155:1',
  event: SessionEventParams(
    name: 'chainChanged',
    data: 'a message!',
  ),
);

// Finally, you can disconnect
await wcClient.disconnectSession(
  topic: pairing.topic,
  reason: Errors.getSdkError(Errors.USER_DISCONNECTED),
);

To Build

Example project and dapp
Reduce number of crypto libraries used for encryption, shared key, etc.
Additional APIs defined by WalletConnect

To Test

Run tests using flutter test. Expected flutter version is: >3.3.10

Commands Run in CI

flutter analyze
dart format --output=none --set-exit-if-changed .

Useful Commands

flutter pub run build_runner build --delete-conflicting-outputs - Regenerates JSON Generators
flutter doctor -v - get paths of everything installed.
flutter pub get
flutter upgrade
flutter clean
flutter pub cache clean
flutter pub deps
flutter pub run dependency_validator - show unused dependencies and more
dart format lib/* -l 120
flutter analyze

bobwith2bees/WalletConnectFlutterV2