A dart package that simplifies the integration of Nostr Wallet Connect protocol into client applications.

Overview

NWC (Nostr Wallet Connect) is a Dart package. It offers a straightforward solution for developers aiming to integrate their app with the NWC protocol, enabling seamless access to a remote Lightning wallet through a standardized protocol. The protocol specifications are defined in NIP47, and this package is created to adhere to those specifications.

Features

• Simple Integration: Easily implement the NWC protocol into your Nostr client or Flutter app with minimal effort.
• Standardized Protocol: Follows the specifications outlined in NIP47 for consistent and reliable functionality.
• Secure Communication: Ensures secure communication between your client and the remote Lightning wallet (NIP04 implemented).

Installation

Add the following line to your pubspec.yaml:

dependencies:
  nwc: ^1.0.0

Then run:

$ flutter pub get

Usage

Initializing the "nwc" Package

To begin using the "nwc" package, you first need to import it into your Dart project. Then, instantiate the NWC class:

import 'package:nwc/nwc.dart';

final nwc = NWC();

Parsing Connection URI

The parseNostrConnectUri method is used to parse the connection URI, extracting essential information such as pubkey, relay, secret and lud16 for communication with the remote Lightning wallet:

final parsedUri = nwc.nip47.parseNostrConnectUri(connectionURI);

Initializing Relay Service

Before interacting with the remote wallet, you need to initialize the relay service. This step ensures proper communication channels are established:

await nwc.relaysService.init(relaysUrl: [parsedUri.relay]);

Subscribing to Events

You can subscribe to specific events from the remote wallet using filters. This allows your application to react to relevant updates. :

final subToFilter = Request(
  filters: [
    Filter(
      kinds: [23195], // 23195 is registered for NIP47 response
      authors: [parsedUri.pubkey], // Specifying the pubkey of the wallet service
      since: DateTime.now(), // Specify a timestamp to start filtering events
    ),
  ],
);

final nostrStream = nwc.relaysService.startEventsSubscription(
  request: subToFilter,
  onEose: (relay, eose) =>
      print('[+] subscriptionId: ${eose.subscriptionId}, relay: $relay'),
);

Listening to Event Stream

Once subscribed, you can listen to the event stream and react accordingly. Events are decrypted and processed based on the NIP04 protocol:

nostrStream.stream.listen((Event event) {
  if (event.kind == 23195 && event.content != null) {
    try {
      final decryptedContent = nwc.nip04.decrypt(
        parsedUri.secret,
        parsedUri.pubkey,
        event.content!,
      );

      final content = nwc.nip47.parseResponseResult(decryptedContent);

      // Handle different types of events accordingly
      if (content.resultType == NWCResultType.get_balance) {
        final result = content.result as Get_Balance_Result;
        print('[+] Balance: ${result.balance} msat');
      } else if (content.resultType == NWCResultType.make_invoice) {
        final result = content.result as Make_Invoice_Result;
        print('[+] Invoice: ${result.invoice}');
      } else if (content.resultType == NWCResultType.pay_invoice) {
        final result = content.result as Pay_Invoice_Result;
        print('[+] Preimage: ${result.preimage}');
      } else if (content.resultType == NWCResultType.error) {
        final result = content.result as NWC_Error_Result;
        print('[+] Preimage: ${result.errorMessage}');
      } else {
        print('[+] content: $decryptedContent');
      }
    } catch (e) {
      if (e is DecipherFailedException) {
        print('$e');
      }
    }
  }
});

Sending Events

Finally, you can send events to the remote wallet using the appropriate commands defined in NIP47. This allows you to perform actions such as fetching balances, generating invoices, or making payments:

final message = {"method": "get_balance"};

final content = nwc.nip04.encrypt(
  parsedUri.secret,
  parsedUri.pubkey,
  jsonEncode(message),
);

final request = Event.fromPartialData(
  kind: 23194,
  content: content,
  tags: [['p', parsedUri.pubkey]],
  createdAt: DateTime.now(),
  keyPairs: KeyPairs(private: parsedUri.secret),
);

final okCommand = await nwc.relaysService.sendEventToRelays(
  request,
  timeout: const Duration(seconds: 3),
);

print('[+] getBalance() => okCommand: $okCommand');

By following these steps, you can effectively integrate the "nwc" package into your flutter app, enabling seamless communication with remote Lightning wallets through the NWC protocol.

Contributing

Contributions are welcome! If you have suggestions, feature requests, or bug reports, please open an issue or submit a pull request.

License

This package is licensed under the MIT License - see the LICENSE file for details.