tane/spike/block2_spike/lib/src/nostr_connection.dart
vjrj 2cafc7fc12 spike(block2): de-risk NIP-17 messaging + validate shared-connection shape
Extends the Block 2 spike to attack the highest-risk unbuilt piece (private
messaging) and to prove the Q2 architecture recommendation with running code:

- NostrConnection: one shared socket+key+sign+REQ/EOSE lifecycle. Refactored
  NostrOfferTransport onto it; added NostrMessageTransport — two thin contracts
  on ONE connection (the 'one connection, three interfaces' shape).
- NIP-44 v2 encryption (secp256k1 ECDH -> ChaCha20 + HMAC, length-hiding pad).
- NIP-17/NIP-59 gift-wrap: rumor(14) -> seal(13) -> wrap(1059, ephemeral key).
  Alice->Bob DM round-trips through the relay: encrypted, sender authenticated,
  and metadata-private (relay/eavesdropper sees only ciphertext, an ephemeral
  author and the recipient p-tag — Alice stays hidden).

Findings updated: NIP-17 risk drops Medium-High -> Medium (hardening, not
feasibility); next de-risking target is the web of trust. NIP-44 not yet
vector-verified (noted). 20 tests green, analyzer clean, Block 1 untouched.
2026-07-10 02:11:54 +02:00

95 lines
3.2 KiB
Dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'nostr_event.dart';
/// The ONE piece shared by every Nostr-backed transport (Q2 recommendation): a
/// single relay socket + the signing identity + the EVENT/OK and REQ/EOSE
/// lifecycle. `OfferTransport`, `MessageTransport` and a future `TrustTransport`
/// each sit on top of this — they share this *connection*, not a *contract*.
class NostrConnection {
NostrConnection._(this._socket, this.privateKeyHex, this.publicKeyHex) {
_socket.listen(_onData, onDone: _onDone);
}
final WebSocket _socket;
/// The derived (Q1) identity this connection signs with.
final String privateKeyHex;
final String publicKeyHex;
final _incoming = StreamController<List<dynamic>>.broadcast();
int _subCounter = 0;
static Future<NostrConnection> connect(
String relayUrl, {
required String privateKeyHex,
required String publicKeyHex,
}) async {
final socket = await WebSocket.connect(relayUrl);
return NostrConnection._(socket, privateKeyHex, publicKeyHex);
}
void _onData(dynamic d) => _incoming.add(jsonDecode(d as String) as List);
void _onDone() {
if (!_incoming.isClosed) _incoming.close();
}
/// Publishes an already-signed [event]; resolves with the relay's OK verdict.
Future<({bool accepted, String message})> publish(NostrEvent event) async {
final ok = _incoming.stream.firstWhere(
(m) => m[0] == 'OK' && m[1] == event.id,
);
_socket.add(jsonEncode(['EVENT', event.toJson()]));
final r = await ok.timeout(const Duration(seconds: 5));
return (accepted: r[2] as bool, message: r.length > 3 ? r[3] as String : '');
}
/// Streams events matching [filter] (live), until the caller cancels.
Stream<NostrEvent> subscribe(Map<String, dynamic> filter) {
final subId = 'sub${_subCounter++}';
late StreamController<NostrEvent> controller;
StreamSubscription? sub;
controller = StreamController<NostrEvent>(
onListen: () {
sub = _incoming.stream.listen((m) {
if (m[0] == 'EVENT' && m[1] == subId) {
controller.add(NostrEvent.fromJson(m[2] as Map<String, dynamic>));
}
});
_socket.add(jsonEncode(['REQ', subId, filter]));
},
onCancel: () async {
_socket.add(jsonEncode(['CLOSE', subId]));
await sub?.cancel();
},
);
return controller.stream;
}
/// Collects stored events matching [filter] up to EOSE, then closes the sub.
Future<List<NostrEvent>> reqOnce(Map<String, dynamic> filter) async {
final subId = 'once${_subCounter++}';
final results = <NostrEvent>[];
final done = Completer<void>();
final sub = _incoming.stream.listen((m) {
if (m[1] != subId) return;
if (m[0] == 'EVENT') {
results.add(NostrEvent.fromJson(m[2] as Map<String, dynamic>));
} else if (m[0] == 'EOSE' && !done.isCompleted) {
done.complete();
}
});
_socket.add(jsonEncode(['REQ', subId, filter]));
await done.future.timeout(const Duration(seconds: 5));
_socket.add(jsonEncode(['CLOSE', subId]));
await sub.cancel();
return results;
}
Future<void> close() async {
await _socket.close();
if (!_incoming.isClosed) await _incoming.close();
}
}