untested protected rpc version

lib/electrumx_rpc/rpc2.dart

@@ -0,0 +1,261 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:mutex/mutex.dart';
+import 'package:stackwallet/utilities/logger.dart';
+
+// hacky fix to receive large jsonrpc responses
+class JsonRPC {
+  JsonRPC({
+    required this.host,
+    required this.port,
+    this.useSSL = false,
+    this.connectionTimeout = const Duration(seconds: 60),
+  });
+  final bool useSSL;
+  final String host;
+  final int port;
+  final Duration connectionTimeout;
+
+  final _requestMutex = Mutex();
+  final _JsonRPCRequestQueue _requestQueue = _JsonRPCRequestQueue();
+  Socket? _socket;
+  StreamSubscription<Uint8List>? _subscription;
+
+  void _dataHandler(List<int> data) {
+    _requestQueue.nextIncompleteReq.then((req) {
+      if (req != null) {
+        req.appendDataAndCheckIfComplete(data);
+
+        if (req.isComplete) {
+          _onReqCompleted(req);
+        }
+      } else {
+        Logging.instance.log(
+          "_dataHandler found a null req!",
+          level: LogLevel.Warning,
+        );
+      }
+    });
+  }
+
+  void _errorHandler(Object error, StackTrace trace) {
+    _requestQueue.nextIncompleteReq.then((req) {
+      if (req != null) {
+        req.completer.completeError(error, trace);
+        _onReqCompleted(req);
+      } else {
+        Logging.instance.log(
+          "_errorHandler found a null req!",
+          level: LogLevel.Warning,
+        );
+      }
+    });
+  }
+
+  void _doneHandler() {
+    Logging.instance.log(
+      "JsonRPC doneHandler: "
+      "connection closed to $host:$port, destroying socket",
+      level: LogLevel.Info,
+    );
+
+    disconnect(reason: "JsonRPC _doneHandler() called");
+  }
+
+  void _onReqCompleted(_JsonRPCRequest req) {
+    _requestQueue.remove(req).then((value) {
+      if (kDebugMode) {
+        print("Request removed from queue: $value");
+      }
+      // attempt to send next request
+      _sendNextAvailableRequest();
+    });
+  }
+
+  void _sendNextAvailableRequest() {
+    _requestQueue.nextIncompleteReq.then((req) {
+      if (req != null) {
+        // \r\n required by electrumx server
+        _socket!.write('${req.jsonRequest}\r\n');
+
+        // TODO different timeout length?
+        req.initiateTimeout(const Duration(seconds: 10));
+      } else {
+        Logging.instance.log(
+          "_sendNextAvailableRequest found a null req!",
+          level: LogLevel.Warning,
+        );
+      }
+    });
+  }
+
+  // TODO: non dynamic type
+  Future<dynamic> request(String jsonRpcRequest) async {
+    await _requestMutex.protect(() async {
+      if (_socket == null) {
+        Logging.instance.log(
+          "JsonRPC request: opening socket $host:$port",
+          level: LogLevel.Info,
+        );
+        await connect();
+      }
+    });
+
+    final req = _JsonRPCRequest(
+      jsonRequest: jsonRpcRequest,
+      completer: Completer<dynamic>(),
+    );
+
+    // if this is the only/first request then send it right away
+    await _requestQueue.add(
+      req,
+      onInitialRequestAdded: _sendNextAvailableRequest,
+    );
+
+    return req.completer.future.onError(
+      (error, stackTrace) => Exception(
+        "return req.completer.future.onError: $error",
+      ),
+    );
+  }
+
+  Future<void> disconnect({String reason = "none"}) async {
+    await _requestMutex.protect(() async {
+      await _subscription?.cancel();
+      _subscription = null;
+      _socket?.destroy();
+      _socket = null;
+
+      // clean up remaining queue
+      await _requestQueue.completeRemainingWithError(
+        "JsonRPC disconnect() called with reason: \"$reason\"",
+      );
+    });
+  }
+
+  Future<void> connect() async {
+    if (_socket != null) {
+      throw Exception(
+        "JsonRPC attempted to connect to an already existing socket!",
+      );
+    }
+
+    if (useSSL) {
+      _socket = await SecureSocket.connect(
+        host,
+        port,
+        timeout: connectionTimeout,
+        onBadCertificate: (_) => true,
+      ); // TODO do not automatically trust bad certificates
+    } else {
+      _socket = await Socket.connect(
+        host,
+        port,
+        timeout: connectionTimeout,
+      );
+    }
+
+    _subscription = _socket!.listen(
+      _dataHandler,
+      onError: _errorHandler,
+      onDone: _doneHandler,
+      cancelOnError: true,
+    );
+  }
+}
+
+class _JsonRPCRequestQueue {
+  final m = Mutex();
+
+  final List<_JsonRPCRequest> _rq = [];
+
+  Future<void> add(
+    _JsonRPCRequest req, {
+    VoidCallback? onInitialRequestAdded,
+  }) async {
+    return await m.protect(() async {
+      _rq.add(req);
+      if (_rq.length == 1) {
+        onInitialRequestAdded?.call();
+      }
+    });
+  }
+
+  Future<bool> remove(_JsonRPCRequest req) async {
+    return await m.protect(() async => _rq.remove(req));
+  }
+
+  Future<_JsonRPCRequest?> get nextIncompleteReq async {
+    return await m.protect(() async {
+      try {
+        return _rq.firstWhere((e) => !e.isComplete);
+      } catch (_) {
+        // no incomplete requests found
+        return null;
+      }
+    });
+  }
+
+  Future<void> completeRemainingWithError(
+    String error, {
+    StackTrace? stackTrace,
+  }) async {
+    await m.protect(() async {
+      for (final req in _rq) {
+        if (!req.isComplete) {
+          req.completer.completeError(Exception(error), stackTrace);
+        }
+      }
+      _rq.clear();
+    });
+  }
+
+  Future<bool> get isEmpty async {
+    return await m.protect(() async {
+      return _rq.isEmpty;
+    });
+  }
+}
+
+class _JsonRPCRequest {
+  final String jsonRequest;
+  final Completer<dynamic> completer;
+  final List<int> _responseData = [];
+
+  _JsonRPCRequest({required this.jsonRequest, required this.completer});
+
+  void appendDataAndCheckIfComplete(List<int> data) {
+    _responseData.addAll(data);
+    // 0x0A is newline
+    // https://electrumx-spesmilo.readthedocs.io/en/latest/protocol-basics.html
+    if (data.last == 0x0A) {
+      try {
+        final response = json.decode(String.fromCharCodes(_responseData));
+        completer.complete(response);
+      } catch (e, s) {
+        Logging.instance.log(
+          "JsonRPC json.decode: $e\n$s",
+          level: LogLevel.Error,
+        );
+        completer.completeError(e, s);
+      }
+    }
+  }
+
+  void initiateTimeout(Duration timeout) {
+    Future<void>.delayed(timeout).then((_) {
+      if (!isComplete) {
+        try {
+          throw Exception("_JsonRPCRequest timed out: $jsonRequest");
+        } catch (e, s) {
+          completer.completeError(e, s);
+        }
+      }
+    });
+  }
+
+  bool get isComplete => completer.isCompleted;
+}