stack_wallet/lib/electrumx_rpc/rpc2.dart
2023-05-26 17:18:39 -06:00

261 lines
6.3 KiB
Dart

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;
}