use Tor in subscribable client where applicable

lib/electrumx_rpc/subscribable_electrumx_client.dart

@@ -12,8 +12,13 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:socks_socket/socks_socket.dart';
 import 'package:stackwallet/electrumx_rpc/electrumx_client.dart';
+import 'package:stackwallet/exceptions/json_rpc/json_rpc_exception.dart';
+import 'package:stackwallet/services/event_bus/events/global/tor_connection_status_changed_event.dart';
+import 'package:stackwallet/services/tor_service.dart';
 import 'package:stackwallet/utilities/logger.dart';
+import 'package:stackwallet/utilities/prefs.dart';
 
 class ElectrumXSubscription {
   final StreamController<dynamic> _controller =
@@ -40,6 +45,7 @@ class SubscribableElectrumXClient {
   final Map<String, SocketTask> _tasks = {};
   Timer? _aliveTimer;
   Socket? _socket;
+  SOCKSSocket? _socksSocket;
   late final bool _useSSL;
   late final Duration _connectionTimeout;
   late final Duration _keepAlive;
@@ -49,6 +55,8 @@ class SubscribableElectrumXClient {
 
   void Function(bool)? onConnectionStatusChanged;
 
+  late Prefs _prefs;
+  late TorService _torService;
   SubscribableElectrumXClient({
     bool useSSL = true,
     this.onConnectionStatusChanged,
@@ -83,33 +91,51 @@ class SubscribableElectrumXClient {
   //   return client;
   // }
 
-  Future<void> connect({required String host, required int port}) async {
+  /// Connect to the server.
+  ///
+  /// If Tor is enabled, it will attempt to connect through Tor.
+  Future<void> connect({
+    required String host,
+    required int port,
+  }) async {
     try {
       await _socket?.close();
     } catch (_) {}
 
-    if (_useSSL) {
-      try {
-        _socket = await SecureSocket.connect(
-          host,
-          port,
-          timeout: _connectionTimeout,
-          onBadCertificate: (_) =>
-              true, // TODO do not automatically trust bad certificates.
-        );
-      } catch (e, s) {
+    if (!Prefs.instance.useTor) {
+      await connectClearnet(host, port);
+    } else {
+      // If we're supposed to use Tor...
+      if (_torService.status != TorConnectionStatus.connected) {
+        // ... but Tor isn't running...
+        if (!_prefs.torKillSwitch) {
+          // ... and the killswitch isn't set, then we'll connect clearnet.
           Logging.instance.log(
-            "Error connecting in SubscribableElectrumXClient"
-            "\nError: $e\nStack trace: $s",
-            level: LogLevel.Error);
+            "Tor preference set but Tor not enabled, no killswitch set, connecting to ElectrumX through clearnet",
+            level: LogLevel.Warning,
+          );
+          await connectClearnet(host, port);
+        } else {
+          // ... but if the killswitch is set, then let's try to start Tor.
+          await _torService.start();
+          // TODO [prio=low]: Attempt to restart Tor if needed.  Update Tor package for restart feature.
+
+          // Doublecheck that Tor is running.
+          if (_torService.status != TorConnectionStatus.connected) {
+            // If Tor still isn't running, then we'll throw an exception.
+            throw Exception(
+                "Tor preference and killswitch set but Tor not enabled, not connecting to ElectrumX");
+          }
+
+          // Connect via Tor.
+          await connectTor(host, port);
         }
       } else {
-      _socket = await Socket.connect(
-        host,
-        port,
-        timeout: _connectionTimeout,
-      );
+        // Connect via Tor.
+        await connectTor(host, port);
       }
+    }
+
     _updateConnectionStatus(true);
 
     _socket!.listen(
@@ -126,12 +152,127 @@ class SubscribableElectrumXClient {
     );
   }
 
+  /// Connect to the server directly.
+  Future<void> connectClearnet(String host, int port) async {
+    try {
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectClearnet(): "
+          "creating a socket to $host:$port (SSL $useSSL)...",
+          level: LogLevel.Info);
+
+      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,
+        );
+      }
+
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectClearnet(): "
+          "created socket to $host:$port...",
+          level: LogLevel.Info);
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient.connectClearnet: "
+          "failed to connect to $host (SSL: $useSSL)."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
+
+    return;
+  }
+
+  /// Connect to the server using the Tor service.
+  Future<void> connectTor(String host, int port) async {
+    // Get the proxy info from the TorService.
+    final proxyInfo = _torService.getProxyInfo();
+
+    try {
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "creating a SOCKS socket at $proxyInfo (SSL $useSSL)...",
+          level: LogLevel.Info);
+
+      // Create a socks socket using the Tor service's proxy info.
+      _socksSocket = await SOCKSSocket.create(
+        proxyHost: proxyInfo.host.address,
+        proxyPort: proxyInfo.port,
+        sslEnabled: useSSL,
+      );
+
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "created SOCKS socket at $proxyInfo...",
+          level: LogLevel.Info);
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient.connectTor(): "
+          "failed to create a SOCKS socket at $proxyInfo (SSL $useSSL)..."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
+
+    try {
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "connecting to SOCKS socket at $proxyInfo (SSL $useSSL)...",
+          level: LogLevel.Info);
+
+      await _socksSocket?.connect();
+
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "connected to SOCKS socket at $proxyInfo...",
+          level: LogLevel.Info);
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient.connectTor(): "
+          "failed to connect to SOCKS socket at $proxyInfo.."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
+
+    try {
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "connecting to $host:$port over SOCKS socket at $proxyInfo...",
+          level: LogLevel.Info);
+
+      await _socksSocket?.connectTo(host, port);
+
+      Logging.instance.log(
+          "SubscribableElectrumXClient.connectTor(): "
+          "connected to $host:$port over SOCKS socket at $proxyInfo",
+          level: LogLevel.Info);
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient.connectTor(): "
+          "failed to connect $host over tor proxy at $proxyInfo."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
+
+    return;
+  }
+
+  /// Disconnect from the server.
   Future<void> disconnect() async {
     _aliveTimer?.cancel();
     await _socket?.close();
+    await _socksSocket?.close();
     onConnectionStatusChanged = null;
   }
 
+  /// Format JSON request string.
   String _buildJsonRequestString({
     required String method,
     required String id,
@@ -254,8 +395,19 @@ class SubscribableElectrumXClient {
     final completer = Completer<dynamic>();
     _currentRequestID++;
     final id = _currentRequestID.toString();
+
+    try {
       _addTask(id: id, completer: completer);
 
+      if (_prefs.useTor) {
+        _socksSocket?.write(
+          _buildJsonRequestString(
+            method: method,
+            id: id,
+            params: params,
+          ),
+        );
+      } else {
         _socket?.write(
           _buildJsonRequestString(
             method: method,
@@ -263,10 +415,19 @@ class SubscribableElectrumXClient {
             params: params,
           ),
         );
-
-    return completer.future;
       }
 
+      return completer.future;
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient._call: "
+          "failed to request $method with id $id."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
+  }
+
+  /// Write call to socket with timeout.
   Future<dynamic> _callWithTimeout({
     required String method,
     List<dynamic> params = const [],
@@ -275,8 +436,19 @@ class SubscribableElectrumXClient {
     final completer = Completer<dynamic>();
     _currentRequestID++;
     final id = _currentRequestID.toString();
+
+    try {
       _addTask(id: id, completer: completer);
 
+      if (_prefs.useTor) {
+        _socksSocket?.write(
+          _buildJsonRequestString(
+            method: method,
+            id: id,
+            params: params,
+          ),
+        );
+      } else {
         _socket?.write(
           _buildJsonRequestString(
             method: method,
@@ -284,6 +456,7 @@ class SubscribableElectrumXClient {
             params: params,
           ),
         );
+      }
 
       Timer(timeout, () {
         if (!completer.isCompleted) {
@@ -294,30 +467,51 @@ class SubscribableElectrumXClient {
       });
 
       return completer.future;
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient._callWithTimeout: "
+          "failed to request $method with id $id (timeout $timeout)."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
   }
 
   ElectrumXSubscription _subscribe({
-    required String taskId,
+    required String id,
     required String method,
     List<dynamic> params = const [],
   }) {
-    // try {
+    try {
       final subscription = ElectrumXSubscription();
-    _addSubscriptionTask(id: taskId, subscription: subscription);
+      _addSubscriptionTask(id: id, subscription: subscription);
       _currentRequestID++;
-    _socket?.write(
+
+      if (_prefs.useTor) {
+        _socksSocket?.write(
           _buildJsonRequestString(
             method: method,
-        id: taskId,
+            id: id,
             params: params,
           ),
         );
+      } else {
+        _socket?.write(
+          _buildJsonRequestString(
+            method: method,
+            id: id,
+            params: params,
+          ),
+        );
+      }
 
       return subscription;
-    // } catch (e, s) {
-    //   Logging.instance.log("SubscribableElectrumXClient _subscribe: $e\n$s", level: LogLevel.Error);
-    //   return null;
-    // }
+    } catch (e, s) {
+      final String msg = "SubscribableElectrumXClient._subscribe: "
+          "failed to subscribe to $method with id $id."
+          "\nError: $e\nStack trace: $s";
+      Logging.instance.log(msg, level: LogLevel.Fatal);
+      throw JsonRpcException(msg);
+    }
   }
 
   /// Ping the server to ensure it is responding
@@ -335,7 +529,7 @@ class SubscribableElectrumXClient {
   /// Subscribe to a scripthash to receive notifications on status changes
   ElectrumXSubscription subscribeToScripthash({required String scripthash}) {
     return _subscribe(
-      taskId: 'blockchain.scripthash.subscribe:$scripthash',
+      id: 'blockchain.scripthash.subscribe:$scripthash',
       method: 'blockchain.scripthash.subscribe',
       params: [scripthash],
     );
@@ -347,7 +541,7 @@ class SubscribableElectrumXClient {
   ElectrumXSubscription subscribeToBlockHeaders() {
     return _tasks["blockchain.headers.subscribe"]?.subscription ??
         _subscribe(
-          taskId: "blockchain.headers.subscribe",
+          id: "blockchain.headers.subscribe",
           method: "blockchain.headers.subscribe",
           params: [],
         );