feat: auto-reconnect on network change (WiFi/cellular/VPN switch)

Matthias Nott

2026-04-01 3e19d6917ff245863be43a39a76daa7010ecda6f

feat: auto-reconnect on network change (WiFi/cellular/VPN switch)

 ios/Podfile.lock
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@@ -5,6 +5,8 @@
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   - bonsoir_darwin (0.0.1):
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     - Flutter
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     - FlutterMacOS
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+  - connectivity_plus (0.0.1):
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+    - Flutter
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   - device_info_plus (0.0.1):
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     - Flutter
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   - DKImagePickerController/Core (4.3.9):
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@@ -70,6 +72,7 @@
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 DEPENDENCIES:
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   - audioplayers_darwin (from `.symlinks/plugins/audioplayers_darwin/darwin`)
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   - bonsoir_darwin (from `.symlinks/plugins/bonsoir_darwin/darwin`)
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+  - connectivity_plus (from `.symlinks/plugins/connectivity_plus/ios`)
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   - device_info_plus (from `.symlinks/plugins/device_info_plus/ios`)
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   - file_picker (from `.symlinks/plugins/file_picker/ios`)
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   - Flutter (from `Flutter`)
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@@ -95,6 +98,8 @@
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     :path: ".symlinks/plugins/audioplayers_darwin/darwin"
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   bonsoir_darwin:
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     :path: ".symlinks/plugins/bonsoir_darwin/darwin"
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+  connectivity_plus:
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+    :path: ".symlinks/plugins/connectivity_plus/ios"
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   device_info_plus:
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     :path: ".symlinks/plugins/device_info_plus/ios"
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   file_picker:
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@@ -123,6 +128,7 @@
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 SPEC CHECKSUMS:
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   audioplayers_darwin: 835ced6edd4c9fc8ebb0a7cc9e294a91d99917d5
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   bonsoir_darwin: 29c7ccf356646118844721f36e1de4b61f6cbd0e
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+  connectivity_plus: cb623214f4e1f6ef8fe7403d580fdad517d2f7dd
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   device_info_plus: 21fcca2080fbcd348be798aa36c3e5ed849eefbe
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   DKImagePickerController: 946cec48c7873164274ecc4624d19e3da4c1ef3c
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   DKPhotoGallery: b3834fecb755ee09a593d7c9e389d8b5d6deed60
 lib/services/mqtt_service.dart
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 import 'package:crypto/crypto.dart';
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 import 'package:bonsoir/bonsoir.dart';
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+import 'package:connectivity_plus/connectivity_plus.dart';
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 import 'package:flutter/foundation.dart';
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 import 'package:flutter/widgets.dart';
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 import 'package:path_provider/path_provider.dart' as pp;
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@@ -50,6 +51,8 @@
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   bool _intentionalClose = false;
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   String? _clientId;
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   String? _lastDiscoveredHost;
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+  StreamSubscription? _connectivitySub;
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+  List<ConnectivityResult>? _lastConnectivity;
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   StreamSubscription? _updatesSub;
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   // Message deduplication
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@@ -103,6 +106,36 @@
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     _intentionalClose = false;
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     _setStatus(ConnectionStatus.connecting);
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+
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+    // Start listening for network changes (WiFi↔cellular, VPN connect/disconnect)
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+    _connectivitySub ??= Connectivity().onConnectivityChanged.listen((results) {
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+      if (_lastConnectivity != null && !_intentionalClose) {
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+        final changed = results.length != _lastConnectivity!.length ||
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+            !results.every((r) => _lastConnectivity!.contains(r));
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+        if (changed) {
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+          _mqttLog('MQTT: network changed: ${results.map((r) => r.name).join(",")} — forcing reconnect');
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+          // Force disconnect and reconnect on new network
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+          final client = _client;
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+          if (client != null) {
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+            _intentionalClose = true;
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+            client.autoReconnect = false;
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+            try { client.disconnect(); } catch (_) {}
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+            _client = null;
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+            _updatesSub?.cancel();
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+            _updatesSub = null;
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+            _intentionalClose = false;
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+          }
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+          _lastDiscoveredHost = null; // Clear cached discovery — subnet may have changed
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+          connectedHost = null;
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+          connectedVia = null;
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+          _setStatus(ConnectionStatus.reconnecting);
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+          Future.delayed(const Duration(milliseconds: 500), () {
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+            if (!_intentionalClose) connect();
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+          });
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+        }
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+      }
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+      _lastConnectivity = results;
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+    });
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     // Load trusted cert fingerprint for TOFU verification
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     if (_trustedFingerprint == null) await _loadTrustedFingerprint();
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@@ -724,6 +757,8 @@
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     _intentionalClose = true;
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     _updatesSub?.cancel();
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     _updatesSub = null;
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+    _connectivitySub?.cancel();
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+    _connectivitySub = null;
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     try {
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       _client?.disconnect();
 macos/Flutter/GeneratedPluginRegistrant.swift
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 import audioplayers_darwin
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 import bonsoir_darwin
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+import connectivity_plus
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 import device_info_plus
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 import file_picker
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 import file_selector_macos
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 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
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   AudioplayersDarwinPlugin.register(with: registry.registrar(forPlugin: "AudioplayersDarwinPlugin"))
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   SwiftBonsoirPlugin.register(with: registry.registrar(forPlugin: "SwiftBonsoirPlugin"))
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+  ConnectivityPlusPlugin.register(with: registry.registrar(forPlugin: "ConnectivityPlusPlugin"))
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   DeviceInfoPlusMacosPlugin.register(with: registry.registrar(forPlugin: "DeviceInfoPlusMacosPlugin"))
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   FilePickerPlugin.register(with: registry.registrar(forPlugin: "FilePickerPlugin"))
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   FileSelectorPlugin.register(with: registry.registrar(forPlugin: "FileSelectorPlugin"))
 pubspec.lock
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       url: "https://pub.dev"
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     source: hosted
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     version: "1.19.1"
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+  connectivity_plus:
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+    dependency: "direct main"
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+    description:
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+      name: connectivity_plus
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+      sha256: b8fe52979ff12432ecf8f0abf6ff70410b1bb734be1c9e4f2f86807ad7166c79
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+      url: "https://pub.dev"
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+    source: hosted
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+    version: "7.1.0"
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+  connectivity_plus_platform_interface:
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+    dependency: transitive
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+    description:
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+      name: connectivity_plus_platform_interface
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+      sha256: "3c09627c536d22fd24691a905cdd8b14520de69da52c7a97499c8be5284a32ed"
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+      url: "https://pub.dev"
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+    source: hosted
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+    version: "2.1.0"
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   cross_file:
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     dependency: transitive
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     description:
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       url: "https://pub.dev"
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     source: hosted
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     version: "0.17.6"
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+  nm:
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+    dependency: transitive
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+    description:
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+      name: nm
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+      sha256: "2c9aae4127bdc8993206464fcc063611e0e36e72018696cd9631023a31b24254"
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+      url: "https://pub.dev"
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+    source: hosted
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+    version: "0.5.0"
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   objective_c:
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     dependency: transitive
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     description:
 pubspec.yaml
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   crypto: ^3.0.7
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   push: ^3.3.3
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   flutter_app_badger: ^1.5.0
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+  connectivity_plus: ^7.1.0
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 dev_dependencies:
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   flutter_test:
 windows/flutter/generated_plugin_registrant.cc
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 #include <audioplayers_windows/audioplayers_windows_plugin.h>
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 #include <bonsoir_windows/bonsoir_windows_plugin_c_api.h>
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+#include <connectivity_plus/connectivity_plus_windows_plugin.h>
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 #include <file_selector_windows/file_selector_windows.h>
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 #include <flutter_secure_storage_windows/flutter_secure_storage_windows_plugin.h>
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 #include <permission_handler_windows/permission_handler_windows_plugin.h>
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       registry->GetRegistrarForPlugin("AudioplayersWindowsPlugin"));
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   BonsoirWindowsPluginCApiRegisterWithRegistrar(
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       registry->GetRegistrarForPlugin("BonsoirWindowsPluginCApi"));
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+  ConnectivityPlusWindowsPluginRegisterWithRegistrar(
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+      registry->GetRegistrarForPlugin("ConnectivityPlusWindowsPlugin"));
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   FileSelectorWindowsRegisterWithRegistrar(
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       registry->GetRegistrarForPlugin("FileSelectorWindows"));
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   FlutterSecureStorageWindowsPluginRegisterWithRegistrar(
 windows/flutter/generated_plugins.cmake
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 list(APPEND FLUTTER_PLUGIN_LIST
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   audioplayers_windows
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   bonsoir_windows
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+  connectivity_plus
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   file_selector_windows
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   flutter_secure_storage_windows
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   permission_handler_windows