Listen to WebSocket close events

lib/helpers/events_helper.dart

@@ -0,0 +1,32 @@
+import 'dart:async';
+
+import 'package:event_bus/event_bus.dart';
+
+/// Events helper
+///
+/// @author Pierre Hubert
+
+/// Main WebSocket closed
+class WSClosedEvent {}
+
+class EventsHelper {
+  static EventBus _mgr = EventBus();
+
+  /// Listen to event
+  ///
+  /// Do not use this method directly. You should instead prefer to use
+  /// [SafeState.listen] to handle safely widgets lifecycle...
+  ///
+  /// You can not register to global events
+  static StreamSubscription<T> on<T>(void onData(T event)) {
+    if (T == dynamic) throw Exception("Do not register to all events!");
+
+    final stream = _mgr.on<T>();
+    return stream.listen(onData);
+  }
+
+  /// Propagate an event
+  static void emit<T>(T event) {
+    _mgr.fire(event);
+  }
+}

lib/helpers/websocket_helper.dart

@@ -1,3 +1,4 @@
+import 'package:comunic/helpers/events_helper.dart';
 import 'package:comunic/models/api_request.dart';
 import 'package:comunic/models/config.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
@@ -28,7 +29,7 @@ class WebSocketHelper {
     // First, get an access token
     final token = await _getWsToken();
 
-    // Determine websocket URI
+    // Determine WebSocket URI
     final wsURL =
         "${(config().apiServerSecure ? "wss" : "ws")}://${config()
         .apiServerName}${config().apiServerUri}ws?token=$token";
@@ -48,7 +49,10 @@ class WebSocketHelper {
       },
 
       // Notify when the channel is closed
-      onDone: () => print("WS Channel closed"),
+      onDone: () {
+        print("WS Channel closed");
+        EventsHelper.emit(WSClosedEvent());
+      },
     );
   }
 }

lib/ui/widgets/init_widget.dart

@@ -1,5 +1,7 @@
+import 'package:comunic/helpers/events_helper.dart';
 import 'package:comunic/helpers/websocket_helper.dart';
 import 'package:comunic/ui/routes/main_route.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:flutter/material.dart';
 
@@ -17,7 +19,7 @@ class InitializeWidget extends StatefulWidget {
   _InitializeWidgetState createState() => _InitializeWidgetState();
 }
 
-class _InitializeWidgetState extends State<InitializeWidget> {
+class _InitializeWidgetState extends SafeState<InitializeWidget> {
   bool _error = false;
 
   @override
@@ -25,6 +27,9 @@ class _InitializeWidgetState extends State<InitializeWidget> {
     _tryConnect();
 
     super.initState();
+
+    // Listen to WebSocket close event
+    super.listen<WSClosedEvent>((e) => _tryConnect());
   }
 
   /// Try to connect to server

lib/ui/widgets/safe_state.dart

@@ -1,3 +1,6 @@
+import 'dart:async';
+
+import 'package:comunic/helpers/events_helper.dart';
 import 'package:flutter/material.dart';
 
 /// Little State hack to avoid issues
@@ -5,9 +8,26 @@ import 'package:flutter/material.dart';
 /// @author Pierre HUBERT
 
 abstract class SafeState<T extends StatefulWidget> extends State<T> {
+
+  final _subscriptions = List<StreamSubscription>();
+
+  @override
+  void dispose() {
+    // Close subscriptions
+    _subscriptions.forEach((f) => f.cancel());
+
+    super.dispose();
+  }
+
   @override
   void setState(fn) {
     if(mounted)
       super.setState(fn);
   }
+
+  /// Register to a new subscription
+  @protected
+  void listen<T>(void onEvent(T event)) {
+    _subscriptions.add(EventsHelper.on<T>(onEvent));
+  }
 }

pubspec.lock

@@ -106,6 +106,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.0.9"
+  event_bus:
+    dependency: "direct main"
+    description:
+      name: event_bus
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.1"
   flutter:
     dependency: "direct main"
     description: flutter

pubspec.yaml

@@ -72,6 +72,9 @@ dependencies:
   # Establish WebSocket connections
   web_socket_channel: ^1.1.0
 
+  # Events manager
+  event_bus: ^1.1.1
+
 dev_dependencies:
   flutter_test:
     sdk: flutter