Renamed backend into auth_backend and added server_browser_backend implementation to replace Supabase.

server_browser_backend/lib/src/web_socket.dart

@@ -0,0 +1,126 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:server_browser_backend/src/server_entry.dart';
+
+class WebSocketServer {
+  static const String addEvent = 'add';
+  static const String removeEvent = 'remove';
+
+  final Map<String, ServerEntry> _entries = {};
+  final Set<WebSocket> _clients = {};
+
+  late HttpServer _server;
+
+  Future<void> start({int port = 8080}) async {
+    _server = await HttpServer.bind('0.0.0.0', port);
+    _listen();
+  }
+
+  Future<void> _listen() async {
+     await for (HttpRequest request in _server) {
+      if (WebSocketTransformer.isUpgradeRequest(request)) {
+        _handleWebSocketUpgrade(request);
+      } else {
+        request.response.statusCode = 404;
+        request.response.close();
+      }
+    }
+  }
+
+  Future<void> _handleWebSocketUpgrade(HttpRequest request) async {
+    final client = await WebSocketTransformer.upgrade(request);
+    _clients.add(client);
+    await _sendAllEntriesToClient(client);
+    client.listen(
+          (message) => _handleMessage(client, message),
+          onDone: () => _removeClient(client),
+          onError: (error) => _removeClient(client)
+    );
+  }
+
+  Future<void> _sendAllEntriesToClient(WebSocket client) async {
+    final message = {
+      'type': addEvent,
+      'data': _entries.values.map((entry) => entry.toJson()).toList()
+    };
+    client.add(json.encode(message));
+  }
+
+  void _handleMessage(WebSocket client, dynamic message) {
+    String? type;
+    try {
+      final data = jsonDecode(message);
+      type = data['type'];
+      final payload = data['data'];
+      switch (type) {
+        case addEvent:
+          final entry = ServerEntry.fromJson(payload);
+          _entries[entry.id] = entry;
+          _broadcastEvent(addEvent, entry.toJson());
+          break;
+        case removeEvent:
+          final deletedEntry = _entries.remove(payload);
+          if (deletedEntry != null) {
+            _broadcastEvent(removeEvent, {'id': deletedEntry.id});
+          }else {
+            _answer(client, removeEvent, "Invalid server entry");
+          }
+          break;
+        default:
+          _answer(client, type, 'Unknown type');
+          break;
+      }
+    } catch(error) {
+      _answer(client, type, error.toString());
+    }
+  }
+
+  void _broadcastEvent(String eventType, Map<String, dynamic> eventData) {
+    final message = {
+      'type': eventType,
+      'data': [
+        eventData
+      ]
+    };
+
+    final messageJson = json.encode(message);
+    final clientsToRemove = <WebSocket>[];
+
+    for (final client in _clients) {
+      try {
+        client.add(messageJson);
+      } catch (e) {
+        clientsToRemove.add(client);
+      }
+    }
+
+    for (final client in clientsToRemove) {
+      _removeClient(client);
+    }
+  }
+
+  void _removeClient(WebSocket client) {
+    client.close();
+    _clients.remove(client);
+  }
+
+  void _answer(WebSocket client, String? eventType, [String? error]) {
+    final message = {};
+    if(eventType != null) {
+      message['type'] = eventType;
+    }
+    if(error != null) {
+      message['success'] = false;
+      message['message'] = error;
+    }else {
+      message['success'] = true;
+    }
+    client.add(json.encode(message));
+  }
+
+  Future<void> stop() async {
+    await _server.close(force: true);
+    _clients.clear();
+  }
+}