Implement Webuntis HTTP Api and Display

lib/dataOld/incomingPacket.dart

@@ -0,0 +1,44 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:developer';
+
+import 'package:flutter/cupertino.dart';
+import 'package:marianum_mobile/dataOld/socketConnection.dart';
+
+class IncomingPacket extends ChangeNotifier {
+
+  String packetId;
+  bool useJsonDecode;
+
+  bool _isReceived = false;
+  bool get isReceived => _isReceived;
+  
+  IncomingPacket(this.packetId, {this.useJsonDecode = true}) {
+    SocketConnection.read.listen((event) {
+      if(event.startsWith("$packetId:")) {
+        _isReceived = true;
+
+        // THIS listener handles the incomming request
+        log("$packetId is handled!");
+        String content = event.split("$packetId:")[1];
+        handle(useJsonDecode ? jsonDecode(content) : content);
+      }
+      notifyListeners();
+    });
+  }
+
+  void invoke({Object? data, bool indicateLoading = false, bool allowNotifyListeners = true}) {
+    data = data ?? {};
+    log("$packetId is invoked with data: $data");
+    SocketConnection.write.add("$packetId:${jsonEncode(data)}");
+
+    if(indicateLoading) {
+      _isReceived = false;
+      if(allowNotifyListeners) notifyListeners();
+    }
+  }
+
+  void handle(dynamic data) {
+    log("Warning: $packetId packet listener is registered, but no handle is defined!");
+  }
+}