What am I doing wrong while subscribing to AWS Appsync

[gorkemhacioglu]

Hello,
I am going to go crazy. Please help.

I can use mutations and queries there is no problem. But I fail to subscribe. No error at all. It just loops in

I/flutter (10679): Connected to websocket.
I/flutter (10679): Initialising connection
I/flutter (10679): Disconnected from websocket.
I/flutter (10679): Connected to websocket.
I/flutter (10679): Initialising connection
I/flutter (10679): Disconnected from websocket.

chat.dart:

void subscribeToNewMessages() {
    const String newMessageSubscription = "
  subscription OnNewMessage($conversationId: String!) {
    onNewMessage(conversationId: $conversationId) {
      messageId
      conversationId
      dateTime
      message
    }
  }
";

void _subscribe(String conversationId) {
  var subscription = graphQLClient
      .subscribe(
    SubscriptionOptions(
      document: gql(newMessageSubscription),
      variables: {'conversationId': conversationId},
    ),
  )
      .listen(
    (result) {
      if (result.hasException) {
        // Enhanced error logging
        print(
            'Subscription Exception for $conversationId: ${result.exception.toString()}');
        // Log specific error details if available
        if (result.exception?.linkException != null) {
          print('Link Exception: ${result.exception!.linkException}');
        }
        if (result.exception?.graphqlErrors != null &&
            result.exception!.graphqlErrors.isNotEmpty) {
          print(
              'GraphQL Errors: ${result.exception!.graphqlErrors.map((e) => e.message).join(', ')}');
        }
      } else if (result.data != null) {
        MessageDTO newMessage =
            MessageDTO.fromJson(result.data!['onNewMessage']);
        safeSetState(() {
          if (conversationId == widget.outgoingConversationId) {
            outgoingMessages.add(newMessage);
          } else {
            incomingMessages.add(newMessage);
          }
        });
      }
    },
    onError: (error) {
      print('Subscription error: $error');
    },
  );

  _messageSubscriptions.add(subscription);
}

// Subscribe to incoming conversation IDs
for (String id in widget.incomingConversationId) {
  _subscribe(id);
}

}

1. graphql_configuration.dart:

`import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:graphql_flutter/graphql_flutter.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';

class GraphQLConfiguration {
  late HttpLink httpLink;
  late WebSocketLink webSocketLink;
  late AuthLink authLink;
  late Link link;
  late ValueNotifier<GraphQLClient> client;

  ValueNotifier<GraphQLClient> getClient() => client;

  Future<void> dispose() async {
    client.dispose();
  }

  Future<void> initialize() async {
    await dotenv.load(fileName: "assets/config/.env");

    final String apiKey = 'myapikey';
    final String apiUrl = 'https://5u.appsync-api.us-east-2.amazonaws.com/graphql';
    String websocketUrl = 'wss://5u.appsync-realtime-api.us-east-2.amazonaws.com/graphql?header=<EncodedHeader>&payload=e30=';

    var header = r'''{
      "host": "5u.appsync-api.us-east-2.amazonaws.com",
      "x-api-key": "myapikey",
      'Sec-WebSocket-Protocol': GraphQLProtocol.graphqlWs
    }''';

    websocketUrl = websocketUrl.replaceFirst(
        '<EncodedHeader>', base64.encode(utf8.encode(header)));

    try {
      httpLink = HttpLink(
        apiUrl,
        defaultHeaders: {'x-api-key': apiKey},
      );

      authLink = AuthLink(
        getToken: () => 'Bearer $apiKey',
      );

      webSocketLink = WebSocketLink(
        websocketUrl,
        config: SocketClientConfig(
          autoReconnect: true,
          inactivityTimeout: const Duration(seconds: 60),
        ),
        subProtocol: GraphQLProtocol.graphqlWs,
      );

      link = Link.split(
        (request) => request.isSubscription,
        webSocketLink,
        authLink.concat(httpLink),
      );

      client = ValueNotifier(
        GraphQLClient(
          cache: GraphQLCache(store: InMemoryStore()),
          link: link,
        ),
      );
    } catch (e) {
      print('Failed to initialize GraphQL Client: $e');
    }
  }
}
`

[gorkemhacioglu]

I have used https://pub.dev/packages/amplify_flutter and solved the problem.