Flutter app login after a logout PostgresSQLException - postgresql

Question

I'm working on a Flutter app using Riverpod for the state management and Postgres for the database. I try to do a simple thing: display a message in the home screen with the nickname of the current user. When I logout and login to check if my feature works, my user is null and my console display a PostgresSQLException :
PostgreSQLSeverity.error : Attempting to reopen a closed connection. Create a instance instead.
Any idea where I made a mistake?
My user_repository:
PostgreSQLConnection connection = PostgreSQLConnection(
'10.0.2.2', 5432, DatabaseAccess.databaseName,
queryTimeoutInSeconds: 3600,
timeoutInSeconds: 3600,
username: DatabaseAccess.databaseUser,
password: DatabaseAccess.databasePassword);
Future<AppUser?> getCurrentUser() async {
try {
await connection.open();
final result = await connection.mappedResultsQuery(
'select * from public.user where email = #emailValue',
substitutionValues: {
'emailValue': email,
},
allowReuse: true,
timeoutInSeconds: 30,
);
final userFromDataBase = result[0]['user']!;
return AppUser(
email: userFromDataBase['email'],
nickname: userFromDataBase['nickname'],
role: userFromDataBase['role'],
firstname: userFromDataBase['firstname'],
lastname: userFromDataBase['lastname'],
);
} on PostgreSQLException catch(e) {
print(ErrorHandler(message: e.toString()));
return null;
}
}
My screen:
class HomeScreen extends HookConsumerWidget {
const HomeScreen({Key? key}) : super(key: key);
#override
Widget build(BuildContext context, WidgetRef ref) {
final currentUser = ref.watch(currentUserProvider);
return Scaffold(
body: currentUser.when(
data: (user) => _buildBody(context, user, ref),
loading: () => const Center(child: CircularProgressIndicator()),
error: (error, _) => _errorBody(context, ref),
)
);
}
Widget _buildBody(BuildContext context, AppUser? user, WidgetRef ref) {
if(user == null) {
return _errorBody(context, ref);
} else {
return Center(child: Text(
'Welcome ${user.getNickname}',
style: const TextStyle(fontSize: 20),
));
}
}
Widget _errorBody(BuildContext context, WidgetRef ref) {
return const Center(child: Text(
"Error: No user found",
style: TextStyle(fontSize: 20, color: Colors.red),
));
}
}

Answer 1

I resolved this issue with the following code. It wasn't a postgres issue but a dark story about riverpod's providers.
My providers.dart :
final futureCurrentUserProvider = Provider<Future<AppUser?>>((ref) {
return UserRepository().getCurrentUser(ref.watch(emailChangeProvider));
});
final currentUserProvider = FutureProvider.autoDispose<AppUser?>((ref) => UserRepository().getCurrentUser(ref.watch(emailChangeProvider)));
final authChangeProvider = StreamProvider<User?>((ref) {
return ref.read(authRepositoryProvider).authUserChange;
});
final emailChangeProvider = Provider<String?>((ref) {
return ref.watch(authChangeProvider).value?.email;
});