Question & Feature Request: Selective Notifications & Cancellation

[Pulkit077]

First of all, I want to sincerely appreciate the effort put into developing background_downloader.

I've a few queries I would like to discuss here.
Here's the code snippet which I am using

class DownloadService {
  static DownloadService? _instance;
  static FileDownloader? _fileDownloader;

  DownloadService._internal() {
    _init();
  }

  factory DownloadService() {
    _instance ??= DownloadService._internal();
    return _instance!;
  }

  static FileDownloader get fileDownloader {
    _fileDownloader ??= FileDownloader();
    return _fileDownloader!;
  }

  Future<void> _init() async {
    await _requestPermissions();
    
    fileDownloader
        .registerCallbacks(taskNotificationTapCallback: _notificationTapCallback)
        .configureNotification(
          progressBar: true,
          running: const TaskNotification('Download running', 'Downloading {metadata}: {displayName}'),
          complete: const TaskNotification('Download completed', 'Downloaded {metadata}: {displayName}'),
          error: const TaskNotification('Download failed', 'Downloading {metadata} {displayName} failed'),
        );

    fileDownloader.start();
  }

  Future<void> _requestPermissions() async {
    await Permission.notification.request();
  }

  void _notificationTapCallback(Task task, NotificationType notificationType) {
    print('Tapped notification $notificationType for taskId ${task.taskId}');
  }

  Future<void> downloadFiles({
    required List<DownloadTask> tasks,
    required void Function(TaskStatusUpdate) taskStatusCallback,
    required void Function(TaskProgressUpdate) taskProgressCallback,
  }) async {
    try {
      await fileDownloader.downloadBatch(
        tasks,
        taskStatusCallback: taskStatusCallback,
        taskProgressCallback: taskProgressCallback,
      );
    } catch (e) {
      print("Error while downloading: ${e.toString()}");
    }
  }

  Future<bool?> cancelDownloads(List<String> taskIds) async {
    try {
      return await fileDownloader.cancelTasksWithIds(taskIds);
    } catch (e) {
      print("Error cancelling downloads: ${e.toString()}");
      return null;
    }
  }
}

1: Selective Notifications for Downloads: Assume I queue 5 download tasks (e.g., 5 episodes in a list) then Is there an option to selectively enable/disable notifications for specific downloads in the batch?

2: Handling Notification for Canceled Downloads: When I cancel a download, the notification seems to trigger an error response. In configureNotification, is there any existing field to handle cancellation properly and prevent an error notification?

Thanks ((:

[781flyingdutchman]

Hi, thanks for the feedback. Response:

1. You can use configureNotificationForTask or configureNotificationForGroup for more fine-grained notification controls. These 'override' the general notification configuration you have set in your code above (so if not set for a task, it defaults back to your general setting, or none if you didn't set any)
2. Currently, a cancellation indeed results in the error notification - that is working as intended. I am working on an significant update and made a note to allow setting a separate TaskNotification for a cancelled task (which, if omitted, results in no notification). Unless I run into unforeseen issues with that, expect this in version 9

[781flyingdutchman]

The cancel notification has been added to the V9 branch (which will become main shortly). To try it, change your pubspec.yaml to:

background_downloader:
    git:
      url: https://github.com/781flyingdutchman/background_downloader.git
      ref: V9

and let me know if this works as intended.

[781flyingdutchman]

Published in V9.0.0